Peptide Primer: Approved Medicine, Pharmacy Mixes, and Lab Powders

Approved Prescription Peptides

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Your doctor writes an order for a brand pen at a local drug store. Next door, a shop pitches a custom vial with the same base name. You want to know how the two compare.

Amino acids are the small parts that form proteins. A short chain of them is a peptide. That word tells you what it is made of, not what it treats or which drug laws apply. Several peptides are FDA-approved prescription medicines, with different brand names and approved uses. Semaglutide is FDA-approved under the brand names Ozempic (injection and tablets), Rybelsus (tablets), and Wegovy (injection and tablets). Tirzepatide is FDA-approved under the brand names Mounjaro (injection) and Zepbound (injection).

Other approved prescription medicines have these names. You do not need to remember this list to check a clinic:

• Tesamorelin is sold as Egrifta.
• Bremelanotide is sold as Vyleesi.
• Setmelanotide is sold as Imcivree.
• Teriparatide is sold as Forteo.
• Liraglutide is sold as Victoza and Saxenda.
• Somatropin is human growth hormone; Humatrope was first approved in 1986.

The list shows that peptides include different medicines, not treatments for one shared goal. Ask which condition a proposed drug treats. This guide does not list each medicine’s current approved uses. FDA withdrew approval of sermorelin’s Geref products in June 2009. It later found they had not been withdrawn for safety or effectiveness reasons. The signed September 2026 record lists all sermorelin products as discontinued; there is no marketed US drug label.

Prescribing an approved drug for a use outside its label is called off-label prescribing; a clinician may legally do this. An unapproved research drug has no FDA approval; this differs from using an approved medicine outside its label.

Pharmacy Mixes After the Weight-Loss Drug Shortages

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You see an online ad claiming that custom weight-loss vials with added vitamin B are the exact same thing as brand pens.

Compounding means preparing a custom medicine. A 503A pharmacy fills a prescription for one named patient; a 503B facility makes larger batches for clinics. These names come from federal law. The FDA does not approve either kind of custom medicine or check its safety before it reaches patients. During a drug shortage, a pharmacy may briefly mix copies of a brand drug. That rule ends once supply returns. The FDA declared the tirzepatide injection shortage resolved on December 19, 2024. For tirzepatide copies, the extra time to stop production ended February 18, 2025 at pharmacies serving named patients (503A). Batch facilities serving clinics (503B) had until March 19, 2025.

February 21, 2025 was the date the FDA declared the semaglutide injection shortage resolved. Semaglutide’s announced deadlines were April 22, 2025 for patient-specific pharmacies (503A) and May 22, 2025 for batch facilities (503B). A court ruling on April 24 confirmed the 503A period had ended. As of April 1, 2026, the FDA confirmed that neither semaglutide nor tirzepatide is in shortage. Adding vitamin B12 or making a small strength change can still count as a copy. The prescriber must record a significant difference for one named patient.

Look for the full ingredient name on the bottle. If you see semaglutide sodium or semaglutide acetate, those are salt forms. Each is chemically different from the ingredient used in approved semaglutide medicines. The FDA knows of no lawful way to use those salt forms in a pharmacy mix. Trial drugs like retatrutide and cagrilintide are not FDA-approved and cannot be lawfully mixed by any pharmacy. As of September 2026, no FDA-approved generic semaglutide or tirzepatide can be sold in the US. By contrast, generic liraglutide injection is FDA-approved, and liraglutide injection remains on the federal shortage list as of September 2026.

Research Powders and Skin Products

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Someone at a gym shows you a skin cream next to a vial marked for lab use. You want to know which rules apply.

The intended use decides whether a skin product counts as a cosmetic or a drug. Even for a skin product, claims about treating disease or altering body functions put it in the drug category.

A copper peptide cream sold for looks can be a cosmetic. Claims to treat disease or change how skin works put it under drug rules. FDA has cited sellers whose research-only labels conflict with claims promoting unapproved drugs for human use.