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Peptides Explained

Compounds

In short

Reading the whole page takes about 3 minutes.

  • We sort each compound by how well it was tested, and by what the law allows.
  • Approved medicines went through large trials. A regulator checked them before they were sold.
  • Some are still being tested in large trials. They are not approved yet.
  • The rest had little or no testing in people. What they do in people is not well known.
Last reviewed
Long, flat crystals in yellow, orange and blue on a pink background, seen through a microscope.
Crystals of amino acids on a glass slide. The photo was taken through a microscope with polarised light. Photo: Aw1792300 (Wikimedia Commons) CC BY 4.0 Image details

Why are the compounds in groups?

Because how much is known differs a lot. The group tells you how much.
The groups differ in what was tested, and in whether a regulator checked it. How this site sorts each compound. Checked on 22 October 2026.
Approved medicineIn clinical developmentExperimental
Tested in trials in people?Yes In large trials, for example semaglutide and tirzepatide.1,2Yes In registered trials. Some are large, for example for retatrutide.3No Little or no formal testing in people. For BPC-157, TB-500 and KPV, most research is in cells and animals.4,5,6
Benefits and risks weighed by a regulator?Yes Before it was approved.1,2No Not yet. Retatrutide, for example, was not on the EU review list in October 2026.7No No.4,8
Can a Dutch doctor prescribe it?Yes Yes, and a pharmacy supplies it.9No Not in the normal way. Usually it is only available inside a trial.10,11No Not in the normal way.10

So each page works differently. For an approved medicine, it reports what the label and the trials show. For the others, it reports what was studied, in which animals or people, and what is still unknown. Medicines approved only outside the EU, for example in the US, or only by some countries’ own regulators, are in the approved group too. Their page says where, because a Dutch doctor cannot simply prescribe them.10 Products that are not peptides are listed under “Other”.

An approved name does not make every product with that name approved. A vial sold online as “research semaglutide” is not the approved medicine.12 See product risk.

How to read the evidence profile

What does the evidence profile on each card show?

Four separate answers about the research. We never add them up into one score.
Part of the profileThe question it answers
Human clinical evidenceHow far has it been tested in people?
Preclinical volumeHow much lab and animal research exists?
Source independenceHow many separate research groups produced it?
Safety characterisationHow well do we know the harms in people?

The parts are kept apart on purpose. Many animal studies from one lab are not the same as one good trial in people. See how we grade evidence, and the Croatian lab for an example.

Authorised medicines

  • PT-141

    Melanocortin

    PT-141 is bremelanotide. In the US it is a prescription medicine called Vyleesi.

    Human clinical evidence
    Authorised by a regulator
    Preclinical volume
    Minimal
    Source independence
    A few groups
    Safety characterisation
    Partial
  • Semaglutide

    Incretin (GLP-1 family)

    Semaglutide is an authorised EU medicine. Ozempic and Rybelsus treat type 2 diabetes. Wegovy helps manage weight.

    Human clinical evidence
    Authorised by a regulator
    Preclinical volume
    Extensive
    Source independence
    Broadly replicated
    Safety characterisation
    Well characterised
  • Tesamorelin

    Growth-hormone axis

    Tesamorelin is a lab-made version of a brain hormone. It makes the body release more growth hormone.

    Human clinical evidence
    Authorised by a regulator
    Preclinical volume
    Minimal
    Source independence
    A few groups
    Safety characterisation
    Partial
  • Tirzepatide

    Incretin (GLP-1 family)

    Tirzepatide is an approved EU medicine called Mounjaro. It treats type 2 diabetes and helps manage weight.

    Human clinical evidence
    Authorised by a regulator
    Preclinical volume
    Extensive
    Source independence
    Broadly replicated
    Safety characterisation
    Well characterised
  • SS-31

    Mitochondrial Short page

    SS-31 is a lab-made chain of four amino acids. Its medicine name is elamipretide.

    Human clinical evidence
    Authorised by a regulator
    Preclinical volume
    Extensive
    Source independence
    Broadly replicated
    Safety characterisation
    Partial
  • Thymosin alpha-1

    Immune-modulating Short page

    Thymosin alpha-1 is a natural peptide made of 28 amino acids. It was first found in the thymus.

    Human clinical evidence
    Authorised by a regulator
    Preclinical volume
    Extensive
    Source independence
    Broadly replicated
    Safety characterisation
    Partial

In clinical development

  • Retatrutide

    Incretin (GLP-1 family)

    Retatrutide is a new drug still in testing. No country has approved it as a medicine yet.

    Human clinical evidence
    Phase III (large controlled trials)
    Preclinical volume
    Moderate
    Source independence
    A few groups
    Safety characterisation
    Partial

Experimental — not authorised in the EU, the UK or the US

  • BPC-157

    Proposed tissue repair

    BPC-157 is a lab-made chain of 15 amino acids. No country has approved it as a medicine.

    Human clinical evidence
    Case reports only
    Preclinical volume
    Extensive
    Source independence
    One group dominates
    Safety characterisation
    Uncharacterised
  • CJC-1295

    Growth-hormone axis

    CJC-1295 is a lab-made peptide. It makes the body release more growth hormone for days.

    Human clinical evidence
    Phase I (safety, small)
    Preclinical volume
    Minimal
    Source independence
    One group dominates
    Safety characterisation
    Partial
  • Ipamorelin

    Growth-hormone axis

    Ipamorelin is a lab-made peptide. It is not an approved medicine in Europe or the US.

    Human clinical evidence
    Phase II (dose and early effect)
    Preclinical volume
    Moderate
    Source independence
    A few groups
    Safety characterisation
    Partial
  • KPV

    Immune-modulating

    KPV is a lab-made chain of three amino acids. It is the tail end of the hormone alpha-MSH.

    Human clinical evidence
    None published
    Preclinical volume
    Moderate
    Source independence
    A few groups
    Safety characterisation
    Uncharacterised
  • Melanotan II

    Melanocortin

    Melanotan II is lab-made. It copies a hormone that darkens skin. No country has approved it.

    Human clinical evidence
    Phase II (dose and early effect)
    Preclinical volume
    Extensive
    Source independence
    Broadly replicated
    Safety characterisation
    Partial
  • TB-500

    Proposed tissue repair

    TB-500 is a lab-made piece of a natural protein, thymosin beta-4. It is not an approved medicine.

    Human clinical evidence
    Case reports only
    Preclinical volume
    Moderate
    Source independence
    A few groups
    Safety characterisation
    Uncharacterised
  • AOD-9604

    Metabolic Short page

    AOD-9604 is a lab-made copy of the last part of growth hormone. It is not an approved medicine.

    Human clinical evidence
    Phase II (dose and early effect)
    Preclinical volume
    Minimal
    Source independence
    One group dominates
    Safety characterisation
    Partial
  • Epitalon

    Longevity claims Short page

    Epitalon is a lab-made chain of four amino acids. No country is known to have approved it.

    Human clinical evidence
    Phase II (dose and early effect)
    Preclinical volume
    Extensive
    Source independence
    One group dominates
    Safety characterisation
    Uncharacterised
  • GHK-Cu

    Skin and hair Short page

    GHK-Cu is a tiny peptide of three amino acids holding copper. It occurs in human blood.

    Human clinical evidence
    Phase II (dose and early effect)
    Preclinical volume
    Extensive
    Source independence
    Broadly replicated
    Safety characterisation
    Uncharacterised
  • Hexarelin

    Growth-hormone axis Short page

    Hexarelin is a lab-made chain of six amino acids. It makes the body release growth hormone.

    Human clinical evidence
    Phase II (dose and early effect)
    Preclinical volume
    Extensive
    Source independence
    A few groups
    Safety characterisation
    Partial
  • MOTS-c

    Mitochondrial Short page

    MOTS-c is a small peptide made inside our cells. It is not an approved medicine.

    Human clinical evidence
    None published
    Preclinical volume
    Extensive
    Source independence
    Broadly replicated
    Safety characterisation
    Uncharacterised
  • Selank

    Acts on the brain Short page

    Selank is a lab-made chain of seven amino acids. It is a medicine in Russia.

    Human clinical evidence
    Phase II (dose and early effect)
    Preclinical volume
    Moderate
    Source independence
    A few groups
    Safety characterisation
    Uncharacterised
  • Semax

    Acts on the brain Short page

    Semax is a lab-made chain of seven amino acids. It is a medicine in Russia.

    Human clinical evidence
    Phase II (dose and early effect)
    Preclinical volume
    Extensive
    Source independence
    A few groups
    Safety characterisation
    Uncharacterised

Other

  • NAD+ precursors

    Not a peptide Short page

    These are not peptides. NR and NMN are forms of vitamin B3 that the body turns into NAD+.

    Human clinical evidence
    Phase III (large controlled trials)
    Preclinical volume
    Extensive
    Source independence
    Broadly replicated
    Safety characterisation
    Partial

Sources

Every claim on this page links to one of these sources. Scholarly sources link to their DOI; regulatory sources to the regulator's own page.

  1. European Medicines Agency (2026). Wegovy (semaglutide): EPAR — overview and product information. Official product information ema.europa.eu — accessed 20 October 2026 ↩
  2. European Medicines Agency (2026). Mounjaro (tirzepatide): EPAR — overview and product information. Official product information ema.europa.eu — accessed 20 October 2026 ↩
  3. Jastreboff AM, Kaplan LM, Davies MJ, Wilding JPH, Ahmad NN, Murray M, et al. (2026). Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity. New England Journal of Medicine. Clinical trial doi:10.1056/NEJMoa2604169 ↩
  4. U.S. Food and Drug Administration (2026). FDA Briefing Document for BPC-157-Related Bulk Drug Substances (BPC-157 (free base) and BPC-157 acetate), Pharmacy Compounding Advisory Committee meeting, 23–24 July 2026. Regulator fda.gov — accessed 20 October 2026 ↩
  5. U.S. Food and Drug Administration (2026). FDA Briefing Document for TB-500-Related Bulk Drug Substances (TB-500 (free base) and TB-500 acetate), Pharmacy Compounding Advisory Committee meeting, 23–24 July 2026. Regulator fda.gov — accessed 20 October 2026 ↩
  6. U.S. Food and Drug Administration (2026). FDA Briefing Document for KPV-Related Bulk Drug Substances (KPV (free base) and KPV acetate), Pharmacy Compounding Advisory Committee meeting, 23-24 July 2026. Regulator fda.gov — accessed 20 October 2026 ↩
  7. European Medicines Agency (2026). Applications for new human medicines under evaluation by the CHMP — October 2026 (EMA/222468/2026). Regulator ema.europa.eu — accessed 20 October 2026 ↩
  8. European Medicines Agency (2026). Medicines (search of centrally authorised medicines and EPARs). Regulator ema.europa.eu — accessed 20 October 2026 ↩
  9. Staten-Generaal / Koninkrijk der Nederlanden (2007). Geneesmiddelenwet, artikel 61 (wie UR-geneesmiddelen mag afleveren; geen aflevering zonder recept). wetten.overheid.nl (BWBR0021505), version in force from 9 September 2025. Law wetten.overheid.nl — accessed 22 October 2026 ↩
  10. Staten-Generaal / Koninkrijk der Nederlanden (2007). Geneesmiddelenwet, artikel 40 (verbod op geneesmiddelen zonder handelsvergunning, en de uitzonderingen). wetten.overheid.nl (BWBR0021505), version in force from 9 September 2025. Law wetten.overheid.nl — accessed 22 October 2026 ↩
  11. College ter Beoordeling van Geneesmiddelen (CBG-MEB) (2026). Overzicht van goedgekeurde compassionate use programma's. Regulator cbg-meb.nl — accessed 20 October 2026 ↩
  12. College ter Beoordeling van Geneesmiddelen (CBG-MEB) (2026). Standpunt: Gebruik diabetes- en afslankmedicijnen alleen zoals ze bedoeld zijn. Regulator cbg-meb.nl — accessed 20 October 2026 ↩