Side-by-side · Research reference

ACE-031vsIpamorelin

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-REVIEWED21/57 cited

ACE-031

ActRIIB-Fc Fusion · Phase 2 Halted

Phase 2Highest trial stage

2011Development halted

~58.4 kDaMolecular weightReichel 2025

SQ · Weekly dosing investigated

Ipamorelin

Selective GHRP · Ghrelin Mimetic

200–300 mcgPer doseRaun 1998

Phase 1Evidence levelRaun 1998 Sigalos 2018

~2 hrHalf-lifeRaun 1998

SQ · Multiple sites · 1–3×/day

01Mechanism of Action

Parameter

ACE-031

Ipamorelin

Primary target

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

Ghrelin receptor (GHS-R1a) on anterior pituitaryRaun 1998

Pathway

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

GHS-R1a binding → Gαq/11 → ↑intracellular Ca²⁺ → GH vesicle exocytosisRaun 1998 Bowers 1991

Downstream effect

Disinhibition of myogenic signaling, increased skeletal muscle mass and strength

GH pulse amplification, IGF-1 elevation, recovery and lipolytic effectsBowers 2002

Feedback intact?

—

Yes — pulsatile pattern preserved; somatostatin feedback activeBowers 2002

Origin

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

Pentapeptide H-Aib-His-D-2-Nal-D-Phe-Lys-NH₂; rationally designed for ghrelin-receptor selectivityRaun 1998

Antibody development

—

Not reported in short-term studies

02Dosage Protocols

Parameter

ACE-031

Ipamorelin

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 + clinical practiceRaun 1998 Sigalos 2018

Half-life

Days to weeks (Fc-fusion typical kinetics)

IgG1-Fc domain confers extended circulation time.

~2 hoursRaun 1998

Longer than GHRP-6 (15 min); shorter than CJC-1295-DAC (~8 days).

Duration investigated

12–24 weeks (trial cut short)

—

Standard dose

—

200–300 mcg per injectionRaun 1998

Anecdotal community range; clinical doses 1–3 mg IV in trials.

Frequency

—

1–3× per day

Once daily pre-sleep is most common; twice or thrice for advanced users.

Lower / starter dose

—

100 mcg per dose

Duration

—

8–12 weeks on / 4 weeks off (anecdotal)

GHS-R desensitisation reported with continuous dosing.

Reconstitution

—

Bacteriostatic water; typical 2 mL per 5 mg vial

Timing

—

Pre-sleep + fasted preferred; 30 min away from food

04Side Effects & Safety

Parameter

ACE-031

Ipamorelin

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

—

Negligible vs other GHRPsRaun 1998

Prolactin elevation

—

NegligibleRaun 1998

Hunger

—

Mild appetite increase via ghrelin-receptor crosstalk

Injection site reaction

—

Mild irritation possible

GH excess (overdose)

—

Joint pain, edema, insulin resistance

IGF-1 elevation

—

Dose-dependent; monitor with chronic high-dose use

Cancer risk

—

Theoretical via GH/IGF-1 axis; contraindicated in active malignancy

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

Ipamorelin

·Active malignancy or cancer history
·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)

Ipamorelin

·Untreated diabetes
·Severe insulin resistance
·Concurrent corticosteroid use (theoretical desensitisation)

05Administration Protocol

Parameter

ACE-031

Ipamorelin

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. Roll gently. Solution should be clear.

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

Subcutaneous, abdomen or thigh. Rotate sites. Pinch fat for shallow SQ delivery.

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 optimal — aligns with natural GH pulse. Some protocols add a morning fasted dose.

4. Clinical trial route

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

Lyophilised: room temp, protected from light. Reconstituted: refrigerate 2–8 °C, use within 30 days.

5. Needle

—

29–31G, 4–8 mm insulin syringe.

06Stack Synergy

ACE-031

— no documented stacks

Ipamorelin

+ Tesamorelin

Strong

View Tesamorelin →

Ipamorelin (GHRP) + tesamorelin (GHRH analogue) is the textbook dual-axis GH stack. They activate two distinct pituitary receptors — the ghrelin receptor and the GHRH receptor — producing a synergistic GH pulse larger than either alone. Ipamorelin's selectivity (no cortisol/prolactin spike) makes it the ideal GHRP partner for long-term protocols.

Ipamorelin: 200–300 mcg SQ · pre-sleep
Tesamorelin: 2 mg SQ · same injection · pre-sleep
Primary benefit: Maximal GH pulsatility, fat loss, recovery, sleep depth

Raun 1998 Bowers 2002

+ CJC-1295 (no DAC)

Strong

View CJC-1295 (no DAC) →

CJC-1295 (no DAC) is a short-acting GHRH analogue. Combined with ipamorelin (GHRP), the pulse is amplified across both receptor systems with timing similar to native physiology. Without the DAC modification, the stack maintains sharp peaks rather than the sustained elevation seen with CJC-1295-DAC + ipamorelin.

Ipamorelin: 200–300 mcg SQ · pre-sleep
CJC-1295 (no DAC): 100 mcg SQ · same injection
Primary benefit: Pulsatile GH stimulation matching physiological pattern

Teichman 2006 Ionescu 2006