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№ 044

ACE-031 (ACVR2B-Fc)

Soluble activin receptor IIB fused to Fc. Traps myostatin and related TGF-β ligands. Acceleron developed it; Phase 2 was halted in 2013 due to safety signals.

GH-axis
Evidence: Limited
Half-life
~10-15 days
Route
Subcutaneous
Cycle
Historically tested in short courses
Schedule
Once weekly to once monthly in trials
In plain English

ACE-031 was an anti-myostatin drug Acceleron tested for muscle-wasting diseases. They halted Phase 2 in 2013 because some patients developed nosebleeds and visible capillaries. Educational reference — there's no safe community protocol, just the trial history.

Status & legality
Natty?
Not natty

Anti-myostatin therapy is universally banned in tested sport.

FDA
Not approved

Not FDA approved. Acceleron halted Phase 2 in 2013 due to vascular safety signals.

Compounding
Not classified

Not formally categorized in the FDA bulks lists.

WADA
Banned (S4)

S4 myostatin inhibitors are explicitly listed.

Prescribed

Not prescribed. Development discontinued.

Who it's for

  • →Researchers studying myostatin pathway
  • →Educational reference — not for active use
  • →Followers of muscle-wasting drug development history

What to expect

  1. Week 1

    Early reports describe muscle volume increase within days.

  2. Week 4

    Trial endpoint for some Phase 1 cohorts. Safety signals emerged here.

  3. Week 8

    No long-cycle human safety data — Acceleron halted further dosing.

How it works (mechanism)

Soluble activin receptor IIB fused to immunoglobulin Fc. Acts as a decoy receptor that traps myostatin and other TGF-β superfamily ligands before they can activate native receptors on muscle cells, removing the brake on muscle growth.

Dosing protocol

Trial doses ranged 1-3 mg/kg. No safe community-use dose exists. Safety signals (epistaxis, telangiectasias) led to halt.

Stacks well with

Not stacked — historical research compound only

Side effects

01Epistaxis (nosebleeds) — Phase 2 signal that halted development
02Telangiectasias (dilated capillaries near skin)
03Headache
04Theoretical: cardiac and tendon issues with strong myostatin suppression

When NOT to use

  • ⚠All — no current safe-use protocol exists
  • ⚠Pregnancy / nursing
  • ⚠Active malignancy

Bloodwork to monitor

  • • CBC if researching
  • • BUN / creatinine

Common mistakes

  • • Treating it as a drop-in Follistatin replacement (different mechanism, much longer half-life)
  • • Ignoring the halt history
  • • Assuming community-vendor product matches Acceleron's clinical material

Educational only. User-specific dosing is between you and a qualified provider.

Frequently asked

What is ACE-031 (ACVR2B-Fc)?+
ACE-031 was an anti-myostatin drug Acceleron tested for muscle-wasting diseases. They halted Phase 2 in 2013 because some patients developed nosebleeds and visible capillaries. Educational reference — there's no safe community protocol, just the trial history.
Is ACE-031 (ACVR2B-Fc) FDA approved?+
Not FDA approved. Acceleron halted Phase 2 in 2013 due to vascular safety signals.
Is ACE-031 (ACVR2B-Fc) banned by WADA?+
ACE-031 (ACVR2B-Fc) is on the WADA prohibited list under Banned (S4). S4 myostatin inhibitors are explicitly listed.
Are you still natty after taking ACE-031 (ACVR2B-Fc)?+
No. Anti-myostatin therapy is universally banned in tested sport.
Do doctors prescribe ACE-031 (ACVR2B-Fc)?+
Not prescribed. Development discontinued.
What's the typical dose of ACE-031 (ACVR2B-Fc)?+
Trial doses ranged 1-3 mg/kg. No safe community-use dose exists. Safety signals (epistaxis, telangiectasias) led to halt.
What are the side effects of ACE-031 (ACVR2B-Fc)?+
Common side effects include: Epistaxis (nosebleeds) — Phase 2 signal that halted development; Telangiectasias (dilated capillaries near skin); Headache; Theoretical: cardiac and tendon issues with strong myostatin suppression. Less common effects and full safety details are on the entry page.
How long until ACE-031 (ACVR2B-Fc) starts working?+
Early reports describe muscle volume increase within days.

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