Supply chain transparency
Where peptide API really comes from
A clear-eyed look at the shared origin of compounded and research peptides — and the regulatory wall that separates the two.
Both supply chains start at the same place
For semaglutide, tirzepatide, and most GLP-1 family peptides, the bulk active pharmaceutical ingredient (API) comes overwhelmingly from a small set of large Chinese peptide synthesis houses. This is publicly documented through FDA Drug Master File filings, which any pharmacist or buyer can look up.
The major Chinese peptide API manufacturers serving both regulated and gray channels include:
- Hangzhou Enogen BiotechFDA "Green List" for semaglutide & tirzepatide; serves 503B compounding pharmacies
- Hybio PharmaceuticalMajor peptide API manufacturer
- WuXi TIDESPeptide arm of WuXi AppTec, a major Chinese CDMO
- Sichuan Pengting TechnologyBulk peptide API producer
- Hangzhou Go Top Peptide BiotechPeptide API for export market
- Sinopep BiopharmaPeptide synthesis and API
- AmbioPharmMulti-site peptide manufacturer
- Polypeptide GroupMulti-site (Switzerland, US, and China manufacturing)
So the hypothesis that "both compounded and research peptides come from China" is largely correct. What it misses is that not all Chinese factories are equivalent.
The two-tier Chinese factory reality
There are two distinct tiers of Chinese peptide manufacturers, and the legal sourcing wall between them is the most important fact in this article.
Tier 1 — FDA-registered
- Filed a Drug Master File (DMF) with the FDA
- Registered under §510 of the Federal Food, Drug, and Cosmetic Act
- Inspected by the FDA
- API can legally enter the US drug supply chain
- 503B compounding pharmacies are legally required to source from this tier
Examples: Enogen and a small number of others on the FDA's published Green List.
Tier 2 — Unregistered
- No DMF, no §510 registration, not inspected by the FDA
- Sells bulk peptide API into the export market
- Often labeled "research use only" or "not for human consumption"
- Per a Partnership for Safe Medicines analysis of 239 illegal API shipments, a majority of Chinese "semaglutide" exporters are not permitted to distribute that API for human use even within China
Examples: Material is dramatically cheaper at the bulk level — which is why discount vendors use it.
Research-peptide vendors source from both tiers. The reputable ones — those that publish independent third-party CoAs and have visible community track records — increasingly source from Tier 1. The cheap ones don't, because Tier 2 material is dramatically less expensive at the bulk level.
The regulatory hard wall: A 503B compounding pharmacy cannot legally use Tier 2 material. That's a regulatory hard wall, not an industry preference.