Side-by-side · Research reference

ACE-031vsSemax

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

APhase 2HUMAN-REVIEWED10/44 cited

BHuman-MechanisticAUTO-DRAFTED12/39 cited

ACE-031

ActRIIB-Fc Fusion · Phase 2 Halted

Phase 2Highest trial stage

2011Development halted

~58.4 kDaMolecular weightReichel 2025

SQ · Weekly dosing investigated

Semax

Cognitive enhancer · Russian Pharma

200–600 mcg/doseIntranasalKaplan 2017

HumanMechanisticKaplan 2017

~30 minOnset

Intranasal · 2–3×/day during cognitive demand

01Mechanism of Action

Parameter

ACE-031

Semax

Primary target

Myostatin, GDF11, activin A — TGF-β superfamily ligands

BDNF / NGF expression + monoamine modulationKaplan 2017

Pathway

Soluble decoy receptor binds circulating myostatin/TGF-β ligands → prevents ActRIIB activation → SMAD2/3 pathway inhibition

↑ BDNF + NGF synthesis + 5-HT modulation → neuroplasticity + anxiolysis + cognitive enhancementKaplan 2017

Downstream effect

Disinhibition of myogenic signaling, increased skeletal muscle mass and strength

Improved memory + attention; reduced anxiety; neuroprotection in ischemiaKaplan 2017

Feedback intact?

—

Origin

Recombinant fusion protein: human ActRIIB extracellular domain + IgG1-Fc fragmentReichel 2025

Synthetic 7-AA peptide derived from ACTH(4-7) with C-terminal Pro-Gly-Pro stabilising tailKaplan 2017

Antibody development

—

02Dosage Protocols

Parameter

ACE-031

Semax

Clinical dosing

Weekly or biweekly SQ injections (exact doses undisclosed pre-halt)

Phase 2 DMD trial protocol not fully published.

—

Black market products

Variable purity; 12/14 tested products contained target protein plus contaminantsReichel 2025

SDS-PAGE revealed multiple protein bands; quality control absent.Reichel 2025

—

Evidence basis

Phase 2 trial discontinued — incomplete dataset

Human-mechanistic + Russian clinicalKaplan 2017

Half-life

Days to weeks (Fc-fusion typical kinetics)

IgG1-Fc domain confers extended circulation time.

Short plasma; CNS effect lasts ~3–6 hr

Duration investigated

12–24 weeks (trial cut short)

—

Standard dose

—

200–600 mcg / dose intranasalKaplan 2017

Frequency

—

2–3× per day during cognitive demand

Lower / starter dose

—

100 mcg / dose

Duration

—

10–14 day cycles, repeated PRN

Reconstitution

—

Pre-formulated nasal spray (commercial); research vial: bacteriostatic water

Timing

—

Morning + early afternoon

04Side Effects & Safety

Parameter

ACE-031

Semax

Epistaxis (nosebleeds)

Significant incidence in Phase 2 DMD trial — primary safety signal

—

Telangiectasia

Dilated capillaries / spider veins observed

—

Vascular abnormalities

Mechanism: ActRIIB/ALK1 pathway disruption affects vascular homeostasis

—

Injection site reactions

Local erythema, induration (biologics class effect)

—

Antibody development

Potential for anti-drug antibodies (Fc-fusion proteins); incidence not reported

—

Black market contaminants

12/14 tested products contained multiple unidentified proteins alongside ACE-031Reichel 2025

—

Nasal irritation

—

Mild burning or congestion (transient)

Sleep disruption

—

Late-day dosing may interfere with sleep

Headache

—

Uncommon, transient

Long-term safety

—

Limited Western RCT data

Pregnancy / OB

—

Avoid

Absolute Contraindications

ACE-031

·History of vascular disorders (epistaxis, telangiectasia, HHT)
·Pregnancy (TGF-β pathway critical for fetal development)
·Active malignancy (myostatin inhibition may affect tumour growth)
·Use of non-pharmaceutical grade ACE-031 (contamination risk)Reichel 2025

Semax

·Pregnancy / breastfeeding

Relative Contraindications

ACE-031

·Coagulation disorders or anticoagulant use (epistaxis risk)
·Hereditary hemorrhagic telangiectasia (HHT) family history
·Cardiovascular disease (vascular remodeling effects unknown)

Semax

·Active psychiatric instability
·Concurrent strong stimulants

05Administration Protocol

Parameter

ACE-031

Semax

1. Pharmaceutical status

ACE-031 is not FDA-approved or commercially available. Phase 2 development was discontinued in 2011 due to safety concerns. Any ACE-031 on the black market is unregulated research chemical.

Pre-formulated nasal spray (commercial) or research vial reconstituted with bacteriostatic water.

2. Black market quality

12 of 14 tested black market ACE-031 products contained the target protein but also carried multiple unidentified protein contaminants detectable by SDS-PAGE. Two products contained no ACVR2B-immunoreactive material.Reichel 2025

Intranasal — 2–3 sprays per nostril per dose. Tilt head slightly back.

3. Detection in sport

ACE-031 is prohibited under WADA S4.3 (Myostatin Inhibitors). Gel electrophoresis and Western blotting using ACVR2B-specific antibodies can detect the ~58.4 kDa protein in biological samples.Reichel 2025

Morning + early afternoon. Avoid evening (sleep disruption).

4. Clinical trial route

Phase 2 protocol used subcutaneous injections at weekly or biweekly intervals. Exact dosing protocols remain unpublished.

Refrigerate after reconstitution; light-protected.

5. Caveat

—

Cycle on/off to avoid neurochemical adaptation.

06Stack Synergy

ACE-031

— no documented stacks

Semax

+ Selank

Moderate

View Selank →

Semax (cognitive enhancer, BDNF/NGF) and Selank (anxiolytic + immune) form the canonical Russian "neuro stack" — both intranasal peptide bioregulators with complementary axes. Semax for cognitive demand; Selank for stress mitigation.

Semax: 200–600 mcg intranasal · morning + afternoon
Selank: 150–300 mcg intranasal · midday + early evening
Primary benefit: Cognitive enhancement + stress mitigation

Kaplan 2017 Zaderej 2014