Legal status · United States
Is B7-33 legal in the United States?
No. B7-33 is not an approved medicine in the United States; its classification is "Not approved; sold 'for research use only'". Nothing containing it is authorized for any use in people. Vials labeled "for research use only" are not exempt: that label does not make human use lawful. Human evidence: Preliminary.
B7-33 in the United States at a glance
| Classification | Not approved; sold 'for research use only' |
|---|---|
| FDA approval status | Not approved |
| Evidence level | Preliminary (research strength: Preliminary) |
| Reviewed | Sep 2026 |
Classification and note come from the B7-33 profile, checked against U.S. Food and Drug Administration (FDA) listings at the reviewed date.
What this means
- 01
No product containing B7-33 is approved by FDA for any use in the United States, so nothing on the market is authorized for people.
- 02
"Research use only" is a vendor label, not a legal category that permits human use. It does not exempt a product from medicines law.
- 03
Importing, supplying or promoting it for human use can fall under medicines legislation in the United States. This page is general information, not legal advice.
What B7-33 is
A simplified relaxin analog that activates the RXFP1 receptor with a bias toward anti-fibrotic signaling; animal and cell data only.
Relaxin is a hormone with anti-fibrotic effects but is hard to manufacture. B7-33 is a single-chain derivative that reproduced relaxin's anti-fibrotic actions in animal models of heart and lung fibrosis without the receptor-desensitizing cAMP signaling.
Mechanism: Functionally selective RXFP1 agonism biased toward pERK-mediated anti-fibrotic signaling.
Regulatory history: Not approved
How FDA treats this kind of product
Approves prescription drugs by indication and polices unapproved products, including peptides sold online. Compounding pharmacies may prepare some compounds under a prescription when the FDA places them on a permitted bulk-substances category.
The classification above is the The Longevity Archive reading of U.S. Food and Drug Administration listings for B7-33 at the reviewed date, not a legal opinion. Rules change, and importing, prescribing and possessing a compound can each be treated differently. Check the regulator directly before acting on anything here.
B7-33 in other countries
Frequently asked questions
Is B7-33 legal in the United States?
No. B7-33 is not an approved medicine in the United States; its classification is "Not approved; sold 'for research use only'". Nothing containing it is authorized for any use in people. Vials labeled "for research use only" are not exempt: that label does not make human use lawful. Human evidence: Preliminary.
Can I buy B7-33 in the United States?
No approved product exists to buy. In the United States B7-33 is classified as "Not approved; sold 'for research use only'", so there is no licensed pharmacy product. Vendors selling it "for research use only" are not selling it for human use, and that label does not change its legal status. This site does not list or recommend vendors.
Is B7-33 FDA approved?
No. FDA status: Not approved. Current US classification: "Not approved; sold 'for research use only'". Evidence level: Preliminary.
Related compounds in the United States
Full research profile
Mechanism, cited studies, FDA status and the full legal summary for B7-33 live on its compound profile.
B7-33 profileThis page is general information about the regulatory status of B7-33 in the United States, current as of Sep 2026. It is not legal advice, and classifications change; check U.S. Food and Drug Administration directly or consult a lawyer for a specific situation. Educational use only. This database summarizes published research. It is not medical advice and contains no dosing protocols or recommendations for personal use. The Longevity Archive has no vendor relationships and does not recommend where to buy anything.