Side-by-side · Research reference
IpamorelinvsPT-141
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
APhase 1Reviewed21/57 cited
BFDA-ApprovedReviewed13/41 cited
Ipamorelin
Selective GHRP · Ghrelin Mimetic
SQ · Multiple sites · 1–3×/day
PT-141
MC4R Agonist · FDA-Approved (HSDD)
SQ · Abdomen / thigh · ≥45 min before sex
01Mechanism of Action
Parameter
Ipamorelin
PT-141
Primary target
Ghrelin receptor (GHS-R1a) on anterior pituitaryRaun 1998
Melanocortin-4 receptor (MC4R) in hypothalamusSimerly 2023VYLEESI (bremelanotide injecti 2019
Pathway
GHS-R1a binding → Gαq/11 → ↑intracellular Ca²⁺ → GH vesicle exocytosisRaun 1998Bowers 1991
MC4R agonism in paraventricular nucleus → autonomic + neuroendocrine sexual arousal pathwaysSimerly 2023
Downstream effect
GH pulse amplification, IGF-1 elevation, recovery and lipolytic effectsBowers 2002
Increased sexual desire and arousal; central rather than peripheral mechanismClayton 2015
Origin
Pentapeptide H-Aib-His-D-2-Nal-D-Phe-Lys-NH₂; rationally designed for ghrelin-receptor selectivityRaun 1998
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
Not reported in short-term studies
—
02Dosage Protocols
Parameter
Ipamorelin
PT-141
Standard dose
200–300 mcg per injectionRaun 1998
Anecdotal community range; clinical doses 1–3 mg IV in trials.
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
Once daily pre-sleep is most common; twice or thrice for advanced users.
PRN, max 8 doses / month
Lower / starter dose
100 mcg per dose
1 mg (off-label)
Evidence basis
Phase 1 + clinical practiceRaun 1998Sigalos 2018
FDA-approved (HSDD pre-menopausal women)VYLEESI (bremelanotide injecti 2019Clayton 2015
Duration
8–12 weeks on / 4 weeks off (anecdotal)
GHS-R desensitisation reported with continuous dosing.
PRN; reassess if no benefit after 8 doses
Reconstitution
Bacteriostatic water; typical 2 mL per 5 mg vial
Pre-filled commercial pen (Vyleesi). Research vial: bacteriostatic water.
Timing
Pre-sleep + fasted preferred; 30 min away from food
≥45 min before sexual activity
Half-life
~2 hoursRaun 1998
Longer than GHRP-6 (15 min); shorter than CJC-1295-DAC (~8 days).
04Side Effects & Safety
Parameter
Ipamorelin
PT-141
Hunger
Mild appetite increase via ghrelin-receptor crosstalk
—
Injection site reaction
Mild irritation possible
Erythema, mild pain
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
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
Ipamorelin
- ·Active malignancy or cancer history
- ·Pregnancy / breastfeeding
- ·Disrupted hypothalamic-pituitary axis
PT-141
- ·Uncontrolled hypertension
- ·Known cardiovascular disease (caution)
- ·Pregnancy
Relative Contraindications
Ipamorelin
- ·Untreated diabetes
- ·Severe insulin resistance
- ·Concurrent corticosteroid use (theoretical desensitisation)
PT-141
- ·Pre-existing hyperpigmentation disorders
- ·MC4R-pathway-dependent psychiatric conditions
05Administration Protocol
Parameter
Ipamorelin
PT-141
1. Reconstitution
Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL. Roll gently. Solution should be clear.
Vyleesi: pre-filled auto-injector. Research vial: 2 mL bacteriostatic water per 10 mg → 5 mg/mL.
2. Injection site
Subcutaneous, abdomen or thigh. Rotate sites. Pinch fat for shallow SQ delivery.
SQ — abdomen or thigh.
3. Timing
Pre-sleep optimal — aligns with natural GH pulse. Some protocols add a morning fasted dose.
≥45 min before sexual activity for peak effect. Effect persists ~6–8 h.
4. Storage
Lyophilised: room temp, protected from light. Reconstituted: refrigerate 2–8 °C, use within 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.
06Stack Synergy
Ipamorelin
+ Tesamorelin
StrongIpamorelin (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
+ CJC-1295 (no DAC)
StrongCJC-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
PT-141
— no documented stacks