Peptide guides
What each research peptide is, what the published research actually shows (and what kind of study it was), and its regulatory status, with links to the papers. Each guide also shows which suppliers list it and at what price. New to the subject? Start with what research peptides are.
Synthetic gastric peptides
Mitochondrial peptides
- MOTS-cMOTS-c is a 16-amino-acid peptide encoded in mitochondrial DNA, first described in 2015. In mice it improved insulin sensitivity, protected against diet-induced weight gain and increased running capacity, and in people its levels rise during exercise. No clinical trial of MOTS-c itself has published results, it is not an approved medicine, and it is prohibited in sport.90 suppliers13 studies cited
- SS-31ElamipretideSS-31, developed as the drug elamipretide, is a small synthetic peptide that concentrates in mitochondria and binds cardiolipin, a lipid of the inner mitochondrial membrane. It became the first approved treatment for the rare genetic disorder Barth syndrome when the FDA granted accelerated approval in September 2025, but a phase 3 trial in primary mitochondrial myopathy did not meet its goals. SS-31 sold online as a research peptide is not the approved product.63 suppliers8 studies cited
Copper peptides
Thymic peptides
- TB-500Thymosin beta-4 fragmentTB-500 is a synthetic seven-amino-acid peptide, Ac-LKKTETQ, copied from the actin-binding region of the natural protein thymosin beta-4. Most of the research people cite for TB-500 was done with full-length thymosin beta-4, not with TB-500 itself. TB-500 has not been tested in any published human trial and is not an approved medicine.86 suppliers15 studies cited
- Thymosin Alpha-1Tα1 · ThymalfasinThymosin alpha-1 is a 28-amino-acid peptide first isolated from calf thymus in 1977 and studied as an immune modulator. A synthetic version, thymalfasin (Zadaxin), is sold as a medicine in a number of countries, which its manufacturer has said are mainly in Asia, the Middle East and Latin America, but it is not approved by the FDA. Unlike most research peptides, it has been tested in large human trials, with mixed results.38 suppliers8 studies cited
GH secretagogues and GHRH analogues
- IpamorelinIpamorelin is a synthetic five-amino-acid peptide that stimulates growth hormone release by acting on the ghrelin receptor. Developed by Novo Nordisk in the 1990s, it was described as the first secretagogue that released growth hormone without the rises in cortisol and ACTH seen with older GH-releasing peptides. Its only published efficacy trial in people, for post-operative ileus, did not meet its main goal, and it is not an approved medicine.81 suppliers15 studies cited
- CJC-1295Modified GRF (1-29) · CJC-1295 DACCJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH) designed to last for days rather than minutes by binding to albumin in the blood. The name is also used, loosely, for a different peptide sold as “CJC-1295 no DAC” or Modified GRF (1-29), which lacks that albumin-binding group and has no published human studies of its own.72 suppliers10 studies cited
- TesamorelinTesamorelin is a modified form of human growth hormone-releasing hormone (GHRH) and, unlike most peptides sold for research, it is an approved prescription medicine. In the US and Canada it is licensed as Egrifta to reduce excess abdominal fat in adults with HIV-associated lipodystrophy, on the strength of large placebo-controlled phase 3 trials.72 suppliers11 studies cited
- AOD-9604hGH fragment 176-191 analogueAOD-9604 is a 16-amino-acid fragment of human growth hormone, developed in Australia in the late 1990s as an anti-obesity drug. It increased fat breakdown in rodents, but a 536-person phase 2b trial found no significant weight loss compared with placebo and development for obesity was stopped in 2007. It is not an approved medicine, and it is prohibited in sport.61 suppliers10 studies cited
- SermorelinGRF 1-29Sermorelin is a synthetic copy of the first 29 amino acids of human growth hormone-releasing hormone (GHRH), a fragment that keeps the hormone’s growth hormone-releasing activity. It was licensed in the US as Geref for testing and treating growth hormone deficiency in children, but the manufacturer discontinued it in 2008, and the FDA later confirmed the withdrawal was not for safety or effectiveness reasons.53 suppliers10 studies cited
- GHRP-6GHRP-6 is a synthetic six-amino-acid peptide, described in 1984, that stimulates growth hormone release through what is now known as the ghrelin receptor. It is historically important because research on it and similar compounds helped lead to the discovery of that receptor and of ghrelin itself. Human studies are short hormone-response experiments; it has never been approved as a medicine.35 suppliers12 studies cited
- GHRP-2PralmorelinGHRP-2, also called pralmorelin, is a synthetic growth hormone-releasing peptide that acts on the ghrelin receptor. It is the only peptide in the GHRP family that we could confirm has a regulatory approval: in Japan it is used in hospitals as a single-dose diagnostic test for growth hormone deficiency. It has no approved treatment use anywhere.32 suppliers11 studies cited
- HexarelinHexarelin is a synthetic six-amino-acid growth hormone-releasing peptide (GHRP) that acts on the ghrelin receptor. In human studies from the 1990s and 2000s it was among the most potent GH releasers in its class, but its effect weakened with repeated use and it also raised cortisol and prolactin. It was never approved as a medicine.28 suppliers10 studies cited
Neuropeptide analogues
- SelankSelank is a synthetic seven-amino-acid peptide developed in Russia from tuftsin, a short fragment of an immune protein, with a Pro-Gly-Pro sequence added. It is registered in Russia as a 0.15% nasal drop for anxiety states, but the clinical evidence consists of small Russian-language studies, and it is not approved as a medicine in the UK, US, Canada, Australia or New Zealand.81 suppliers10 studies cited
- SemaxSemax is a synthetic seven-amino-acid peptide developed in Russia from a fragment of adrenocorticotropic hormone (ACTH 4-10), with a Pro-Gly-Pro sequence added, and designed to have no hormonal activity. It is registered in Russia as a prescription nasal drop for cognitive and cerebrovascular conditions, but its clinical evidence comes from small Russian studies, and it is not approved in the UK, US, Canada, Australia or New Zealand.78 suppliers9 studies cited
- DSIPDelta sleep-inducing peptideDSIP (delta sleep-inducing peptide) is a nine-amino-acid peptide first isolated in 1977 by a Basel group from the blood of rabbits in which sleep had been induced. Early small studies suggested it might promote sleep, but later double-blind trials in people with chronic insomnia found little clinical benefit, its natural role is still unclear, and it is not an approved medicine.66 suppliers10 studies cited
- Kisspeptin-10KP-10Kisspeptin-10 is the shortest active form of kisspeptin, a natural hormone that switches on the reproductive axis by triggering release of gonadotrophin-releasing hormone (GnRH) from the brain. It has been given to healthy volunteers in a number of academic studies, mainly in the UK and US, as a research tool, but it is not an approved medicine for any condition.34 suppliers10 studies cited
Melanocortin analogues
- KPVLys-Pro-ValKPV is a three-amino-acid peptide (lysine-proline-valine) that matches the final three residues of alpha-melanocyte-stimulating hormone (α-MSH). It has shown anti-inflammatory effects in cell studies and in mouse models of colitis. No human trial of KPV has been published, and it is not an approved medicine.77 suppliers9 studies cited
- PT-141BremelanotidePT-141 is the development code for bremelanotide, a synthetic melanocortin receptor agonist derived from melanotan II. It is the active ingredient of Vyleesi, which the US FDA approved in June 2019 as an as-needed injection for acquired, generalised hypoactive sexual desire disorder (HSDD) in premenopausal women; it is not approved for men or to enhance sexual performance.76 suppliers14 studies cited
- Melanotan IIMT-2 · MT-IIMelanotan II is a synthetic cyclic analogue of alpha-melanocyte-stimulating hormone, developed at the University of Arizona in the late 1980s and early 1990s. It was tested in small human studies for skin tanning and erectile dysfunction but was never approved as a medicine anywhere, and regulators in the UK, Australia and the US have warned against unlicensed tanning products that contain it.47 suppliers15 studies cited
Other synthetic peptides
Incretin analogues
- RetatrutideLY3437943Retatrutide is an investigational once-weekly peptide from Eli Lilly that activates three hormone receptors: GIP, GLP-1 and glucagon. It produced up to 24.2% average weight loss at 48 weeks in a 2023 phase 2 trial, and Lilly has since reported positive phase 3 TRIUMPH results. As of September 2026 it is not an approved medicine anywhere we could confirm, so any retatrutide sold online is unlicensed material, not a medicine.38 suppliers14 studies cited
- CagrilintideCagrilintide is a long-acting, once-weekly analogue of the hormone amylin, developed by Novo Nordisk for weight management. It has been tested alone and, mainly, in combination with semaglutide as CagriSema, which produced 20.4% average weight loss in the phase 3 REDEFINE 1 trial. Novo Nordisk filed CagriSema with the FDA in December 2025; as of September 2026 we found no approval of either cagrilintide or CagriSema.33 suppliers7 studies cited
- TirzepatideTirzepatide is a once-weekly peptide that activates two gut-hormone receptors, GIP and GLP-1. Developed by Eli Lilly, it is licensed as Mounjaro for type 2 diabetes and, in the US, as Zepbound for weight management and obstructive sleep apnoea, on the strength of the SURPASS and SURMOUNT trial programmes. Tirzepatide sold online as a “research peptide” is not the licensed medicine.30 suppliers9 studies cited
- SemaglutideSemaglutide is a long-acting GLP-1 receptor agonist developed by Novo Nordisk and licensed as the prescription medicines Ozempic, Rybelsus and Wegovy for type 2 diabetes and weight management. Its effects are supported by large randomised trials, including the STEP obesity programme and the SELECT cardiovascular outcomes trial. Semaglutide sold online as a “research peptide” is not the licensed medicine and has none of its quality controls.21 suppliers12 studies cited
Antimicrobial peptides
Growth factor analogues
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