Side-by-side · Research reference
GHRP-6vsPT-141
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
APhase 1Reviewed10/36 cited
BFDA-ApprovedReviewed13/41 cited
GHRP-6
Hexapeptide GHRP · Strong appetite stimulant
SQ · Multiple sites · 1–3×/day
PT-141
MC4R Agonist · FDA-Approved (HSDD)
SQ · Abdomen / thigh · ≥45 min before sex
01Mechanism of Action
Parameter
GHRP-6
PT-141
Primary target
Ghrelin receptor (GHS-R1a)Bowers 1990
Melanocortin-4 receptor (MC4R) in hypothalamusSimerly 2023VYLEESI (bremelanotide injecti 2019
Pathway
GHS-R1a → Gαq → Ca²⁺ → GH release; central appetite driveBowers 2002
MC4R agonism in paraventricular nucleus → autonomic + neuroendocrine sexual arousal pathwaysSimerly 2023
Downstream effect
GH pulse + strong appetite stimulation; modest IGF-1 elevationBowers 2002
Increased sexual desire and arousal; central rather than peripheral mechanismClayton 2015
Feedback intact?
—
—
Origin
Synthetic hexapeptide; first-generation GHRP from Bowers groupBowers 1990
Cyclic 7-AA peptide derived from α-MSH (agonist Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-OH cyclic)VYLEESI (bremelanotide injecti 2019
Antibody development
—
—
02Dosage Protocols
Parameter
GHRP-6
PT-141
Standard dose
100–200 mcg per injectionBowers 1990
1.75 mg SQVYLEESI (bremelanotide injecti 2019
Single dose ≥45 min before anticipated sexual activity. Max 1 dose / 24 hr.
Frequency
1–3× per day
PRN, max 8 doses / month
Lower / starter dose
50 mcg per dose
1 mg (off-label)
Evidence basis
Phase 1 + clinical practiceBowers 1990
FDA-approved (HSDD pre-menopausal women)VYLEESI (bremelanotide injecti 2019Clayton 2015
Duration
8–12 weeks on / 4 off
PRN; reassess if no benefit after 8 doses
Reconstitution
Bacteriostatic water
Pre-filled commercial pen (Vyleesi). Research vial: bacteriostatic water.
Timing
Pre-meal preferred for appetite support
≥45 min before sexual activity
04Side Effects & Safety
Parameter
GHRP-6
PT-141
Hunger
Pronounced — defining feature vs ipamorelin
—
Cortisol elevation
Mild
—
Prolactin elevation
Mild
—
Injection site reaction
Mild
Erythema, mild pain
Cancer risk
Contraindicated in active malignancy
—
Pregnancy / OB
Avoid
Contraindicated
Flushing
—
Common, transient
Headache
—
Common
Hyperpigmentation (focal)
—
Rare focal skin darkening; reversible after discontinuationVYLEESI (bremelanotide injecti 2019
Hypertension (transient)
—
Mean ↑6 mmHg systolic peaking ~4 h post-dose; resolves within 12 hVYLEESI (bremelanotide injecti 2019
Cardiovascular disease
—
Use caution; transient BP rise
Absolute Contraindications
GHRP-6
- ·Active malignancy
- ·Pregnancy / breastfeeding
PT-141
- ·Uncontrolled hypertension
- ·Known cardiovascular disease (caution)
- ·Pregnancy
Relative Contraindications
GHRP-6
- ·Severe insulin resistance (appetite-driven caloric load)
PT-141
- ·Pre-existing hyperpigmentation disorders
- ·MC4R-pathway-dependent psychiatric conditions
05Administration Protocol
Parameter
GHRP-6
PT-141
1. Reconstitution
Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL.
Vyleesi: pre-filled auto-injector. Research vial: 2 mL bacteriostatic water per 10 mg → 5 mg/mL.
2. Injection site
SQ — abdomen. Rotate sites.
SQ — abdomen or thigh.
3. Timing
Pre-meal for appetite support; pre-sleep for GH alignment.
≥45 min before sexual activity for peak effect. Effect persists ~6–8 h.
4. Storage
Lyophilised: room temp. Reconstituted: refrigerate ≤30 days.
Vyleesi: room temp ≤30 °C. Research vial: refrigerate after reconstitution.
5. Needle
29–31G, 4–8 mm insulin syringe.
Auto-injector (Vyleesi) or 29–31G, 4–8 mm insulin syringe.