Side-by-side · Research reference
PT-141vsTesamorelin
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
AFDA-ApprovedReviewed13/41 cited
BFDA-ApprovedVerified27/68 cited
PT-141
MC4R Agonist · FDA-Approved (HSDD)
SQ · Abdomen / thigh · ≥45 min before sex
Tesamorelin
GHRH Analogue · FDA-Approved
SQ · Abdomen · Once Daily
01Mechanism of Action
Parameter
PT-141
Tesamorelin
Primary target
Melanocortin-4 receptor (MC4R) in hypothalamusSimerly 2023VYLEESI (bremelanotide injecti 2019
Hypothalamic GHRH receptorsEGRIFTA® (tesamorelin for inje 2010
Pathway
MC4R agonism in paraventricular nucleus → autonomic + neuroendocrine sexual arousal pathwaysSimerly 2023
GHRH → Pituitary GH release → Liver IGF-1 synthesisFalutz 2007
Downstream effect
Increased sexual desire and arousal; central rather than peripheral mechanismClayton 2015
Increased GH pulsatility, elevated IGF-1, lipolysis of visceral adipose tissueFalutz 2010
Feedback intact?
—
Yes — physiological pulsatility preserved
Origin
Cyclic 7-AA peptide derived from α-MSH (agonist Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-OH cyclic)VYLEESI (bremelanotide injecti 2019
Synthetic 44-AA GHRH analogue with trans-3-hexenoic-acid modification for stabilityEGRIFTA® (tesamorelin for inje 2010
02Dosage Protocols
Parameter
PT-141
Tesamorelin
Standard dose
1.75 mg SQVYLEESI (bremelanotide injecti 2019
Single dose ≥45 min before anticipated sexual activity. Max 1 dose / 24 hr.
2 mg / dayEGRIFTA® (tesamorelin for inje 2010
FDA-approved protocol.
Frequency
PRN, max 8 doses / month
Once daily (morning or pre-sleep)
Aligns with natural GH pulse.
Lower / starter dose
1 mg (off-label)
1 mg / dayFalutz 2010
1 mg still produces significant IGF-1 elevation.
Evidence basis
FDA-approved (HSDD pre-menopausal women)VYLEESI (bremelanotide injecti 2019Clayton 2015
RCT / FDA-approvedFalutz 2007Falutz 2010
Duration
PRN; reassess if no benefit after 8 doses
12–52 weeks
VAT returns within months of stopping.
Reconstitution
Pre-filled commercial pen (Vyleesi). Research vial: bacteriostatic water.
Sterile water per labeling
Preserved at 2–8 °C after reconstitution.
Timing
≥45 min before sexual activity
Empty stomach, pre-sleep preferred
Half-life
~26 min (plasma)EGRIFTA® (tesamorelin for inje 2010
Modified vs native GHRH (7 min t½).
03Metabolic / Fat Loss Evidence
Parameter
PT-141
Tesamorelin
Primary fat target
—
Visceral adipose tissue (VAT) — abdominal
Effect on lean mass
—
Modest lean mass preservation / slight increase
Effect reversibility
—
VAT returns within months of stopping
Key publication
—
Falutz et al. NEJM 2007 · Falutz JCEM 2010 · FDA approval 2010Falutz 2007Falutz 2010EGRIFTA® (tesamorelin for inje 2010
04Side Effects & Safety
Parameter
PT-141
Tesamorelin
Flushing
Common, transient
—
Injection site reaction
Erythema, mild pain
Erythema, pruritus, redness (common)
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
—
Fluid retention / Edema
—
Peripheral edema, arthralgia, carpal tunnel (GH-axis effect)
IGF-1 elevation
—
Dose-dependent; supraphysiological levels = discontinue
Cancer risk
—
Contraindicated in active malignancy (GH/IGF-1 axis); theoretical tumour growth riskEGRIFTA® (tesamorelin for inje 2010
Antibody formation
—
~50% at 26 weeks; non-neutralising in most; rare hypersensitivity (<1%)Sévigny 2018
GI symptoms
—
Nausea, diarrhea (mild, transient)
Absolute Contraindications
PT-141
- ·Uncontrolled hypertension
- ·Known cardiovascular disease (caution)
- ·Pregnancy
Tesamorelin
- ·Active malignancy or history of treated cancer
- ·Pregnancy
- ·Hypersensitivity to tesamorelin or mannitol
- ·Disruption of hypothalamic-pituitary axis (trauma, tumour, radiation)
Relative Contraindications
PT-141
- ·Pre-existing hyperpigmentation disorders
- ·MC4R-pathway-dependent psychiatric conditions
Tesamorelin
- ·Untreated diabetes (monitor HbA1c)
- ·Severe carpal tunnel syndrome
- ·Acute critical illness
05Administration Protocol
Parameter
PT-141
Tesamorelin
1. Reconstitution
Vyleesi: pre-filled auto-injector. Research vial: 2 mL bacteriostatic water per 10 mg → 5 mg/mL.
Add 2.1 mL sterile water to 2 mg lyophilised vial. Roll gently — do not shake. Solution should be clear.
2. Injection site
SQ — abdomen or thigh.
Subcutaneous — abdomen preferred. Rotate sites (avoid same spot within 2 cm). Avoid navel and waistband area.
3. Timing
≥45 min before sexual activity for peak effect. Effect persists ~6–8 h.
Once daily. Preferred: evening, 2–3 hrs post-meal, before sleep — aligns with natural GH secretion pulse.
4. Storage
Vyleesi: room temp ≤30 °C. Research vial: refrigerate after reconstitution.
Lyophilised: room temp, light-protected. Reconstituted: refrigerate 2–8 °C, use within 21 days.
5. Needle
Auto-injector (Vyleesi) or 29–31G, 4–8 mm insulin syringe.
27–31G, 4–8 mm insulin syringe. Pinch skin, 45° angle for lean individuals.
06Stack Synergy
PT-141
— no documented stacks
Tesamorelin
+ Ipamorelin
StrongTesamorelin (GHRH analogue) and ipamorelin (GHRP / ghrelin mimetic) act on two distinct receptor systems to amplify GH release synergistically — GHRH receptor + ghrelin receptor. This dual-axis stimulation produces a more robust, sustained GH pulse than either alone while maintaining physiological pulsatility. Ipamorelin is highly selective with minimal cortisol or prolactin elevation, making it the preferred GHRP pairing.
- Tesamorelin
- 2 mg SQ · evening
- Ipamorelin
- 200–300 mcg SQ · same injection
- Frequency
- Once daily, pre-sleep
- Primary benefit
- Maximal GH pulsatility, fat loss, recovery, sleep quality