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№ 044

ACE-031 (ACVR2B-Fc)

A muscle-building drug that blocks the body's brake on muscle, shelved over safety. A soluble activin receptor IIB fused to Fc that traps myostatin and related TGF-β ligands. Acceleron developed it; Phase 2 dosing was halted in 2011 over vascular safety signals (program permanently discontinued 2013).

GH-axis
Evidence: Limited

ACE-031 (ACVR2B-Fc): A muscle-building drug that blocks the body's brake on muscle, shelved over safety. A soluble activin receptor IIB fused to Fc that traps myostatin and related TGF-β ligands. Acceleron developed it; Phase 2 dosing was halted in 2011 over vascular safety signals (program permanently discontinued 2013). ACE-031 was an anti-myostatin drug Acceleron tested for muscle-wasting diseases.

FDA ⓘ
Not approved
WADA
Banned
Typical dose
Trial doses ranged 1-3 mg/kg
Half-life ⓘ
~10-15 days
Route ⓘ
Subcutaneous
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 & legalityWhat do these mean? →
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.

Looking at ACE-031 (ACVR2B-Fc)? Your next 3 steps

  1. 1Work out your exact dose

    Vial size + BAC water turns into the exact units to draw for ACE-031 (ACVR2B-Fc).

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  2. 2See what to stack & monitor

    The companion supplements and the bloodwork worth tracking on this kind of protocol.

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  3. 3Save it & ask the Coach

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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

Members only

Stacks well with

Members 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
Free, no account needed

New to ACE-031 (ACVR2B-Fc)? Grab the starter checklist.

Drop your email and we'll send the one-page first-cycle starter checklist, plus a heads-up if ACE-031 (ACVR2B-Fc) changes legal status. No account needed.

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AI Coach, live sample
Members only
is 250mcg of bpc enough for a knee injury?
For a knee, 250 mcg sub-q daily is the standard working dose and a solid place to start. The trick with BPC is consistency, give it weeks, not days. Inject close to the joint, run it 4-6 weeks, and don't drop below 200 mcg, it tends to stop cracking the threshold reliably down there. If it hasn't moved at all by week 3, that's when adding TB-500 earns its place.
how much bac water for a 10mg reta vial?
3 mL is the standard play for a 10 mg reta vial. That's 3,333 mcg/mL, clean unit math across the titration: 2 mg = 60 units, 4 mg = 120 units, 6 mg = 180 units on a 100-unit insulin syringe. Run 2 mL instead if you want fewer, more concentrated shots (5,000 mcg/mL, so 2 mg = 40 units). Since most people titrate up over ~12 weeks, 3 mL keeps the numbers cleanest.
what should i track on bloodwork for tirzepatide?
Lipid panel, ALT/AST (liver enzymes), and an A1C, baseline before you start then every 3 months. If you've got metabolic-syndrome history, add fasting glucose and insulin so you can actually watch insulin sensitivity improve. You don't need a big hormone panel for a GLP-1.

Ask the Coach anything about ACE-031 (ACVR2B-Fc) or your own stack. This is it working.

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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) legal?+
ACE-031 (ACVR2B-Fc) is not FDA-approved. It is sold by compounding pharmacies (with a prescription) and as "research only" by peptide vendors. Possession is generally not criminalized but distribution without authorization may be. Verify local laws.
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.
What can you stack with ACE-031 (ACVR2B-Fc)?+
Common pairings: Not stacked, historical research compound only. Full stacking protocol and timing on the entry page.
Where do people get ACE-031 (ACVR2B-Fc)?+
ACE-031 (ACVR2B-Fc) is most commonly sold by research-only peptide vendors and by compounding pharmacies (the latter requires a prescription). Pepdex is not a vendor, see /coa for how to verify a Certificate of Analysis before buying from any source, and /guides/scam-vendor-spotting for vendor red flags.

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