What Is Peptide Therapy? A Term Covering Four Different Things

"Peptide therapy" is not a defined category. It is a marketing term covering at least four situations that differ enormously in regulation, evidence, and oversight.

Knowing which one is being described is the difference between a prescription medicine and an unregulated purchase.

The four things it can mean

All four get called peptide therapy. Only the first involves a product approved for the use it is being sold for.

Approved medicine

A small number of peptides are approved medicines with labelled indications: semaglutide and tirzepatide for weight management and diabetes, tesamorelin for HIV-associated lipodystrophy, oxytocin in obstetrics, PT-141 for one sexual-health indication.

These have characterised safety profiles, defined doses, and manufacturing oversight. They are also the minority.

Compounding

Compounding pharmacies prepare medicines from bulk substances under specific rules. This is how compounded semaglutide and tirzepatide reach patients, and it is a genuinely regulated activity — but the resulting product has not been through drug approval.

The FDA maintains lists governing which bulk substances may be used, and has separately identified substances that may present significant safety risks in compounding. See are peptides legal for how those tracks differ.

Clinics

The widest variation sits here. Some clinics prescribe approved medicines with monitoring. Others administer unapproved research compounds with a consultation attached.

Self-directed use

Buying vials online and self-administering is the fourth category and the one with no oversight at all — no assurance of identity, purity, content or sterility, and no adverse-event reporting.

The COA guide covers what can be verified, and the vendor guide what cannot.

What the term obscures

Calling all four "peptide therapy" implies a shared level of legitimacy. A recent review of performance-enhancing peptides framed the problem precisely as a gap between clinical evidence and patient self-administration — which is the gap the term papers over.

Frequently asked questions

Is peptide therapy FDA approved?

Some specific peptides are approved for specific indications. "Peptide therapy" as a category is not a regulatory designation and is not approved or unapproved as a whole.

Is compounded the same as approved?

No. Compounding pharmacies are regulated, but a compounded preparation has not been through drug approval and is not an approved product.

How do I tell which category a clinic offers?

Ask whether each specific compound is approved, compounded, or a research chemical. The answer is checkable.