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Legal status · United States

Is Relaxin-2 legal in the United States?

Written by Reviewed Sep 2026

Not approvedHormoneStudies in people cited: 3

Direct answer

No. Relaxin-2 is not an approved medicine in the United States. Its legal category is "Not a medicine; endogenous signalling molecule". Nothing that contains it is allowed for any use in people. Vials labeled "for research use only" get no exception: that label does not make them legal to use in people. On the evidence, 2 completed human trials are cited on its profile.

People given it
7,706
Found nothing
2

Legal category

Not a medicine; endogenous signalling molecule

Relaxin-2 is a hormone made by the ovary after ovulation (the corpus luteum) and by the placenta. Its lab-made copy, serelaxin, is not FDA-approved. RELAX-AHF-2 missed both of its main goals in 6,545 patients, and work on it for sudden heart failure stopped. No approved medicine acts on its receptor, RXFP1. Longer-lasting relaxin drugs such as AZD3427 are still investigational.

Reviewed Sep 2026. This is a legal category, not legal advice.

A "research use only" label on a vial does not make it legal to use on people.

Relaxin-2 in the United States at a glance

Legal categoryNot a medicine; endogenous signalling molecule
NoteRelaxin-2 is a hormone made by the ovary after ovulation (the corpus luteum) and by the placenta. Its lab-made copy, serelaxin, is not FDA-approved. RELAX-AHF-2 missed both of its main goals in 6,545 patients, and work on it for sudden heart failure stopped. No approved medicine acts on its receptor, RXFP1. Longer-lasting relaxin drugs such as AZD3427 are still investigational.
FDA approval statusRelaxin-2 is a hormone the body makes. Serelaxin, a lab-made copy of it, is not approved by the FDA or any other regulator. It drew attention after the RELAX-AHF result. But the larger follow-up study, RELAX-AHF-2, missed both of its main goals, and work on it for sudden heart failure was stopped.
Studies in people3 of 5 sources on the profile
ReviewedSep 2026

The legal category and note come from the Relaxin-2 profile. We checked them against U.S. Food and Drug Administration (FDA) listings on the reviewed date.

What this means

  • 01

    No product containing Relaxin-2 is approved by FDA for any use in the United States. So nothing on sale is allowed for use in people.

  • 02

    "Research use only" is a label sellers put on. It is not a legal category that allows use in people, and it does not get a product out of medicines law.

  • 03

    Importing it, supplying it or promoting it for use in people can fall under medicines law in the United States. This page is general information, not legal advice.

What Relaxin-2 is

The pregnancy hormone that opens up blood flow. A drug version, serelaxin, was tested in 1,161 people with sudden heart failure, and there were 42 deaths by six months on the drug against 65 on a dummy drip. But that was a side question. The bigger follow-up in 6,545 people found heart deaths of 8.7 percent on the drug and 8.9 percent without it. Serelaxin was never approved and work on it for heart failure stopped.

Relaxin-2 is a hormone made of two linked chains, from the same family as insulin. The ovary and the placenta make it.

How it works: Relaxin-2 works through a receptor called RXFP1. It widens blood vessels across the body, makes the heart pump more, sends more blood to the kidneys and makes arteries more stretchy.

Approval history: Relaxin-2 is a hormone the body makes. Serelaxin, a lab-made copy of it, is not approved by the FDA or any other regulator. It drew attention after the RELAX-AHF result. But the larger follow-up study, RELAX-AHF-2, missed both of its main goals, and work on it for sudden heart failure was stopped.

How FDA treats this kind of product

Approves prescription drugs, each for a named use. It also acts against unapproved products, including peptides sold online. Compounding pharmacies, which mix drugs to order, may make some compounds with a prescription. That only applies when the FDA puts the compound in a category of bulk ingredients it allows.

The legal category above is how The Longevity Archive reads U.S. Food and Drug Administration listings for Relaxin-2 on the reviewed date. It is not a legal opinion. Rules change. Bringing a compound into the country, prescribing it and owning it can each be treated differently. Check with the agency before you act on anything here.

Check FDA directly

Relaxin-2 in sport and the military

Whether Relaxin-2 is banned in sport is set by the World Anti-Doping Code and by military rules, not by its legal status in the United States. Before you compete or get tested, look up Relaxin-2 by name on the Prohibited List, or look up a named product in Global DRO. Under the World Anti-Doping Code, category S0 bans, at all times, any drug-like substance that meets two tests. No other section of the List covers it. And no government health regulator anywhere has a current approval for it as a treatment in people. Many substances that are approved somewhere are banned by name in another section. So approval does not mean a substance is allowed in sport.

The rules you compete or serve under decide this, not this page.

Relaxin-2 in other countries

Frequently asked questions

Is Relaxin-2 legal in the United States?

No. Relaxin-2 is not an approved medicine in the United States. Its legal category is "Not a medicine; endogenous signalling molecule". Nothing that contains it is allowed for any use in people. Vials labeled "for research use only" get no exception: that label does not make them legal to use in people. On the evidence, 2 completed human trials are cited on its profile. Note: Relaxin-2 is a hormone made by the ovary after ovulation (the corpus luteum) and by the placenta. Its lab-made copy, serelaxin, is not FDA-approved. RELAX-AHF-2 missed both of its main goals in 6,545 patients, and work on it for sudden heart failure stopped. No approved medicine acts on its receptor, RXFP1. Longer-lasting relaxin drugs such as AZD3427 are still investigational.

Can I buy Relaxin-2 in the United States?

There is no approved product to buy. In the United States, Relaxin-2 has the legal category "Not a medicine; endogenous signalling molecule". So no licensed pharmacy product exists. Sellers who list it "for research use only" are not selling it for use in people, and that label does not change its legal status. Sellers named on the price pages are ranked by certificate tier, then price, and any affiliate income is disclosed there. Naming a seller is not a recommendation to buy or use anything. Note: Relaxin-2 is a hormone made by the ovary after ovulation (the corpus luteum) and by the placenta. Its lab-made copy, serelaxin, is not FDA-approved. RELAX-AHF-2 missed both of its main goals in 6,545 patients, and work on it for sudden heart failure stopped. No approved medicine acts on its receptor, RXFP1. Longer-lasting relaxin drugs such as AZD3427 are still investigational.

Is Relaxin-2 FDA approved?

No. FDA status: Relaxin-2 is a hormone the body makes. Serelaxin, a lab-made copy of it, is not approved by the FDA or any other regulator. It drew attention after the RELAX-AHF result. But the larger follow-up study, RELAX-AHF-2, missed both of its main goals, and work on it for sudden heart failure was stopped.. Current US legal category: "Not a medicine; endogenous signalling molecule". On the evidence, 2 completed human trials are cited on its profile.

Related compounds in the United States

Full research profile

How Relaxin-2 works, the studies we cite, FDA status and the full legal summary are all on its compound profile.

Relaxin-2 profile

This page is general information about the legal status of Relaxin-2 in the United States, current as of Sep 2026. It is not legal advice. Legal status changes. For your own situation, check with U.S. Food and Drug Administration or ask a lawyer. Educational use only. This database summarizes published research and is not medical advice. Where a dose appears it is a record of what a trial or clinic ran, or what people describe doing, with its source attached. Nothing here is a recommendation for personal use. Sellers named on the price pages are ranked by certificate tier, then price, and any affiliate income is disclosed there. Naming a seller is not a recommendation to buy or use anything.