Garetosmab anti-activin A antibody (150 mg vial)

In brief: ALTA PEPTIDES supplies Garetosmab (Anti-activin A monoclonal antibody, REGN2477) as a 150 mg vial of research-grade antibody for £17,999.00 (£119.99/mg), with the certificate for the current lot pending publication, held in UK stock and dispatched the same working day before 1pm. Supplied for laboratory research only, not for human consumption.

New to Garetosmab? Read our guide, Garetosmab: Regeneron's anti-activin A antibody, from FOP to the obesity triplet, for what it is, what the research covers and how it is handled.

What is garetosmab?

Garetosmab (REGN2477) is a fully human IgG4 monoclonal antibody that binds and neutralises activin A, a member of the TGF-beta superfamily. In muscle, activin A signals through the activin type II receptors to limit growth, like myostatin. In fibrodysplasia ossificans progressiva (FOP), a rare disorder caused by mutations in the ACVR1 receptor, Regeneron scientists found that activin A activates the mutant receptor and triggers bone formation in muscle, tendon and ligament. Removing activin A is meant to stop that new bone from forming.

What the research covers

In the phase 3 OPTIMA trial in 63 adults with FOP, garetosmab reduced new heterotopic bone lesions by 94% and 90% against placebo at the two levels tested over 56 weeks, with no deaths, and the FDA approved the originator product for adults with FOP in August 2026. The earlier phase 2 LUMINA-1 trial recorded five deaths among 44 participants in its open-label period; the investigators judged them unlikely to be related but could not exclude causality. In obesity, garetosmab has been tested only as the third component of the COURAGE triplet with trevogrumab and semaglutide, which preserved the most lean mass but had a 30.9% discontinuation rate. Our garetosmab article covers both programmes in detail.

Research-grade antibody, not the originator product

The vial is a research-grade antibody: a recombinant monoclonal antibody produced by a third-party manufacturer for laboratory use, not the originator company's product and not an approved biosimilar; the originator product is not sold outside clinical trials or prescription supply. It is supplied with the manufacturer's certificate of analysis for the lot, and identity and purity for an antibody are shown by methods such as SEC-HPLC and SDS-PAGE rather than the reversed-phase HPLC used for peptides. Check the certificate against the lot number on your vial before any work begins.

Buying garetosmab in the UK

Garetosmab is approved in the United States for one rare disease and is not licensed anywhere for any other use. It is not a licensed medicine in the UK and is not a controlled substance. %BRAND% supplies it strictly as a laboratory reagent for in-vitro research; it is not for human or veterinary use, and nothing on this page is guidance on using it in a person. At 150 mg per vial it is a specialist reagent priced accordingly; the stack discount does not apply to antibodies.

Garetosmab price (UK)

Prices include VAT. Shipping is £4.95 by Royal Mail Tracked 48, free on orders over £75, and sealed items can be returned within 14 days. Ships from UK stock with the lot certificate for the vial you receive.

Quality and testing

Every lot of Garetosmab is released with its certificate of analysis published on our certificates page against the lot number on the vial label. The certificate for the current lot is pending publication, and ALTA's own independent third-party test of the lot is pending; both are added to the certificates page as they arrive. Specification: Per lot certificate of analysis (identity, purity by SEC-HPLC or SDS-PAGE), supplied as research-grade monoclonal antibody, 150 mg per vial.

Handling a monoclonal antibody

Garetosmab is a monoclonal antibody, a folded protein of roughly 150 kDa, and is far less robust than a small synthetic peptide. Keep the vial at the temperature stated on the manufacturer's label and certificate, protected from light, and avoid repeated freezing and thawing. Never shake or vortex: agitation and air-liquid interfaces cause antibodies to aggregate. Use low-protein-binding plasticware, work aseptically, and if the vial is supplied lyophilised, reconstitute it only with the diluent and volume given on the manufacturer's certificate (for antibodies this is normally sterile water, not bacteriostatic water), swirling gently until dissolved. Aliquot for single use rather than re-entering the vial. As stated on the manufacturer's label and certificate; antibodies are normally held at 2 to 8 °C, protected from light and not frozen. Do not shake.

Lot traceability

Every Garetosmab vial carries a printed lot number and expiry. The same lot number appears on the certificate of analysis for that lot on our certificates page, which names who issued it (the manufacturer's QC laboratory for a batch certificate, or the outside laboratory for a third-party report) so it can be checked directly. ALTA's own independent test of each lot is published on the same row as it arrives. If the number on your vial does not match a certificate on our site, contact support before using it. Certificates are kept online for the life of the product plus two years.

Related products

Trevogrumab, Apitegromab, Bimagrumab, and everything else in Myostatin Antibodies or the full range.

Related reading in the Journal

• Garetosmab: Regeneron's anti-activin A antibody, from FOP to the obesity tripletGaretosmab is Regeneron's antibody against activin A, approved by the FDA in August 2026 for adults with fibrodysplasia ossificans progressiva after the phase 3 OPTIMA trial cut new bone lesions by 90% or more. It is also the third component of the COURAGE obesity triplet, where it improved body composition but was linked to high discontinuation and two deaths. What the trials report.
• Trevogrumab and garetosmab: the COURAGE results, side effects, and when they could be availableTrevogrumab (REGN1033) is Regeneron's fully human antibody against myostatin (GDF8). In the phase 2 COURAGE trial it prevented about half of the lean mass lost on semaglutide, and with garetosmab added it prevented more, at the cost of far more discontinuations and two deaths in the triplet arm. The figures, the safety record and where it stands.
• Myostatin inhibitors explained: the pathway, the antibodies and why muscle matters in GLP-1 weight lossA myostatin inhibitor is anything that blocks the signal telling muscle to stay small. Four monoclonal antibodies are now in trials alongside GLP-1 drugs to stop the muscle loss that comes with rapid weight loss. What the pathway is, what each antibody does, what came before, and why none of them is available outside a clinical trial.

Handling and buying guides: How to reconstitute peptides: a laboratory guide, How to store peptides, and how long lyophilised peptides last at room temperature, How to read a peptide certificate of analysis.

Handling and storage

As stated on the manufacturer's label and certificate; antibodies are normally held at 2 to 8 °C, protected from light and not frozen. Do not shake.