Peptide supplier checklist

• A certificate of analysis (COA) for your batch. It should show the lot number, the test date and the lab that did the testing. A generic COA with no lot number doesn't tell you anything about the vial in your hand.
• The lot number on the COA matches the one on the vial. If the vial has no lot number, there's nothing to match.
• Independent testing. Results from a named third-party lab carry more weight than the seller's own. Some labs let you look a report up on their site.
• What was tested. Purity (usually by HPLC) says how much of the powder is the main compound; identity (usually by mass spectrometry) says it's the right compound. For anything meant to be injected, sterility and endotoxin testing matter too, and many research-grade products don't claim them.

• The compound's name and the amount in the vial.
• A lot number and a manufacture or expiry date.
• How to store it.

Peptides usually ship as freeze-dried powder, which is more stable than liquid, but heat and light still break them down. Check how products are packed and how long they're in transit. Once mixed with water, follow the storage on the label or the paperwork, and note the date you mixed it.

• A real way to contact them, and an answer when you do.
• A written returns or refund policy.
• Where products ship from, and clear prices including shipping.

Rules differ by country. Many peptides are sold “for research use only” and aren't approved medicines. Some, like semaglutide and tirzepatide, are prescription medicines, and buying them outside a pharmacy can be illegal as well as risky. Check the rules where you live, and talk to a clinician.

• No COA, or one without a lot number or a named lab.
• Only the seller's own testing.
• Health claims or dosing instructions on a product sold for research use.
• Prices far below everyone else's.
• Countdown timers and pressure to buy now.
• Payment only by crypto, gift cards or bank transfer, with no buyer protection.
• No address, no returns policy, no reply to questions.

In Dosaly, each vial has fields for the lot number, where it came from, the date you mixed it, the expiry and how it's stored, so the paperwork stays with what you're tracking. Dosaly never suggests where to buy anything.