Isolated in 1991 by Predrag Sikirić and colleagues at the University of Zagreb from a protective protein found in human gastric juice. "BPC" stands for Body Protection Compound; the 15-amino-acid fragment labeled "157" has been the focus of nearly all published research since.

BPC-157 upregulates growth factor receptors — particularly VEGFR2 — driving angiogenesis (new blood vessel formation) at injury sites. It also modulates nitric oxide signaling and interacts with the dopaminergic, serotonergic, and GABAergic systems, which helps explain its gut-brain axis effects. Mechanistically it accelerates the transition from inflammation to proliferation in the wound-healing cascade.

Animal models are extensive. Staresinic et al. (2006) demonstrated accelerated Achilles tendon transection repair in rats. Cerovecki et al. (2010) and Chang et al. (2011) showed tendon-to-bone healing improvements. Klicek et al. (2013) documented gastrointestinal fistula closure. Boban-Blagaic et al. (2008) reported reversal of SSRI-induced GI damage. Additional rat studies have covered muscle laceration, ligament injury, bone defects, and traumatic brain injury.

Human data is very limited — mostly case reports and small observational series in GI conditions. No large randomized trials exist, which is the most important caveat.

TB-500 (systemic repair complement), GHK-Cu (collagen and connective tissue quality), KPV (inflammatory damping, especially in gut protocols).

Active cancer or cancer history — BPC-157 drives angiogenesis (new blood vessel formation) via VEGFR2 upregulation. That same mechanism could theoretically support tumor vascularization. No direct evidence of tumor promotion exists in the literature, but the mechanistic concern is real enough to warrant caution. Pregnancy and breastfeeding — no safety data in humans.

Thymosin Beta-4 (Tβ4) was first isolated from calf thymus in 1981 by Low and Goldstein. TB-500 is the synthetic C-terminal fragment of Tβ4 that carries most of its regenerative activity and became the preferred research form due to better stability.

TB-500 binds G-actin — a cytoskeletal protein involved in cell shape and migration. That binding promotes cell migration to injury sites, upregulates laminin-5, and drives angiogenesis. Unlike localized agents, it acts systemically: injected anywhere, it distributes broadly to circulate healing signals throughout the body.

Animal models are well-developed. Crockford et al. (2010) showed cardiac regeneration after myocardial infarction in mice. Sosne and colleagues published a long series on corneal epithelial repair from 2005 onward. Goldstein et al. documented dermal wound healing, and TB-500 has been widely studied in equine performance and injury recovery literature.

Human data is limited. A clinical formulation of full-length Tβ4 (RGN-259) has moved through Phase 2/3 trials for dry eye and corneal wounds, which is the closest direct human evidence.

BPC-157 (local + systemic recovery), GHK-Cu (collagen quality), KPV (for inflammation-heavy injuries).

Active cancer or cancer history — TB-500's core mechanism involves promoting cell migration to injury sites and driving angiogenesis. These same properties overlap with processes that support metastasis. No direct evidence of tumor promotion exists, but the mechanistic concern warrants caution in anyone with a cancer history. Pregnancy — insufficient human safety data.

Isolated from human plasma in 1973 by Loren Pickart, who observed that plasma from younger donors had regenerative effects on aged liver tissue. The active agent turned out to be a tripeptide (glycyl-histidyl-lysine) bound to copper. Plasma levels of GHK drop roughly 60% between age 20 and age 60 — the observation that launched decades of research.

GHK-Cu is a copper carrier and a transcriptional modulator. Pickart and Margolina's 2012 gene array work showed it influences expression of roughly 4,000 human genes — shifting expression patterns away from aged/damaged profiles toward healthier, regenerative ones. Downstream it stimulates collagen and elastin synthesis, upregulates decorin (tissue quality), and suppresses several inflammatory signaling pathways.

Animal and in vitro research is extensive. Maquart et al. (1988) demonstrated wound healing acceleration. Trachy et al. (1990) showed hair follicle stimulation. Pickart and colleagues have published on gene expression reset, stem cell stimulation, and skin regeneration over decades.

Human data exists primarily for topical use — multiple trials show improvements in skin firmness, wound healing, and age-related skin quality. Injectable human research is limited but clinical use is widespread.

BPC-157 and TB-500 (repair protocols), KPV and Thymosin Alpha-1 (immune/inflammation stacks). Also widely used topically alongside injectable protocols.

Active cancer — GHK-Cu influences expression of thousands of genes, including some involved in growth and proliferation. Topical use at cosmetic doses is generally considered lower risk, but injectable protocols in individuals with active malignancy are best avoided until more clarity exists. Pregnancy — insufficient human safety data for systemic use.

Isolated from the thymus gland in 1977 by Allan Goldstein and Abraham White at Albert Einstein College of Medicine. The full 28-amino-acid sequence was synthesized in 1979, and the compound has been studied continuously since — now approved as Zadaxin in over 35 countries for chronic hepatitis B, hepatitis C, immunodeficiency, and as an adjunct in certain cancers.

Ta1 acts primarily on the adaptive immune system. It binds Toll-like receptors (particularly TLR2 and TLR9) on dendritic cells, enhances maturation of T-cells in the thymus, increases NK-cell cytotoxicity, and helps balance Th1/Th2 polarization. The net effect is immune normalization — it restores function in blunted immune systems without overactivating healthy ones, which is why it's described as a modulator rather than a stimulator.

Human clinical evidence is unusually robust for a peptide. Andreone et al. (2001) and Sherman et al. (1998) documented efficacy in chronic hepatitis B and C. A meta-analysis by Wu et al. (2013) found Ta1 reduced mortality in severe sepsis. More recently, Liu et al. (2020) and related ICU studies reported reduced mortality in severe COVID-19 when Ta1 was added to standard care — including reversal of T-cell exhaustion.

Additional trials cover melanoma adjunct therapy, vaccine response in the elderly, and chronic immune deficiency. The body of evidence is larger than almost any other research peptide.

KPV (adaptive + innate immune coverage), GHK-Cu (gene-level anti-inflammatory support), BPC-157 (tissue repair in chronic inflammatory conditions).

Active autoimmune conditions — TA-1 enhances T-cell maturation and NK-cell activity. In autoimmune diseases (rheumatoid arthritis, lupus, multiple sclerosis, Crohn's disease), amplifying an already overactive immune response can worsen the underlying condition. The "modulator" description applies to blunted immune states — it does not reliably calm an overactive one. Solid organ transplant recipients on immunosuppression — increased immune activity could raise rejection risk. Pregnancy — insufficient data.

KPV (Lys-Pro-Val) is the C-terminal tripeptide of α-melanocyte-stimulating hormone (α-MSH). Researchers in the 1990s and early 2000s characterized it as the anti-inflammatory "active site" of the larger hormone — it retains most of the anti-inflammatory activity of α-MSH without the pigmentation and cardiovascular effects of the full peptide.

KPV inhibits NF-κB, the master regulator of inflammatory gene transcription. That suppresses pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and calms overactive macrophages and mast cells. Critically, KPV is transported into cells via PepT1 — a peptide transporter heavily expressed in the gut — which concentrates its effect on intestinal epithelium and makes it particularly useful for GI inflammation.

Animal and in vitro work is the primary evidence base. Kannengiesser et al. (2008) demonstrated colitis reduction in mouse models. Dalmasso et al. (2008) showed targeted nanoparticle delivery of KPV was highly effective in experimental IBD. Multiple papers have documented effects in skin inflammation, ocular inflammation, and joint models.

Human research is limited to early-stage work and off-label clinical use, primarily in IBD and chronic inflammatory conditions. The mechanistic case is strong; the formal clinical trial base is still developing.

BPC-157 (gut repair protocols — the two are highly complementary), Thymosin Alpha-1 (immune dysregulation), GHK-Cu (broad anti-inflammatory stacks).

Severe systemic immunodeficiency (e.g., advanced HIV with very low CD4 count) — further dampening inflammatory responses via NF-κB suppression may reduce the body's ability to fight active infections. Pregnancy — insufficient human safety data. KPV is otherwise one of the better-tolerated compounds in this category, with a notably clean side-effect profile in available research.

Developed by ConjuChem in the early 2000s. The Drug Affinity Complex (DAC) version was published in Teichman et al. (2006) — a GHRH analog modified to covalently bind serum albumin, dramatically extending its half-life from minutes to roughly a week. Most research peptide sources today sell the non-DAC "Mod GRF 1-29" version, which is shorter-acting but otherwise similar.

CJC-1295 is a GHRH (growth hormone-releasing hormone) analog. It binds pituitary GHRH receptors and extends the window during which the pituitary will release GH. It doesn't force a pulse — it primes the system. That's why it's typically paired with a GHRP like Ipamorelin, which fires the actual pulse.

Teichman et al. (2006) demonstrated dose-dependent increases in GH and IGF-1 in healthy adults with the DAC version, with a reasonable safety profile in short-term trials. Most other research is in livestock and animal models. Long-term human safety data is limited, which is the primary caveat for extended use.

Ipamorelin — the pairing is synergistic and is the standard GH secretagogue protocol. Both are typically dosed pre-sleep to amplify the natural nocturnal GH surge.

Active malignancy or cancer history — GH and downstream IGF-1 are established promoters of tumor cell proliferation. Any compound that raises GH or IGF-1 is contraindicated in individuals with active cancer or a significant cancer history. This is one of the clearest contraindications across the GH secretagogue class. Acromegaly or pituitary tumors — further GH stimulation in already-elevated GH states is dangerous. Uncontrolled type 2 diabetes — IGF-1 elevation complicates glycemic management. Pregnancy.

Developed by Novo Nordisk and published by Raun et al. (1998). Designed specifically as a cleaner GHRP — one that delivered the growth hormone release of older compounds like GHRP-6 without their side effects (hunger, prolactin and cortisol spikes).

Ipamorelin is a selective ghrelin receptor (GHS-R) agonist. It triggers a pituitary GH pulse with minimal effect on cortisol, prolactin, or ACTH — which is what differentiates it from the earlier GHRP generation. It works synergistically with GHRH analogs (CJC-1295, Sermorelin) because the two pathways converge on GH release through different mechanisms.

Raun et al. (1998) demonstrated clean GH release in rats and humans. Subsequent trials have examined post-operative ileus and gastrointestinal motility. Longer-term body composition and safety data in healthy adults is limited — most formal research focused on the GH-release pharmacology.

CJC-1295 or Sermorelin — the GHRP + GHRH pairing is the foundation of most GH secretagogue protocols. Also paired with Tesamorelin in more advanced protocols for stronger GH amplitude.

Active malignancy or cancer history — same concern as all GH secretagogues; IGF-1 elevation drives tumor cell proliferation. This applies across the entire GH axis compound class. Acromegaly or active pituitary tumors. Uncontrolled diabetes — IGF-1 effects on glucose metabolism can complicate management. Pregnancy. Ipamorelin is among the cleanest GHRPs from a side-effect standpoint, but the cancer/GH contraindication is class-wide and non-negotiable.

The 29-amino-acid N-terminal fragment of endogenous GHRH. Approved by the FDA in 1997 as Geref for pediatric growth hormone deficiency, making it one of the few GH secretagogues with a long regulatory history.

Sermorelin binds pituitary GHRH receptors and triggers endogenous pulsatile GH release — essentially the same mechanism the body uses naturally. Because it respects the body's feedback loops, it carries a lower risk of receptor desensitization or HPA disruption than exogenous GH. Half-life is short (~10 minutes), so dosing is typically pre-sleep to align with natural GH rhythms.

Extensive pediatric GHD literature supported FDA approval. Adult off-label use for age-related GH decline has smaller clinical evidence — primarily Walker et al. and related groups showing improved IGF-1, sleep quality, and body composition markers in older adults over 6–12 months of use.

Ipamorelin (GHRH + GHRP synergy — similar logic to CJC-1295 + Ipamorelin but with a shorter GHRH duration).

Active malignancy or cancer history — GH/IGF-1 elevation is contraindicated across all GH secretagogues. Pituitary tumors or acromegaly. Active hypothyroidism — GH response is significantly blunted when thyroid function is low; hypothyroidism should be treated before starting any GH secretagogue. Uncontrolled diabetes. Pregnancy. Sermorelin's short half-life and regulatory history (FDA-approved for pediatric GHD) give it one of the cleaner safety profiles in this class, but the above contraindications still apply.

FDA-approved in 2010 as Egrifta for HIV-associated lipodystrophy (abnormal visceral fat accumulation in HIV patients on antiretroviral therapy). A modified GHRH(1-44) with an N-terminal trans-3-hexenoyl group that dramatically improves stability and half-life.

Like other GHRH analogs, Tesamorelin drives endogenous pulsatile GH release from the pituitary. Its distinguishing feature is efficacy — it produces larger, more sustained GH/IGF-1 increases than Sermorelin and has the cleanest human trial record for visceral fat reduction specifically.

Falutz et al. (2007, 2008, 2010) established efficacy for visceral adiposity reduction in HIV populations across multiple Phase 3 trials. Stanley et al. (2014) reported cognitive improvements (verbal memory, executive function) in older adults with age-related cognitive decline. Subsequent work has documented liver fat reduction in NAFLD. Among research peptides, Tesamorelin's human evidence base is among the strongest.

Often used alone given its potency. Can be paired with Ipamorelin for stronger pulse amplitude, though this is less necessary than with shorter-acting GHRHs.

Active malignancy or cancer history — the FDA's Egrifta prescribing information explicitly contraindicates Tesamorelin in patients with active malignancy. Active pituitary tumor or hypopituitarism. Pregnancy — contraindicated in FDA labeling. Uncontrolled diabetes or insulin resistance — Tesamorelin raises IGF-1 substantially and can meaningfully worsen glycemic control; baseline and ongoing glucose monitoring is required. Fluid retention disorders — GH elevation can worsen edema in patients with underlying cardiac or renal compromise.

Developed by Romano Deghenghi's group in the 1990s as a modified hexapeptide analog of GHRP-6 — specifically engineered for stronger GH-releasing activity and better oral/intranasal bioavailability than first-generation GHRPs.

Hexarelin is a ghrelin receptor (GHS-R) agonist — the same receptor Ipamorelin targets — but it produces a markedly larger GH pulse. It also binds CD36, a scavenger receptor on cardiac tissue, giving it direct cardioprotective effects independent of GH release. The tradeoff: Hexarelin is the GHRP most prone to tachyphylaxis — receptor desensitization with continuous use — so it's typically cycled aggressively rather than run long-term.

Locatelli et al. (1994) and Imbimbo et al. (1994) established potent GH release in animal and human studies. Torsello et al. (2003) and follow-up work by Broglio and Ghigo documented independent cardioprotective effects — reduced ischemia-reperfusion damage via CD36, not GH. Desensitization with chronic use has been well-characterized, limiting long-duration protocols.

CJC-1295 or Sermorelin (GHRH + potent GHRP for maximum pulse). Cycled use only — typically 2–4 weeks on, extended off, to avoid receptor desensitization.

Active malignancy or cancer history — same GH/IGF-1 tumor promotion concern as the full secretagogue class. Acromegaly or active pituitary tumors. Significant cardiovascular disease — Hexarelin's stronger GH pulse produces a more pronounced transient blood pressure elevation than milder GHRPs; this is generally well tolerated in healthy individuals but may not be in those with serious cardiac pathology. Pregnancy. Note that tachyphylaxis with continuous use is not a safety concern per se, but it does mean prolonged continuous protocols are self-defeating.

Developed in the late 1980s by Francesco and colleagues as a modified IGF-1 analog initially intended for cell culture research. It acquired its name from its two structural changes: a 13-amino-acid N-terminal "Long" extension and an arginine ("Arg") substitution at position 3 of the native IGF-1 sequence. Those small changes transformed the molecule's pharmacokinetics dramatically.

Native IGF-1 circulates almost entirely bound to IGF-binding proteins (IGFBP-1 through -6), which protect it but also restrict when and where it acts. The Arg3 substitution disrupts binding to IGFBP-3 (the dominant carrier), leaving LR3 largely free in circulation. The N-terminal extension extends half-life from roughly 12 minutes (native IGF-1) to approximately 20–30 hours. The net effect: sustained, unrestricted IGF-1 receptor activation — driving the PI3K/Akt/mTOR pathway for protein synthesis, muscle hypertrophy, and hyperplasia (increased muscle cell count, not just size).

The compound was never developed for human therapeutic use, so formal human clinical trials don't exist. Native IGF-1 (Mecasermin/Increlex) is FDA-approved for severe primary IGF-1 deficiency and provides the closest translational evidence base. Animal studies show potent lean mass increases with LR3 (Tomas et al. 1992; Bailey et al. 1993). Its use in performance contexts is informed primarily by this preclinical work, native IGF-1 clinical data, and decades of off-label user experience — which is not the same as validated safety data.

Hypoglycemia — IGF-1 receptors have structural overlap with insulin receptors; large doses can cause significant blood glucose drops. Have fast carbs available.

Organ hypertrophy — IGF-1 drives growth in all tissues with IGF-1 receptors, not just muscle. Chronic high doses have been associated with gut wall thickening, cardiac hypertrophy, and visceral growth. Cycles should be short (4–6 weeks), not continuous.

Tumor promotion concerns — elevated IGF-1 signaling is a growth signal to any existing cancerous or precancerous tissue. This is an absolute contraindication for anyone with cancer history or elevated cancer risk.

CJC-1295 + Ipamorelin (endogenous GH pulse alongside direct IGF-1 signaling — the canonical advanced hypertrophy combination). BPC-157 supports tendon and connective tissue repair during aggressive hypertrophy phases, which often lag behind muscle growth. Not paired with other growth-heavy compounds given cumulative risk.

Anyone with cancer or elevated cancer risk — direct, unrestricted IGF-1 receptor activation is a growth signal for any tissue with IGF-1 receptors, including tumor tissue. This is an absolute contraindication. Elevated IGF-1 is specifically associated with increased risk of colorectal, prostate, and breast cancer. Diabetics without a hypoglycemia management plan — blood glucose drops can be rapid and significant; fast-acting carbohydrates must be on hand. Anyone not meeting the "experienced researcher" bar described in the warning above. Pregnancy.

Developed by Vladimir Khavinson and colleagues at the St. Petersburg Institute of Bioregulation and Gerontology in the 1980s as a synthetic analog of Epithalamin — a natural peptide extract from the bovine pineal gland. Khavinson's group spent decades studying its effects on aging and longevity in both animal models and human trials, publishing extensively in Russian literature before it gained wider Western attention.

Epithalon activates telomerase — the enzyme responsible for adding protective telomere sequences to chromosome ends. Telomere shortening is one of the most well-characterized hallmarks of cellular aging; by stimulating telomerase, Epithalon may slow or partially reverse this process. It also regulates melatonin and cortisol production via the pineal gland, normalizing circadian hormone rhythms that drift with age. Additionally, it appears to reduce lipid peroxidation and improve antioxidant enzyme activity.

Khavinson et al. demonstrated telomerase activation and telomere elongation in human somatic cells in culture (2003). Animal studies showed increased median and maximum lifespan in mice and rats. A long-term human study followed elderly patients treated with Epithalon over several years and reported reduced cardiovascular events and improved biomarkers. The research base is substantial but heavily concentrated in Russian institutions — independent Western replication remains limited, though interest has grown significantly.

NAD+ (complementary longevity mechanisms — telomere support + sirtuin activation), GHK-Cu (tissue regeneration + gene expression regulation), Thymosin Alpha-1 (immune resilience for a comprehensive anti-aging protocol). Typically used in concentrated 10–20 day cycles rather than continuous dosing.

Active cancer or cancer history — telomerase activation is a double-edged mechanism. In normal somatic cells, elongating telomeres slows aging; in cancer cells, most of which are already telomerase-active, the effect is less clear but the theoretical risk of supporting tumor longevity exists. Khavinson's research focused on healthy aging populations — individuals with existing malignancy should exercise caution. Pregnancy — no human safety data.

Identified by the Cohen lab at USC in 2015 (Lee et al.) as the first known mitochondrial-derived peptide — encoded in the mitochondrial 12S rRNA gene rather than the nuclear genome. Its existence rewrote assumptions about what mitochondria produce beyond energy.

MOTS-C activates AMPK — the cell's master energy-sensing kinase. Downstream effects include enhanced glucose uptake (independent of insulin), increased fatty acid oxidation, and improved metabolic flexibility. Endogenous MOTS-C levels decline sharply with age and with metabolic disease, which has positioned it as a candidate exercise-mimetic and longevity peptide.

Lee et al. (2015) demonstrated improved insulin sensitivity, exercise capacity, and metabolic profiles in aged mice. Reynolds et al. (2021) characterized the exercise-mimetic profile and showed training-like adaptations in sedentary animals. Human trials are early-stage but actively underway — CohBar and other groups have moved analogs into Phase 1/2 development.

SS-31 (membrane-level complement to biogenesis signal), NAD+ (provides the redox substrate for AMPK-driven metabolism). The SS-31 → MOTS-C → NAD+ stack is the canonical "mitochondrial" protocol.

Type 1 diabetics on insulin — MOTS-C drives glucose uptake via AMPK independently of insulin. Stacking these effects can cause meaningful hypoglycemia; close glucose monitoring is required if used in this population. Pregnancy — insufficient data. MOTS-C otherwise has a notably clean profile in available research, with no significant adverse events reported in animal studies to date.

Developed by Hazel Szeto and Peter Schiller around 2004 as part of a series of cell-penetrating antioxidant peptides. Stealth Biotherapeutics licensed it as Elamipretide and has moved it through multiple late-stage clinical trials for mitochondrial disease.

SS-31 is a cationic tetrapeptide that concentrates selectively on the inner mitochondrial membrane by binding cardiolipin — a phospholipid that holds the electron transport chain in its proper cristae geometry. Stabilizing cardiolipin restores efficient ETC organization, reduces electron leak, and lowers reactive oxygen species production at the source rather than mopping them up downstream.

Human clinical trials are unusually advanced for this class. Sabbah et al. (2016) showed improvements in heart failure patients. Karaa et al. (2020) reported vision improvements in Leber hereditary optic neuropathy. Phase 3 trials have covered primary mitochondrial myopathy and Barth syndrome with mixed but informative results. Preclinical work covers ischemia-reperfusion injury, kidney disease, and neurodegeneration.

MOTS-C (SS-31 stabilizes the existing machinery; MOTS-C builds new machinery), NAD+ (redox substrate for the stabilized ETC). Typically introduced first in a mitochondrial stack to establish the membrane foundation.

SS-31 has one of the cleanest tolerability profiles across all compounds in this library — Phase 2/3 trials in serious mitochondrial diseases reported minimal adverse events. Severe renal impairment warrants caution given limited pharmacokinetic data in that population. Pregnancy — insufficient data. No strong absolute contraindications have emerged from the available human trial data.

Identified by Arthur Harden and William Young in 1906 as a "coferment" required for yeast fermentation — the first coenzyme ever characterized. A century of work has since established it as fundamental to virtually all cellular energy metabolism and a central molecule in aging research.

NAD+ is an electron carrier in the mitochondrial electron transport chain and the required substrate for sirtuins (SIRT1–SIRT7), PARPs (DNA repair), and CD38. Cellular NAD+ levels decline substantially with age, and that decline impairs mitochondrial function, DNA repair, and circadian signaling. Injectable NAD+ delivers the intact molecule directly rather than relying on precursor conversion.

The underlying biology is extensively characterized across thousands of papers. Precursor trials (NMN, NR) have shown raised blood NAD+ levels and some metabolic benefits in human trials. Direct subcutaneous/IV NAD+ has less formal trial data but a long history of clinical use in addiction medicine and increasingly in longevity clinics. The gap between mechanistic strength and formal trial coverage is the main caveat.

SS-31 and MOTS-C (complete mitochondrial stack — NAD+ provides the fuel for improved ETC function), Glutathione (redox + antioxidant synergy).

Active malignancy — an unsettled but legitimate concern: cancer cells rely heavily on NAD+ for energy metabolism (PARP activity, glycolysis), and supplementation may support tumor bioenergetics. This is not an established contraindication with the same certainty as GH compounds, but individuals with active cancer should discuss with their oncologist before using. G6PD deficiency — the high redox load of NAD+ supplementation is a theoretical concern in this enzyme deficiency. Pregnancy at high IV doses. At standard subcutaneous doses, NAD+ is generally well tolerated.

Characterized by Frederick Gowland Hopkins in 1921 as a thiol-containing tripeptide of glutamate, cysteine, and glycine. Decades of subsequent work established it as the primary intracellular antioxidant in essentially every human cell and a central cofactor in phase II liver detoxification.

Glutathione works through its active thiol (-SH) group, directly neutralizing reactive oxygen species and serving as the substrate for glutathione peroxidases (GPx) and glutathione-S-transferases (GST) — enzymes responsible for clearing peroxides and conjugating toxins for excretion. Intracellular levels drop under oxidative stress, chronic inflammation, alcohol exposure, acetaminophen toxicity, and normal aging. Injectable/IV glutathione bypasses the GI breakdown that limits oral absorption.

Sechi et al. (1996) reported symptom improvement in Parkinson's disease with IV glutathione. Honda et al. (2017) documented ALT improvements in NAFLD patients with oral glutathione, and IV protocols have small-scale trial support for oxidative conditions. In dermatology, multiple trials have examined IV glutathione for skin lightening with variable results. Subcutaneous dosing is widely used clinically but has less formal trial coverage than IV.

NAD+ (redox/antioxidant synergy), mitochondrial stacks generally, and recovery/detox protocols following high-stress or high-training phases.

Asthma or aspirin-exacerbated respiratory disease (AERD) — IV glutathione can trigger bronchospasm in sensitive individuals due to sulfite content; subcutaneous dosing at standard doses is considerably lower risk. IV use outside a clinical setting — IV glutathione at high doses requires monitoring and should not be self-administered. Glutathione is otherwise among the safest compounds in this library; no significant contraindications have emerged at standard subcutaneous doses. Pregnancy at high IV doses — subcutaneous use at conservative doses is generally considered low risk.

Developed by Eli Lilly; entered Phase 2 clinical trials around 2022. Built on the GLP-1/GIP dual agonist framework pioneered by Tirzepatide, with a third activity added at the glucagon receptor.

Retatrutide is a single molecule that activates all three receptors: GLP-1 (appetite suppression, insulin sensitivity), GIP (insulin response, fat metabolism), and glucagon (increased energy expenditure, hepatic fat mobilization). The glucagon arm is what differentiates it — it adds thermogenic and lipolytic activity on top of the appetite-suppression effects of the GLP-1/GIP duo.

Jastreboff et al. (NEJM 2023) reported the Phase 2 trial: approximately 24% body weight loss at 48 weeks at the highest dose in adults with obesity — the largest reduction of any GLP-class agent to that point. Additional trials have documented hepatic fat reduction in NAFLD. Phase 3 trials are ongoing. Titrate slowly; GI side effects are dose-limiting.

CJC-1295 + Ipamorelin (muscle preservation during aggressive fat loss), MOTS-C (improved cellular fuel utilization), AOD-9604 (targeted lipolysis).

Prior pancreatitis — the most clinically meaningful concern; GLP-class agents slow gastric motility and have been associated with pancreatitis. Anyone with a history of acute or chronic pancreatitis should avoid or proceed only under close clinical supervision. Gallbladder disease — GLP-1 receptor agonists reduce gallbladder motility, increasing the risk of gallstones and cholecystitis. Existing gallbladder issues can worsen significantly. Severe gastroparesis — gastric emptying is further slowed. Active eating disorders — appetite suppression in this context can reinforce dangerous restriction patterns. Pregnancy. Personal or family history of medullary thyroid carcinoma (MTC) or MEN2 — the FDA boxed warning exists based on rodent data showing thyroid C-cell tumors; however, large human epidemiological studies have not shown an increased risk of thyroid cancer in GLP-1 users. The label warning remains in place, but the actual human risk appears to be low based on current evidence.

Developed by Eli Lilly; FDA-approved in 2022 as Mounjaro for type 2 diabetes, and subsequently as Zepbound for chronic weight management. The first dual GLP-1/GIP agonist to reach market.

A single peptide that activates both GLP-1 and GIP receptors. GLP-1 suppresses appetite, slows gastric emptying, and improves insulin secretion. GIP enhances insulin response and influences fat storage — and the combination appears more effective than either alone for body composition.

The SURPASS trials (type 2 diabetes) and SURMOUNT trials (obesity) established efficacy and safety across large populations. SURMOUNT-1 reported roughly 21% body weight loss at the highest dose at 72 weeks. Real-world and subgroup data continue to accumulate given approval status.

CJC-1295 + Ipamorelin (muscle preservation during fat loss), AOD-9604 (targeted fat mobilization on top of systemic effect).

Prior pancreatitis — the primary clinical concern for this class; GLP-1 agents have been associated with pancreatitis and anyone with a history of it should avoid or proceed under supervision. Gallbladder disease — reduced gallbladder motility increases gallstone and cholecystitis risk; pre-existing gallbladder conditions can worsen. Severe gastroparesis. Active eating disorders. Pregnancy. Personal or family history of MTC or MEN2 — the FDA boxed warning is based on rodent data; large human studies have not demonstrated an increased thyroid cancer risk in GLP-1 users, but the label warning remains.

Developed by Novo Nordisk as the successor to liraglutide. FDA-approved in 2017 as Ozempic for type 2 diabetes and in 2021 as Wegovy for chronic weight management. The molecule is engineered for once-weekly dosing via fatty-acid acylation that binds serum albumin and resists DPP-4 degradation.

Semaglutide is a GLP-1 receptor agonist. It suppresses appetite at hypothalamic centers, slows gastric emptying (which prolongs satiety), improves glucose-dependent insulin secretion, and reduces glucagon release. Unlike the dual/triple agonists that followed it, Semaglutide is single-receptor — simpler pharmacology, extensive safety data, but lower peak efficacy for weight loss than Tirzepatide or Retatrutide.

The SUSTAIN trials established efficacy and safety in type 2 diabetes. The STEP program (STEP-1 through STEP-5) documented roughly 15% body weight loss at 68 weeks in adults with obesity. The SELECT trial (2023) showed reduced major adverse cardiovascular events in overweight/obese patients with established cardiovascular disease — a landmark finding that extended the indication beyond metabolic effects.

CJC-1295 + Ipamorelin (lean mass preservation during caloric deficit), MOTS-C (cellular metabolic support), AOD-9604 (targeted lipolysis).

Prior pancreatitis — GLP-1 agents have been associated with pancreatitis; history of this condition warrants avoidance or clinical supervision. Gallbladder disease — reduced gallbladder motility increases gallstone and cholecystitis risk. Diabetics with pre-existing retinopathy — rapid glucose lowering on GLP-1 agents has been associated with worsening of diabetic retinopathy in some patients; Ozempic's label specifically notes this risk. Diabetics with eye complications should have an ophthalmology baseline before starting. Severe gastroparesis. Active eating disorders. Pregnancy. Personal or family history of MTC or MEN2 — FDA boxed warning based on rodent data; large human studies have not shown an increased thyroid cancer risk in GLP-1 users.

Developed at Monash University in the 1990s as a modified C-terminal fragment of human growth hormone (residues 177–191). The goal was to isolate GH's fat-burning activity from its growth and insulin-sensitivity effects.

AOD-9604 selectively activates hormone-sensitive lipase and enhances fat oxidation without binding the GH receptor at meaningful levels. That means it doesn't raise IGF-1, affect blood glucose, or produce the growth effects of full-length GH — it isolates the lipolytic activity. Most effective in fasted state.

Heffernan et al. (2001) documented fat mass reduction in mouse models. Human Phase 2 trials showed modest and variable weight loss effects — not on the scale of GLP-class agents — which has positioned AOD-9604 as a supporting compound rather than a primary fat-loss agent in most modern protocols.

Retatrutide or Tirzepatide (targeted lipolysis on top of systemic appetite suppression), MOTS-C (cellular fat oxidation support), CJC-1295 + Ipamorelin.

AOD-9604 is considered one of the safer GH-derived compounds — it does not raise IGF-1 or bind the GH receptor at meaningful levels, which removes the primary cancer-promotion concern of full-length GH secretagogues. That said, it is still a GH fragment, and individuals with active cancer or a significant cancer history should exercise caution until more targeted safety data exists. Pregnancy — insufficient data.

A small-molecule inhibitor developed in the mid-2010s at the University of Texas Southwestern (Neelakantan et al.) as a tool to probe NNMT — nicotinamide N-methyltransferase — an enzyme overexpressed in adipose and liver tissue in obesity and metabolic disease. Technically a small molecule rather than a peptide, but commonly used alongside peptide protocols for its metabolic effects.

5-Amino-1MQ inhibits NNMT. Normally NNMT consumes methyl groups (SAM) and nicotinamide (an NAD+ precursor) to produce 1-methylnicotinamide. Blocking it raises cellular SAM and NAD+, shifts adipocytes toward fat oxidation, and improves metabolic flexibility. Effectively, it un-throttles the NAD+ salvage pathway in fat tissue specifically.

Neelakantan et al. (2018, 2019) showed reduced adipose mass and improved glucose handling in diet-induced obese mice without calorie restriction. Additional preclinical work covers NAFLD and sarcopenia. No human clinical trial data exists — this is an early-stage research compound with a strong mechanistic case but no translational evidence yet.

Theoretical stacks with MOTS-C and NAD+ (converging on NAD+ availability and AMPK activation) or GLP-class agents (independent mechanism, potential additive fat loss). Pairings are mechanistic rather than trial-validated.

Anyone with pre-existing liver conditions — NNMT is highly expressed in liver tissue and plays a role in hepatic metabolism; inhibiting it in an already-compromised liver introduces unknowns with no human safety data to guide risk assessment. Individuals on medications dependent on methylation pathways — 5-Amino-1MQ affects SAM availability, which is central to many methylation-dependent drug metabolisms. Pregnancy. More broadly: with zero human clinical trial data, this compound carries inherent uncertainty that makes it unsuitable for anyone not genuinely comfortable with first-in-human-level risk.

Developed at Saint Louis University by Thomas Burris's lab as a pan-agonist of the estrogen-related receptors (ERRα, ERRβ, ERRγ). Published in 2023 and widely covered as a potential "exercise-in-a-pill" mimetic. Technically a small molecule, not a peptide — included here because it's frequently discussed alongside metabolic peptides.

ERRs are transcription factors that govern mitochondrial biogenesis, oxidative phosphorylation, and fatty-acid oxidation in skeletal muscle. Exercise upregulates their activity. SLU-PP-332 activates them pharmacologically, driving the same gene-expression program — increased mitochondrial content, oxidative fiber-type shift, and enhanced endurance capacity — without the physical work of training.

Billon et al. (2023) reported that SLU-PP-332 increased running endurance in mice by roughly 70% and produced significant fat loss in diet-induced obesity models without changes in food intake or physical activity. No human data exists. Safety, dosing, and long-term effects in humans are entirely unknown. Strictly experimental.

Theoretical synergy with MOTS-C (converging on mitochondrial biogenesis) and SS-31 (membrane stabilization of newly built mitochondria). Pairings are entirely hypothesis-level given the absence of human trials.

With no human clinical data of any kind, this compound is effectively contraindicated for anyone outside a formal research context. Specific concerns: cardiac conditions — ERR activation significantly alters cardiac energy metabolism in animal models, and human implications are entirely unknown. Any significant pre-existing health condition — there is no safety framework to evaluate interactions. Pregnancy. If the absence of human trial data gives you pause, that instinct is correct. Do not extrapolate from mouse data to human safety.

Developed by Peter de Keizer and colleagues at Erasmus University Medical Center (Netherlands) and published in Cell in 2017. De Keizer's lab was studying how senescent cells resist apoptosis — the programmed cell death that should eliminate damaged or dysfunctional cells — and identified FOXO4 as a key survival factor. FOXO4-DRI is a retro-inverso peptide: it uses D-amino acids in reverse sequence, making it highly protease-resistant and giving it a longer effective half-life than natural peptides. The 2017 paper produced some of the most striking mouse data in senolytic research — rejuvenating fur density, kidney function, and running capacity in aged mice — and catalyzed significant interest in peptide-based senolytics.

Senescent cells — cells that have permanently stopped dividing but refuse to die — accumulate with age and drive chronic inflammation via the senescence-associated secretory phenotype (SASP). They survive by hijacking the apoptotic machinery: FOXO4, a transcription factor, physically interacts with p53 in the nucleus and sequesters it, preventing p53 from triggering PUMA-driven apoptosis. FOXO4-DRI competitively disrupts this FOXO4-p53 interaction. Once the complex is broken, p53 is free to activate the intrinsic apoptosis pathway — but only in senescent cells that depend on FOXO4 for survival. Normal (non-senescent) cells do not rely on FOXO4-p53 sequestration, so they are largely spared. The selectivity is the key property: unlike broad cytotoxics, FOXO4-DRI targets the escape mechanism specific to cellular senescence.

De Keizer et al. (Cell, 2017) remains the foundational paper. In naturally aged mice, three doses over three days produced striking improvements: restored physical fitness (grip strength and running capacity), improved kidney function, and recovery of chemotherapy-induced alopecia — all attributed to selective clearance of senescent cells. In vitro work confirmed selectivity against senescent versus normal human fibroblasts and cancer cell lines. Human data is essentially absent — FOXO4-DRI has not entered formal clinical trials as of 2025. All human use is extrapolation from the animal literature, placing it firmly in the frontier/exploratory category alongside early senolytics like Dasatinib+Quercetin (which have entered Phase 1/2 trials, providing some human-senolytic context).

Thymosin Alpha-1 — after senescent cells undergo apoptosis, the immune system must clear the debris (efferocytosis via macrophages and NK cells). Immunosenescence impairs this clearance; Ta1 recalibrates the adaptive immune system, supporting the cleanup that follows a senolytic cycle. Without adequate immune function, senescent cell die-off can generate a transient local inflammatory surge. NAD+ — NAD+ decline is itself a driver of cellular senescence; restoring NAD+ availability supports the metabolic demands of cell clearance and the healthy cells that proliferate to fill gaps left by cleared senescent cells. Epithalon — after clearing senescent cells, Epithalon's telomere maintenance supports the health of the cells that remain and divide.

Active cancer or cancer history — p53 dynamics in cancer are complex and unpredictable. While liberating p53 from FOXO4 sequestration is theoretically pro-apoptotic in cancer cells, the overall interaction with oncogenic pathways is not characterized in humans. Do not use without explicit oncology consultation. Active chemotherapy — unknown interactions; the 2017 paper studied chemo-induced senescence models, but co-administration is unexplored. Autoimmune conditions — broad senescent cell clearance triggers immune activity; this is the mechanism, but in autoimmune contexts it introduces unpredictable inflammatory risk. Pregnancy — no safety data. More broadly: with no human clinical trial data and all dosing extrapolated from mouse studies, FOXO4-DRI demands a high threshold of research literacy before anyone considers using it.

Developed in Russia in the 1990s at the Institute of Molecular Genetics and the Zakusov Institute of Pharmacology. Designed as a stable synthetic analog of tuftsin — an endogenous immunomodulatory peptide — with modifications aimed at anxiolytic activity.

Selank modulates GABA-A signaling (similar direction to benzodiazepines but without the receptor binding or dependence profile), influences serotonergic tone, and increases BDNF expression. The net effect is anxiolytic without sedation — it takes the edge off without dulling cognition or causing tolerance.

Russian clinical trials (Medvedev, Zozulya and colleagues through the 2000s) documented efficacy in generalized anxiety disorder with a favorable side-effect profile. Preclinical work has covered memory enhancement, stress resilience, and immunomodulation — including intranasal influenza models. Western trial data is sparse, which is the main caveat.

Semax — the classic pairing; Semax sharpens cognition while Selank calms reactivity, producing focused clarity rather than stimulation.

Active benzodiazepine or barbiturate use — Selank modulates GABAergic tone; combining with drugs that also act on GABA receptors may produce additive CNS depression. Pregnancy — insufficient data. Selank has one of the milder risk profiles in this library; no dependence, tolerance, or significant adverse events have appeared in available clinical research. The main caution is the GABAergic drug interaction above.

Developed in the Soviet Union in the 1980s by Ashmarin and colleagues at Moscow State University. Based on the ACTH(4-10) fragment, modified to strip out hormonal (cortisol-stimulating) activity while preserving the neurotropic effects. Approved in Russia for stroke recovery and other neurological conditions.

Semax upregulates BDNF and NGF — neurotrophic factors tied to neuroplasticity and cognition. It also modulates dopaminergic and serotonergic tone. Effects are typically described as sharper focus, better memory consolidation, and improved mental stamina, without the crash profile of classical stimulants.

Russian clinical trials documented improved recovery after ischemic stroke when Semax was added to standard care, and it has regulatory approval there for that indication. Additional trials cover ADHD, optic nerve conditions, and cognitive performance. As with Selank, the Western randomized trial base is thin and is the primary caveat.

Selank — the Semax (signal) + Selank (noise reduction) combination is the standard cognitive stack.

Seizure disorder or epilepsy — Semax upregulates BDNF and NGF, which can lower seizure threshold in susceptible individuals. Those with a history of seizures should avoid or proceed only under neurological supervision. Bipolar I disorder — neurotrophic stimulation during manic phases may be destabilizing. Pregnancy — insufficient data. Outside these specific populations, Semax has a favorable tolerability record in available research.

Isolated in 1977 by Marcel Monnier and Guido Schoenenberger at the University of Basel. The peptide was identified in cerebral venous blood of rabbits during electrically-induced delta-wave sleep — hence the name. It's a nine-amino-acid sequence that has remained somewhat enigmatic: clearly bioactive, but with a mechanism that still isn't fully characterized.

DSIP's exact molecular targets are not fully mapped. Evidence points to modulation of GABAergic tone, influence on hypothalamic-pituitary signaling (ACTH and GH), and interaction with opioid systems. Effects reported include promotion of slow-wave sleep architecture, attenuation of stress responses, and blunting of opioid withdrawal symptoms. It is not a sedative in the classical sense — it shifts sleep toward deeper phases rather than inducing drowsiness.

Small human studies from the 1980s (Schneider-Helmert, Kaeser) reported improvements in chronic insomnia, stress-related sleep disturbance, and opioid/alcohol withdrawal. Animal studies have covered stress resilience, analgesia, and neuroprotection. The literature is moderate in volume but thin in large randomized trial data — it's a peptide with a long history and relatively modest evidence base for its age.

Selank (anxiety-driven sleep disruption), CJC-1295 + Ipamorelin (pre-sleep GH pulse alongside deeper sleep architecture), Epitalon in longevity-oriented protocols.

Untreated obstructive sleep apnea — DSIP promotes deeper slow-wave sleep, which can worsen apnea episodes if the underlying airway obstruction is not being managed. Treat the apnea first. Concurrent opioid or benzodiazepine use — DSIP interacts with GABAergic and opioid systems; additive CNS depression is a real risk in this combination. Pregnancy — insufficient data.

Developed from Melanotan II (a tanning peptide) when researchers noticed a striking off-target effect — sexual arousal. FDA approved in 2019 as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women.

PT-141 is a non-selective melanocortin receptor agonist, primarily at MC3R and MC4R in the central nervous system. Unlike PDE5 inhibitors (Viagra, Cialis), it doesn't work through vascular dilation — it acts on the brain's arousal circuitry directly. That's why it works in both men and women, and in cases where vascular-based drugs don't.

Multiple Phase 2 and Phase 3 trials established efficacy for female HSDD, leading to FDA approval. Earlier trials examined male erectile dysfunction with positive but modest effects. The main side effect is nausea, which is dose-dependent — and flushing, which is common.

Typically used standalone. Timing (45–90 minutes pre-activity) matters more than stacking for this compound.

Cardiovascular disease, prior MI or stroke, or uncontrolled hypertension — PT-141 causes a transient increase in blood pressure; this is formalized in the FDA prescribing information for Vyleesi and is the primary safety concern with this compound. Anyone with serious cardiovascular history should not use it without explicit medical clearance. Individuals on antihypertensive medications — the BP elevation may require dosage adjustment monitoring. Pregnancy.

The parent KISS1 gene was identified in 1996 in Hershey, Pennsylvania as a metastasis suppressor — the name comes from Hershey's famous "Kisses" chocolates. Its role as the master regulator of reproductive endocrinology was not recognized until the early 2000s, when loss-of-function mutations in its receptor (GPR54/KISS1R) were shown to cause hypogonadotropic hypogonadism (de Roux 2003; Seminara 2003). Kisspeptin-10 is the shortest biologically active fragment of the full kisspeptin peptide.

Kisspeptin is the upstream trigger of the entire hypothalamic-pituitary-gonadal (HPG) axis. It binds KISS1R on hypothalamic neurons that then release GnRH (gonadotropin-releasing hormone), which drives the pituitary to secrete LH and FSH, which in turn stimulate testicular testosterone production in men and ovarian steroidogenesis and ovulation in women. Kisspeptin-10 administration produces a physiological LH/testosterone rise through the body's own pathway rather than exogenous hormone replacement.

Waljit Dhillo's group at Imperial College London has led the human research. Dhillo et al. (2005) first demonstrated dose-dependent LH/testosterone release in healthy men. Chan et al. (2014) extended the work to hypogonadotropic hypogonadism. Abbara et al. have published extensively on kisspeptin as an ovulation trigger in IVF (with lower OHSS risk than hCG) and more recently on sexual response and mood. Trials for male hypoactive sexual desire and post-finasteride syndrome are ongoing. The human evidence base for a "research peptide" is unusually substantial.

Typically used standalone given its upstream role. Research protocols sometimes combine it with PT-141 for sexual response (different mechanisms — central arousal vs. HPG axis activation).

Hormone-sensitive cancers — prostate cancer, estrogen-receptor positive breast cancer, and other sex hormone-driven malignancies are directly stimulated by the LH/FSH/testosterone or estradiol rise Kisspeptin-10 produces. This is an absolute contraindication. Polycystic ovary syndrome (PCOS) — abnormally elevated LH response is a central feature of PCOS; kisspeptin would worsen the hormonal imbalance. Individuals on GnRH agonists or antagonists for cancer suppression — Kisspeptin-10 would directly counteract the therapeutic goal of those medications. IVF patients — should only use under close clinical supervision, as timing relative to follicular development is critical.