Evidence review: Open Peptide Project (verified against primary PubMed, ClinicalTrials.gov & FDA records) · Last checked 2026-10-26. ← Back to Evidence Library

ACE-031 (ramatercept): what the evidence says

Name: ACE-031 (ramatercept)
Published: 2026-10-26

At a glance

What it is: a lab-made fusion protein (the outside part of the activin type IIB receptor joined to an antibody Fc tail) that soaks up myostatin and related muscle-limiting signals. Made by Acceleron. ^{R1, R2}

What the evidence says: one shot raised lean mass 3.3% and thigh muscle 5.1% at day 29 in 48 postmenopausal women (top amount only). ^R1 A trial in boys with Duchenne muscular dystrophy was stopped over nosebleeds and small dilated blood vessels (telangiectasias); benefits were non-significant trends. ^{R2, R3}

Biggest risks: nosebleeds and gum bleeding, telangiectasias. Black-market "ACE-031" tested in 2025 did not contain ACE-031. ^{R2, R4}

Rating


Human Human evidence	Very limited: one single-dose trial in 48 women; one stopped DMD trial ^{R1, R2}
Animal Animal / lab evidence	Muscle growth in mice and marmosets ^{R5, R6}
Regulatory	Never approved, development stopped · not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page · WADA 2026: prohibited at all times (S4.3) ^{R7, R8, R9, R10}
Established human dose	None. Study details lists what studies used

Evidence verdict: Muscle growth in healthy people: Very limited (one single-dose trial, +3.3% lean mass) · Duchenne muscular dystrophy: Very limited, trial stopped for bleeding-vessel side effects · Bodybuilding use: No human data

This page reports what studies used. It is not dosing advice.

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

About the evidence: both human trials were company-sponsored, small and short. The marmoset and mouse work is from academic and company labs. ^{R1, R2, R6}

What is it?

Myostatin and activins limit muscle growth. ACE-031 acts as a decoy receptor for them. It is related to approved drugs in the same family (luspatercept, sotatercept) but is not one of them. ^R2 Related pages: Follistatin, IGF-1 LR3, MK-677.

Does it work?

Human Healthy women (single dose): lean mass +3.3% and thigh muscle +5.1% at day 29 at the top amount; markers suggested bone and fat effects. ^{R1, R11}
Human Duchenne boys: trends for steadier 6-minute walk distance and more lean mass vs placebo, not statistically significant; stopped early. ^R2
Animal Animals: mice gained 16% body weight and 26–46% muscle weight in 28 days; marmosets gained lean mass and strength over 14 weeks. ^{R5, R6}

Is it safe?

Human Injection-site redness in healthy women. ^R1
Human DMD trial stopped for "potential safety concerns of epistaxis and telangiectasias." ^R2
Unknown No data on repeated use in healthy adults.

Gray-market "research use only" ACE-031: extra risks

A gray-market vial has no quality control and no guarantee of identity, strength or sterility. We test retail vials blind under the Open Peptide Standard; see /tests/. A passing test covers one batch on one date and does not mean the compound is safe. A 2025 anti-doping study tested 14 black-market products: 12 contained a related protein (full-length activin receptor IIB) but none contained the actual ACE-031 fusion protein, and all 12 contained many other proteins. ^R4

What we don't know

Unknown Whether muscle gains lead to strength or function in people
Unknown What the bleeding-vessel signal means with longer use

Is it legal?

US (FDA): not approved; not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page. ^{R7, R8, R9}
Athletes: WADA 2026 S4.3 names ACE-031 under decoy activin receptors; prohibited at all times. ^R10

Study details

These are amounts researchers used, not recommendations.

Study	People / model	Route	Amount used	Follow-up	Reported	Citation
Attie 2013	48 healthy postmenopausal women	Subcutaneous, once	0.02–3 mg/kg	29+ days	Lean mass +3.3% at 3 mg/kg	PMID 23169607
Campbell 2017 (NCT01099761)	24 boys with DMD	Subcutaneous every 2–4 weeks	0.5 mg/kg every 4 weeks or 1.0 mg/kg every 2 weeks	Stopped early	Bleeding-vessel side effects	PMID 27462804, NCT01099761
Cadena 2010	Mice	Injection	UNVERIFIED amount not in abstract	28 days	Muscle weight +26–46%	PMID 20466801

Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 26, 2026)

^R1 Attie KM, et al. Muscle Nerve. 2013. PMID 23169607
^R2 Campbell C, et al. Muscle Nerve. 2017. PMID 27462804
^R3 ClinicalTrials.gov NCT01099761, Study of ACE-031 in Subjects With Duchenne Muscular Dystrophy, Acceleron, terminated (CT.gov API v2, checked Oct 26, 2026). https://clinicaltrials.gov/study/NCT01099761
^R4 Reichel C, et al. Drug Test Anal. 2025. PMID 40312924
^R5 Cadena SM, et al. J Appl Physiol (1985). 2010. PMID 20466801
^R6 Cadena SM, et al. PLoS One. 2026. PMID 41686840
^R7 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
^R8 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download
^R9 FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (content current Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
^R10 WADA. The 2026 Prohibited List, S4.3. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
^R11 ClinicalTrials.gov NCT00952887, ACE-031 in healthy postmenopausal women, completed (CT.gov API v2, checked Oct 26, 2026). https://clinicaltrials.gov/study/NCT00952887

Disclaimer

This page is for education and harm reduction, not medical advice or a recommendation to use ACE-031 (ramatercept). Talk to a clinician you trust, especially if you have a bleeding disorder, are pregnant, or are a tested athlete. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).