“Peptide” describes a molecule’s size. It says nothing about safety. Insulin is a peptide. So is a vial sold online as “research use only.”
So the question has to be asked four ways. Is it approved? Is it compoundable? Is it research-only? Where did this vial come from? What a peptide is, chemically, is covered in what are peptides.
| Tier | Example | Safety record |
|---|---|---|
| FDA-approved | Wegovy, Vyleesi | Label from controlled trials |
| Compoundable | Sermorelin, NAD+ | Ingredient reviewed; finished product not approved |
| Research-only | BPC-157, ipamorelin | Little or no human data |
| Unregulated online | Unlabeled vials | Unknown contents |
Step 1: Is it approved?
An approved peptide has a label. The label lists side effects measured in trials. That is the best safety record any peptide has.
Semaglutide, sold as Wegovy, shows what that looks like. In its weight trials, 44% of patients on 2.4 mg had nausea, against 16% on placebo [4]. Side effects led 6.8% on the drug to stop, against 3.2% on placebo.
Its label also carries a boxed warning. Semaglutide caused thyroid C-cell tumors in rodents. Whether it does so in humans is unknown [4].
PT-141, sold as Vyleesi, has its own list. Nausea affected 40% of patients [5]. Blood pressure rose briefly after each dose, by up to 6 mmHg systolic. About 1% developed darkened patches of skin.
These are real risks. They are also known, counted and printed. That is what approval buys.
Step 2: Is it compoundable?
A compounding pharmacy may make some peptides that are not approved products. The ingredient must meet FDA rules. The finished product is not FDA-approved.
NAD+ and glutathione are in 503A Category 1, the list of substances under evaluation [6]. Sermorelin qualifies because it was a component of an approved drug [8]. Its record is in sermorelin side effects.
Category 1 is a regulatory status. It is not a finding that the substance is safe or effective.
Step 3: Is it research-only?
Many popular peptides sit on no approved list. The FDA keeps a page of bulk substances with significant safety concerns [7].
For BPC-157, the FDA says it lacks the information to know whether it would harm people. For MOTS-c and TB-500, it found no human exposure data at all [7].
For ipamorelin, it cites a published study with serious adverse events, including death, given by vein [7]. For ibutamoren, it cites a trial stopped early for a heart failure signal.
The details are in BPC-157 side effects and ipamorelin side effects.
Step 4: Where did the vial come from?
The same molecule can be safe from one source and unsafe from another. Purity and sterility decide much of it.
One study bought semaglutide from illegal online pharmacies [1]. Three vials arrived. Their purity ranged from 7.7% to 14.37%, against 99% claimed on the label.
All three contained bacterial endotoxin. The three prefilled pens ordered never arrived [1].
How to check any peptide
Four questions apply to any peptide a prescriber or seller offers.
- Is there an FDA label? If so, read its warnings section.
- If compounded, is the ingredient approved or on 503A Category 1?
- Is it on the FDA’s safety-risk page? If so, read the stated risk.
- Does a licensed pharmacy dispense it on a prescription?
The legal side of each tier is in are peptides legal. Each prescribing seller we have read is written up in the seller reviews.
By goal, the options with human data are on the weight, sexual health, longevity, recovery and sleep pages.