Side-by-side · Research reference

HexarelinvsPEG-MGF

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

APhase 1HUMAN-REVIEWED19/45 cited

BAnimal-MechanisticHUMAN-REVIEWED2/69 cited

Hexarelin

Hexapeptide GHRP · Cardio-tropic

100–200 mcgPer doseSmith 1996

Phase 1Evidence levelGhigo 1997

~70 minHalf-lifeSemenistaya 2010

SQ · Multiple sites · 1–3×/day

PEG-MGF

IGF-1Ec Splice Variant · PEGylated

~2 hrHalf-life (PEG)

~7 minNative MGF t½

IGF-1EcSplice variant

SQ · Research Protocol

01Mechanism of Action

Parameter

Hexarelin

PEG-MGF

Primary target

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

IGF-1 receptor on muscle satellite cells and myocytes

Pathway

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

IGF-1R → PI3K/Akt → mTOR activation → Satellite cell proliferation & myoblast fusion

Downstream effect

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

Satellite cell activation, muscle fiber repair, localized hypertrophy signaling

Feedback intact?

Yes initially; tachyphylaxis with chronic useGhigo 1997

Partially bypassed — does not require hepatic IGF-1 synthesis

Origin

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

IGF-1Ec splice variant (exon 4–6) conjugated to polyethylene glycol for extended circulation

Antibody development

—

Unknown — no long-term human immunogenicity data

02Dosage Protocols

Parameter

Hexarelin

PEG-MGF

Standard dose

100–200 mcg per injectionSmith 1996

—

Frequency

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

Post-training or daily

Timing to match endogenous MGF pulse post-exercise.

Lower / starter dose

50 mcg per dose

—

Evidence basis

Phase 1 / Phase 2 trialsSmith 1996 Ghigo 1997

Animal / mechanistic

Duration

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

—

Reconstitution

Bacteriostatic water

Sterile bacteriostatic water

Lyophilized form; store reconstituted at 2–8 °C.

Timing

Pre-sleep + fasted preferred

Within 30–60 min post-training

Aligns with endogenous MGF window.

Half-life

~70 minSemenistaya 2010

~2 hours (PEGylated)

Native MGF: ~7 min; PEGylation extends circulation.

Research dose range

—

100–200 mcg

Extrapolated from animal models; no validated human protocols.

PEG molecular weight

—

Typically 5–30 kDa

Higher MW = longer t½, greater steric hindrance.

03Metabolic / Fat Loss Evidence

Parameter

Hexarelin

PEG-MGF

Primary target

—

Muscle tissue (satellite cells, myocytes) — not adipose-specific

Indirect metabolic effect

—

IGF-1 signaling may modulate insulin sensitivity and lipid metabolismRen 2015

Mechanism distinct from direct lipolytic peptides.

Body composition

—

Lean mass preservation / hypertrophy focus

Fat loss evidence

—

No direct human or animal RCT data for PEG-MGF-driven fat reduction

04Side Effects & Safety

Parameter

Hexarelin

PEG-MGF

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)

IGF-1 axis stimulation contraindicated in active malignancy

Pregnancy / OB

Avoid

—

Injection site reaction

—

Erythema, induration (common with SQ peptides)

Hypoglycemia risk

—

IGF-1 axis activation can lower blood glucose

IGF-1R overstimulation

—

Theoretical risk of aberrant cell proliferation with chronic supraphysiological exposure

Fluid retention

—

Possible with IGF-1 pathway activation (dose-dependent)

PEG accumulation

—

Chronic high-dose PEGylated proteins may accumulate in tissues; clearance slower in renal impairment

Antibody formation

—

PEGylated proteins can elicit anti-PEG antibodies (neutralizing potential unknown)

Human safety data

—

Absent — no published human trials for PEG-MGF

Absolute Contraindications

Hexarelin

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

PEG-MGF

·Active malignancy or history of cancer (IGF-1R proliferative signaling)
·Known hypersensitivity to PEGylated compounds
·Pregnancy / lactation (no reproductive toxicity data)

Relative Contraindications

Hexarelin

·Untreated diabetes
·Severe hyperprolactinemia

PEG-MGF

·Diabetes (monitor glucose closely)
·Renal impairment (PEG clearance reduced)
·Retinopathy (IGF-1 axis effects on vascular proliferation)

05Administration Protocol

Parameter

Hexarelin

PEG-MGF

1. Reconstitution

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

Add 1–2 mL bacteriostatic water to lyophilized vial. Swirl gently — do not shake. Solution should be clear to slightly opalescent.

2. Injection site

SQ — abdomen or thigh. Rotate sites.

Subcutaneous — abdomen or thigh. Rotate sites to avoid lipodystrophy. Avoid areas with scar tissue or active inflammation.

3. Timing

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

Post-training preferred (within 30–60 min) to align with endogenous MGF expression window. Alternatively, daily morning dose on non-training days.

4. Storage

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

Lyophilized: room temperature, light-protected, desiccated. Reconstituted: refrigerate 2–8 °C, use within 14–21 days.

5. Needle

29–31G, 4–8 mm insulin syringe.

29–31G insulin syringe, 8–12 mm length. Pinch skin fold, insert at 45° angle for subcutaneous delivery.

06Stack Synergy

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

PEG-MGF

+ BPC-157

Moderate

View BPC-157 →

BPC-157 promotes angiogenesis and tendon/ligament repair via VEGF and growth factor modulation, while PEG-MGF targets satellite cell activation and myocyte proliferation. Complementary pathways for comprehensive tissue repair post-injury or intensive training. BPC-157's systemic stability and oral bioavailability contrast with PEG-MGF's localized IGF-1R signaling.

PEG-MGF: 100–200 mcg SQ post-training
BPC-157: 250–500 mcg SQ or oral, twice daily
Duration: 4–6 weeks (injury-dependent)
Primary benefit: Accelerated muscle and connective tissue repair, enhanced recovery

+ TB-500

Strong

View TB-500 →

TB-500 (Thymosin Beta-4 fragment) upregulates actin polymerization, cell migration, and anti-inflammatory pathways, while PEG-MGF drives satellite cell proliferation via IGF-1R/mTOR. Synergistic for muscle regeneration: TB-500 mobilizes progenitor cells, PEG-MGF stimulates their differentiation into myocytes. Both have overlapping but distinct repair cascades.

PEG-MGF: 100–200 mcg SQ post-training
TB-500: 2–5 mg SQ, 2× per week (loading), then weekly
Timing: Stagger injections by 6–12 hours
Primary benefit: Maximal satellite cell recruitment and myogenic differentiation, injury repair