Side-by-side · Research reference

ACE-031vsHexarelin

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

BPhase 1HUMAN-REVIEWED19/45 cited

ACE-031

ActRIIB-Fc Fusion · Phase 2 Halted

Phase 2Highest trial stage

2011Development halted

~58.4 kDaMolecular weightReichel 2025

SQ · Weekly dosing investigated

Hexarelin

Hexapeptide GHRP · Cardio-tropic

100–200 mcgPer doseSmith 1996

Phase 1Evidence levelGhigo 1997

~70 minHalf-lifeSemenistaya 2010

SQ · Multiple sites · 1–3×/day

01Mechanism of Action

Parameter

ACE-031

Hexarelin

Primary target

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

Ghrelin receptor (GHS-R1a) + cardiac CD36Smith 1996 Ghigo 1997

Pathway

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

GHS-R1a → Gαq → Ca²⁺ → GH release. CD36 engagement → direct cardio-tropic actionGhigo 1997

Downstream effect

Disinhibition of myogenic signaling, increased skeletal muscle mass and strength

Strong GH pulse + IGF-1 elevation; cardio-protective effects in animal MI modelsGhigo 1997

Feedback intact?

—

Yes initially; tachyphylaxis with chronic useGhigo 1997

Origin

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

Synthetic hexapeptide His-D-2-Methyl-Trp-Ala-Trp-D-Phe-Lys-NH₂Smith 1996

Antibody development

—

02Dosage Protocols

Parameter

ACE-031

Hexarelin

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

Phase 1 / Phase 2 trialsSmith 1996 Ghigo 1997

Half-life

Days to weeks (Fc-fusion typical kinetics)

IgG1-Fc domain confers extended circulation time.

~70 minSemenistaya 2010

Duration investigated

12–24 weeks (trial cut short)

—

Standard dose

—

100–200 mcg per injectionSmith 1996

Frequency

—

1–2× per day max (tachyphylaxis with chronic 3× daily)

Lower / starter dose

—

50 mcg per dose

Duration

—

4–8 weeks on / 4–8 weeks off (tachyphylaxis mitigation)

Reconstitution

—

Bacteriostatic water

Timing

—

Pre-sleep + fasted preferred

04Side Effects & Safety

Parameter

ACE-031

Hexarelin

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

—

Cortisol elevation

—

Modest at high dosesGhigo 1997

Prolactin elevation

—

Modest at high dosesGhigo 1997

Hunger

—

Strong appetite increase via ghrelin agonism

Tachyphylaxis

—

Receptor desensitisation with chronic dosingGhigo 1997

Cardiac effects

—

Direct cardio-tropic; potential benefit in MI but unstudied in humansGhigo 1997

IGF-1 elevation

—

Strong; monitor with chronic high-dose use

Cancer risk

—

Contraindicated in active malignancy (GH/IGF-1 axis)

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

Hexarelin

·Active malignancy
·Pregnancy / breastfeeding
·Disrupted hypothalamic-pituitary axis

Relative Contraindications

ACE-031

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

Hexarelin

·Untreated diabetes
·Severe hyperprolactinemia

05Administration Protocol

Parameter

ACE-031

Hexarelin

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.

Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL = 250 mcg per 0.1 mL.

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

SQ — abdomen or thigh. Rotate sites.

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

Pre-sleep + fasted preferred. Cycle on/off to avoid tachyphylaxis.

4. Clinical trial route

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

Lyophilised: room temp, light-protected. Reconstituted: refrigerate ≤30 days.

5. Needle

—

29–31G, 4–8 mm insulin syringe.

06Stack Synergy

ACE-031

— no documented stacks

Hexarelin

+ CJC-1295 (no DAC)

Strong

View CJC-1295 (no DAC) →

Hexarelin (GHRP) + CJC-1295-no-DAC (GHRH analogue) is the higher-amplitude variant of the standard GHRH+GHRP stack. Hexarelin produces a stronger pulse than ipamorelin but with cortisol + prolactin signal — choose this stack for maximum GH amplitude when side-effect tolerance is acceptable. Cycle aggressively.

Hexarelin: 100 mcg SQ · pre-sleep
CJC-1295 (no DAC): 100 mcg SQ · same injection
Primary benefit: Maximum GH pulse amplitude (with side-effect signal)

Smith 1996 Teichman 2006