PT-141
Melanocortin agonist. Libido research, central pathway.
- Boosts libido and arousal by acting on the brain.
- Works differently than blood-flow-based options like sildenafil.
- Effective for both men and women.
Cyclic 7-amino-acid analog of α-MSH. Acts on melanocortin receptors in the CNS — the desire pathway rather than the vascular pathway.
PT-141 is FDA-approved for HSDD as Vyleesi. Onset 30–90 minutes; works centrally rather than via PDE5 inhibition.
- 10.5–2 mg subcutaneous, 45–60 min before activity.
- 2On-demand only — maximum 2 doses per week.
- Reconstitution
- 2 mL bacteriostatic water into a 10 mg vial → 5 mg/mL (each 0.2–0.4 mL = 1–2 mg).
- Typical research dose
- Reference 1–2 mg as-needed, 45–60 min pre-event.
- Frequency
- On-demand only — not a daily peptide.
- Vial duration
- A 10 mg vial covers ~5 doses at 2 mg and ~10 doses at 1 mg. On-demand use almost always finishes well inside the 30-day reconstituted-use window.
- Storage
- Refrigerate 2–8 °C; use within 30 days reconstituted.
Understanding PT-141
Boosts desire from the brain, not the bloodstream
Written for people new to peptides. Clear language, careful claims, no dosing instructions.
+What is PT-141?
PT-141, also known as Bremelanotide, is a synthetic analogue of alpha-MSH that activates the melanocortin system in the brain. Unlike PDE5 inhibitors, it works centrally rather than vascularly.
It is approved in the US for hypoactive sexual desire disorder and is the most clinically validated libido peptide on the market.
+How PT-141 was discovered
PT-141 was developed by Palatin Technologies in the 2000s as a derivative of Melanotan II. It received FDA approval in 2019 as Vyleesi for hypoactive sexual desire disorder in premenopausal women — making it one of the few peptides in the catalog with a formal regulatory approval for libido.
Its central (brain) mechanism is what made it interesting: unlike PDE5 inhibitors (sildenafil, tadalafil) which act on blood vessels, PT-141 works upstream on desire itself.
+How PT-141 works in the body
- PT-141 acts on melanocortin receptors (mainly MC4R) in the central nervous system, which are involved in sexual arousal pathways.
- Because the effect is upstream of vascular response, it influences desire and arousal at the neural level for both sexes — which is why research interest extends beyond the female-libido indication it is approved for.
- MC4R also has roles in appetite and energy expenditure, which is part of why mild appetite changes are sometimes noted alongside the primary effect.
+Benefits
- Boosts libido and arousal by acting on the brain.
- Works differently than blood-flow-based options like sildenafil.
- Effective for both men and women.
+Research highlights
PT-141 has a clinical evidence base in female sexual dysfunction (the basis of its FDA approval) and ongoing research interest in male applications and PDE5-inhibitor non-responders.
Main research areas: melanocortin biology, female hypoactive sexual desire disorder, male erectile dysfunction (especially non-vascular cases), and the broader role of MC4R in motivation.
+What researchers commonly report
Increased desire and arousal within hours of administration is the most common report. Flushing, mild nausea or yawning early in a protocol are also widely noted and typically settle with lower dose / slower titration.
+Why researchers find PT-141 interesting
PT-141 is interesting because it is one of the only approved drugs that acts on sexual desire itself rather than the downstream plumbing — a mechanism that didn't really exist in the toolkit before melanocortin research matured.
+Quality markers we look for
- HPLC purity reviewed with a target of ≥99%
- Mass spectrometry identity confirmation
- LAL endotoxin screening on applicable batches
- Lyophilized (freeze-dried) format for stability
- Careful storage and handling — keep cold, reconstitute with sterile water
+Often paired with
The data your lab notebook needs.
Pulled from the verification packet included with each shipment. Cross-check the batch ID on your vial against the COA.
- Molecular Weight
- 1025.18 g/mol
- Sequence Length
- Cyclic 7 amino acids
- CAS Number
- 189691-06-3
- Synonyms
- Bremelanotide, Vyleesi
- Purity
- 99%+
- Source
- Synthetic
- Storage
- Lyophilized: 2–8 °C. Reconstituted: 2–8 °C, use within 30 days.
- Reconstitution
- Add 2 mL bacteriostatic water. Each 0.1 mL = 500 mcg.
- Half-life
- ~2 hours