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Are peptides safe? It depends on which of the four kinds you mean.

Peptide Chooser editorial team. Checked 2 Nov 2026.

Short answer

It depends on the kind. Approved peptide medicines have trial data the FDA reviewed; pharmacy-made and research-use peptides do not.12 Cosmetic peptides are legal to sell without approval and nobody has to show that they work.3

What are the four kinds of peptide?

A peptide is a short chain of amino acids. The same word covers four very different things you can buy in the US:

  • Approved medicines. Semaglutide (Wegovy), tirzepatide (Zepbound) and bremelanotide (Vyleesi) are peptides the FDA approved for a stated use, on prescription.678
  • Pharmacy-made (compounded) peptides. A pharmacy mixes them on a prescription. They are not FDA approved.2
  • Cosmetic peptides. Creams and serums with peptides such as GHK-Cu or Matrixyl. Cosmetics are regulated, but they do not need FDA approval to be sold.3
  • Research-use peptides. Vials sold online "for research" or "not for human use", such as BPC-157. No approved product exists.9

What safety data does each kind have?

Approved medicines have the most. Before approval the maker tests the medicine in people, usually in two well-designed trials, and the FDA reviews the data. It approves the medicine only if the benefits outweigh the known and possible risks for the people it is meant for.1 The label then lists the side effects found.

Pharmacy-made peptides have none of their own. The FDA does not check their safety, how well they work or their quality before they are sold.2 Large pharmacies registered as outsourcing facilities must follow federal manufacturing rules and the FDA inspects them; regular pharmacies are mainly overseen by state boards of pharmacy.2

For pharmacy-made semaglutide and tirzepatide, the FDA has counted 990 reports of side effects linked to compounded semaglutide and more than 730 linked to compounded tirzepatide, as of 31 May 2026. It also says these numbers are likely too low, because most pharmacies do not have to report them.4

Cosmetic peptides are judged as cosmetics: they must be safe to use on skin as labelled, but nobody has to prove that they do what the jar says.3

Research-use peptides have the least. Most have animal or cell studies only, and nobody has checked what is in a given vial. For BPC-157, the FDA says it found little or no safety information for use in people.10

What does a lab report (COA) show?

A certificate of analysis, or COA, is a lab report for one batch. It can show how pure the powder is and whether it is the peptide on the label. It cannot show that the peptide is safe or that it works in people, and it says nothing about the next batch.

Read more in our guide on how to read a peptide COA.

What is an FDA warning letter?

A warning letter is the FDA's formal notice to a company that it found what it believes are serious breaks of the law, such as poor manufacturing, claims a product cannot back up, or wrong directions for use.11 Our letters page lists 172 of them sent to peptide sellers, compounders and online clinics, 20 of them to research-use shops.5

A letter is not a court ruling. Our guide on what an FDA warning letter means explains what happens after one.

How do we show safety on this site?

Every option on our goal pages carries one of four labels: FDA approved, Cosmetic, Not FDA approved, pharmacy-made, or Not approved. We never call a research-use peptide safe, because nobody has the data to say so.

For shops we show facts, not grades: five checks (Lab reports, No FDA letter, Company found, Legal pages, Fresh prices) and the listing's own lab report. A shop that meets all five still sells a product that is not approved.

What should you ask before you buy?

  • Which of the four kinds is it: approved, pharmacy-made, cosmetic or research-use?
  • If it is a medicine, who prescribes it, and which pharmacy makes or sells it?
  • Is there a lab report for this batch, from a lab outside the shop?
  • Has the seller had an FDA warning letter? Our letters page lists the ones we know.
  • Is there an FDA-approved option for the same goal? Our goal pages put it next to the peptides.

None of this is medical advice. If you are thinking about any of these products, talk to a doctor first.

What to do next

Compare by goalSee FDA warning letters

Sources

  1. FDA, Development and Approval Process: Drugs: https://www.fda.gov/drugs/development-approval-process-drugs
  2. FDA, Compounding and the FDA: Questions and Answers: https://www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers
  3. FDA, FDA Authority Over Cosmetics: How Cosmetics Are Not FDA-Approved, but Are FDA-Regulated: https://www.fda.gov/cosmetics/laws-regulations/fda-authority-over-cosmetics-how-cosmetics-are-not-fda-approved-are-fda-regulated
  4. FDA, FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss, current as of 1 Oct 2026: https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss
  5. Peptide Chooser, FDA warning letters to peptide sellers, compounders and online clinics, checked 2 Nov 2026
  6. FDA press release, 4 Jun 2021: FDA Approves New Drug Treatment for Chronic Weight Management, First Since 2014 (Wegovy): https://www.fda.gov/news-events/press-announcements/fda-approves-new-drug-treatment-chronic-weight-management-first-2014
  7. FDA press release, 8 Nov 2023: FDA Approves New Medication for Chronic Weight Management (Zepbound): https://www.fda.gov/news-events/press-announcements/fda-approves-new-medication-chronic-weight-management
  8. FDA press release, 21 Jun 2019: FDA approves new treatment for hypoactive sexual desire disorder in premenopausal women (Vyleesi): https://www.fda.gov/news-events/press-announcements/fda-approves-new-treatment-hypoactive-sexual-desire-disorder-premenopausal-women
  9. Drugs@FDA database (no approved product for retatrutide, PT-141 shop versions, Melanotan II, CJC-1295, ipamorelin or sermorelin on 30 Oct 2026): https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm
  10. FDA, Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks, current as of 22 Apr 2026: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
  11. FDA, About Warning and Close-Out Letters, current as of 20 Mar 2024: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/about-warning-and-close-out-letters