Side-by-side · Research reference

GLP-1 (7-37)vsPT-141

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

AHuman-MechanisticHUMAN-REVIEWED16/43 cited

BFDA-ApprovedHUMAN-REVIEWED13/41 cited

GLP-1 (7-37)

Incretin Hormone · Native Peptide

~2 minHalf-lifeAlavi 2021 Ding 2017

3297.7 DaMolecular weightAlavi 2021

1922Discovery year

Research use only · IV/SC in experimental settings

PT-141

MC4R Agonist · FDA-Approved (HSDD)

1.75 mgPer doseVYLEESI (bremelanotide injecti 2019

Pre-sexTimingVYLEESI (bremelanotide injecti 2019

~2.7 hrHalf-lifeVYLEESI (bremelanotide injecti 2019

SQ · Abdomen / thigh · ≥45 min before sex

01Mechanism of Action

Parameter

GLP-1 (7-37)

PT-141

Primary target

GLP-1 receptor (class B GPCR)Koole 2015

Melanocortin-4 receptor (MC4R) in hypothalamusSimerly 2023 VYLEESI (bremelanotide injecti 2019

Pathway

GLP-1R activation → cAMP production → PKA signaling → insulin secretion (pancreatic β-cells)Lu 2025 Koole 2015

MC4R agonism in paraventricular nucleus → autonomic + neuroendocrine sexual arousal pathwaysSimerly 2023

Downstream effect

Glucose-dependent insulin release, glucagon suppression, delayed gastric emptying, reduced food intakeLu 2025 Ding 2017

Increased sexual desire and arousal; central rather than peripheral mechanismClayton 2015

Feedback intact?

Yes — physiological secretion and degradation preserved

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Origin

Endogenous peptide cleaved from proglucagon in intestinal L cells; secreted postprandially

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

GLP-1 (7-37)

PT-141

Clinical use

None — native GLP-1 not used therapeutically

Engineered analogues (semaglutide, liraglutide) used clinically.Friedman 2024

—

Research dosing

Variable — 0.1–10 nmol/kg in animal models

Used as reference standard for analogue comparison.

—

Half-life

~2 minutes (plasma)Alavi 2021 Ding 2017

Requires continuous infusion for sustained effect.

~2.7 hrVYLEESI (bremelanotide injecti 2019

Modified analogues

t½ extended to 13 h (liraglutide), 165 h (semaglutide)

Via DPP-4 resistance + fatty acid acylation.

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Standard dose

—

1.75 mg SQVYLEESI (bremelanotide injecti 2019

Single dose ≥45 min before anticipated sexual activity. Max 1 dose / 24 hr.

Frequency

—

PRN, max 8 doses / month

Lower / starter dose

—

1 mg (off-label)

Evidence basis

—

FDA-approved (HSDD pre-menopausal women)VYLEESI (bremelanotide injecti 2019 Clayton 2015

Duration

—

PRN; reassess if no benefit after 8 doses

Reconstitution

—

Pre-filled commercial pen (Vyleesi). Research vial: bacteriostatic water.

Timing

—

≥45 min before sexual activity

03Metabolic / Fat Loss Evidence

Parameter

GLP-1 (7-37)

PT-141

Mechanism

GLP-1R activation in hypothalamic satiety centers (arcuate nucleus) reduces food intakeLu 2025

Effect demonstrated with long-acting analogues (liraglutide).Lu 2025

—

Native GLP-1 efficacy

Minimal — rapid degradation prevents sustained appetite suppression

—

Gastric emptying

Delayed in animal models, contributing to satiety

—

Body weight impact

Not observed with native GLP-1 — requires analogue formulations

—

04Side Effects & Safety

Parameter

GLP-1 (7-37)

PT-141

Native GLP-1

Well-tolerated in research settings; no prolonged exposure data

—

Hypoglycemia risk

Low — insulin secretion is glucose-dependent

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Analogue side effects

Nausea, vomiting, diarrhea (GLP-1R agonists)

Not applicable to native GLP-1 due to non-therapeutic use.

—

GLP-1 resistance

High glucose-induced PKCβ overexpression may reduce GLP-1 responsiveness in endothelial cellsPujadas 2016

—

Nausea

—

Common (~40%); often transientVYLEESI (bremelanotide injecti 2019

Flushing

—

Common, transient

Injection site reaction

—

Erythema, mild pain

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

Pregnancy / OB

—

Contraindicated

Cardiovascular disease

—

Use caution; transient BP rise

Absolute Contraindications

GLP-1 (7-37)

—

PT-141

·Uncontrolled hypertension
·Known cardiovascular disease (caution)
·Pregnancy

Relative Contraindications

GLP-1 (7-37)

—

PT-141

·Pre-existing hyperpigmentation disorders
·MC4R-pathway-dependent psychiatric conditions

05Administration Protocol

Parameter

GLP-1 (7-37)

PT-141

1. Research use only

Native GLP-1(7-37) is not formulated for therapeutic use. Administered IV or SC in experimental protocols to study GLP-1R pharmacology and as reference standard for analogue development.

Vyleesi: pre-filled auto-injector. Research vial: 2 mL bacteriostatic water per 10 mg → 5 mg/mL.

2. Storage

Lyophilised peptide stored at -20°C or below. Reconstituted solutions should be prepared fresh and used immediately due to rapid degradation.

SQ — abdomen or thigh.

3. Clinical alternatives

For therapeutic GLP-1R activation, use FDA-approved long-acting analogues: semaglutide (once weekly), liraglutide (once daily), dulaglutide (once weekly), or exenatide (twice daily or once weekly).

≥45 min before sexual activity for peak effect. Effect persists ~6–8 h.

4. Storage

—

Vyleesi: room temp ≤30 °C. Research vial: refrigerate after reconstitution.

5. Needle

—

Auto-injector (Vyleesi) or 29–31G, 4–8 mm insulin syringe.