Regulation
Investigational vs Approved Peptides
Investigational, approved, discontinued and unstudied are four different states, and compounds in all four are sold side by side. How to tell them apart.
Compounds sold in the peptide market occupy at least four distinct regulatory states, and vendor copy blurs all four into a single impression of "cutting-edge science".
The four states
Approved
An FDA-reviewed product with a marketing authorisation for one or more specific indications, a published label listing warnings, contraindications and interactions, and manufacturing under pharmaceutical quality controls. Semaglutide, tirzepatide and tesamorelin are here.
Investigational
In active clinical development under regulatory oversight, with registered trials, an active sponsor and an ongoing programme. Retatrutide is the clearest current example: substantial published Phase 2 data, reported Phase 3 results, and no approval.
"Investigational" is a description of process, not of promise. It means the studies are happening. It does not mean they will succeed.
Development discontinued
A compound that was studied in humans and then stopped — because it failed an endpoint, because the safety profile was unattractive, because the commercial case collapsed, or because a company was restructured.
CJC-1295 is in this state: published Phase 1 pharmacology, then nothing. Ipamorelin is too, and in its case the reason is documented — a randomised placebo-controlled Phase 2 trial did not meet its primary endpoint.
Marketing routinely presents these compounds as "investigational", which is misleading in a specific way: it implies an active programme that would eventually produce answers. There is no such programme.
Never meaningfully studied in humans
Compounds with preclinical literature, or with very little literature at all, that have never entered a human trial. MOTS-c sits here on the research side; much of the wider research-chemical catalogue sits here with far less behind it.
Why the distinction carries weight
Attrition is the norm. Most compounds that enter clinical development never reach approval. Failure is the base rate, not the exception, and it is what clinical development is designed to detect. A compound in Phase 2 is more likely to fail than to succeed.
Discontinuation is information. When a programme stops, something was learned — about efficacy, safety or feasibility. That information often never reaches publication, which means a discontinued compound carries an invisible negative record. Treating it as merely "not yet approved" inverts the meaning of what happened.
A trial is a package. In a clinical trial, a participant receives pharmaceutical-grade material of verified identity and potency, under eligibility screening, with defined monitoring and adverse-event reporting, and with the results collected in a way that produces knowledge. Buying the same molecule online delivers exactly one component of that package — and not the most important one.
Reading the state of a compound
Three checks, in order:
- ClinicalTrials.gov — search the compound name. Note whether any trial is recruiting or active, and when the most recent record was updated. A programme with nothing after 2012 is not an active programme.
- Drugs@FDA — search the active ingredient. Approval or nothing.
- The published literature — is there a peer-reviewed report of a human trial with results, or only a review article by the people who developed the compound?
Every profile on this site records the answers to all three under Research status, using the taxonomy set out in our evidence methodology.
Continue reading
Regulation
Are Peptides FDA Approved?
Some peptides are FDA approved drugs. Most compounds sold as "peptides" are not. Here is how to tell the difference, and what approval does and does not mean.
Regulation
How FDA Drug Approval Works
From IND to NDA: the stages a peptide has to pass through to become a medicine, what each one tests, and why most compounds never finish.