PT-141, known by its generic name bremelanotide, is a synthetic cyclic peptide that activates melanocortin receptors in the brain. It was developed from Melanotan II and is FDA-approved under the brand name Vyleesi, while the material sold by research suppliers is intended for laboratory study of melanocortin signaling. This guide covers what PT-141 is, how it works, its research areas and lab handling.
What is PT-141 (bremelanotide)?
PT-141 is a seven-residue cyclic peptide in the melanocortin family, the group of peptides that includes alpha-melanocyte-stimulating hormone (alpha-MSH). It was derived from Melanotan II, a synthetic alpha-MSH analog first developed in tanning research. Researchers noticed effects of Melanotan II on sexual behavior and arousal pathways, and PT-141 emerged from work to develop a compound for that line of investigation.
Structurally, PT-141 is very close to Melanotan II. Both have a lactam bridge that holds the peptide in a ring, which increases stability and receptor affinity. The main difference is at the C-terminus: PT-141 carries a free carboxylic acid where Melanotan II is amidated. That small change is associated with a different research profile, with less emphasis on pigmentation.
Bremelanotide is FDA-approved as Vyleesi for hypoactive sexual desire disorder in premenopausal women. PT-141 supplied by PRIME is research-grade material for laboratory use only. It is not the approved drug product and is not for human consumption.
How PT-141 works: mechanism studied in research
The melanocortin system includes five receptors, MC1R through MC5R, which take part in pigmentation, inflammation, energy balance and sexual behavior. PT-141 is a non-selective agonist with activity at several of them, and research attention has focused on MC3R and MC4R in the central nervous system.
Key points from research:
- Central action: unlike PDE5 inhibitors, which act on blood flow, PT-141 is studied as a compound that acts in the brain, particularly in hypothalamic regions involved in motivation and sexual behavior.
- MC4R signaling: activation of MC4R in these regions is thought to influence dopamine release in reward and motivation pathways.
- MC1R activity: PT-141 also acts at MC1R, the receptor that drives pigmentation, although to a lesser extent than Melanotan II in comparable research.
- Cardiovascular and appetite effects: because MC4R also plays a part in blood pressure regulation and energy balance, these effects are tracked in melanocortin research.
This central mechanism makes PT-141 a useful tool for studying how melanocortin signaling connects to motivated behavior.
Why PT-141 matters in melanocortin research
The melanocortin system is unusual in that a single family of receptors influences processes as different as skin pigmentation, appetite, inflammation and sexual behavior. Tool compounds with distinct receptor profiles let researchers pull these functions apart. PT-141 is useful here because it is closely related to Melanotan II but has a research profile weighted toward central effects rather than pigmentation, so comparing the two can show which outcomes depend on small structural differences.
PT-141 is also one of the few melanocortin agonists to reach regulatory approval, which means a large body of pharmacology on it exists in the public record. For laboratory work, that background makes it a well-characterized reference compound when studying MC4R-driven signaling or when testing newer, more selective melanocortin ligands against an established benchmark.
Areas of research
PT-141 has been studied in animal models and in clinical trials that led to its approval. Research areas include:
- Melanocortin receptor pharmacology: receptor selectivity and signaling across MC1R to MC5R
- Neuroscience of sexual behavior: hypothalamic and dopaminergic pathways in animal models
- Clinical research in sexual function: studies in women with hypoactive sexual desire disorder and earlier investigation in erectile dysfunction
- Comparative melanocortin research: how PT-141 differs from Melanotan II and alpha-MSH in activity and effects
- Cardiovascular monitoring: blood pressure responses to MC4R activation
PT-141 key facts table
| Property | Detail |
|---|---|
| Compound class | Synthetic cyclic melanocortin peptide |
| Other names | Bremelanotide; approved product marketed as Vyleesi |
| Structure | Cyclic heptapeptide with a lactam bridge; C-terminal free acid |
| Targets | Melanocortin receptors, with research focus on MC3R and MC4R |
| Form supplied | Lyophilized powder in a sealed vial |
| Regulatory status | Bremelanotide is FDA-approved (Vyleesi); PRIME material is for research use only |
| Storage | Lyophilized: cold, dry, dark. Reconstituted: refrigerated |
Handling and storage in the lab
PT-141 is supplied as a lyophilized powder. Its cyclic structure makes it more stable than many linear peptides, but it still needs careful handling. General lab handling points:
- Equilibrate: let the vial warm to room temperature before opening to limit condensation.
- Reconstitution: for lab use, reconstitute with bacteriostatic water or an assay-appropriate buffer, adding it slowly down the vial wall and swirling gently.
- Dry storage: keep sealed vials cold, dry and away from light, with a freezer preferred for long-term storage.
- Solution storage: refrigerate reconstituted material, protect it from light and aliquot to avoid repeated freeze-thaw cycles.
- Avoid mix-ups: PT-141 and Melanotan II look identical as powders. Label clearly and store them apart.
Quality and lab results
Since PT-141 and Melanotan II differ only at the C-terminus, identity testing is the only reliable way to confirm which compound is in the vial. Every PRIME batch is tested, and the certificate of analysis for each lot is published. Review current reports on the lab results (COA) page before starting an experiment.
Research material is available as PT-141 (bremelanotide).
Related research
- PT-141 vs Melanotan II: how the two closely related melanocortin peptides differ
- Melanotan II research guide: the parent compound studied in pigmentation research
- KPV research guide: an alpha-MSH derived tripeptide studied in inflammation research
PT-141 FAQ
What is PT-141?
PT-141 is bremelanotide, a synthetic cyclic peptide that activates melanocortin receptors, especially MC3R and MC4R in the brain. It is studied in research on melanocortin signaling and the neuroscience of sexual behavior.
Is PT-141 FDA approved?
Bremelanotide is FDA-approved as Vyleesi for hypoactive sexual desire disorder in premenopausal women. PT-141 sold by PRIME is research-grade material for laboratory use only and is not the approved drug product.
What is the difference between PT-141 and Melanotan II?
PT-141 was derived from Melanotan II and differs mainly at the C-terminus, where it has a free acid instead of an amide. In research, Melanotan II is associated more with pigmentation through MC1R, while PT-141 is studied mainly for central MC4R effects.
How does PT-141 differ from PDE5 inhibitors in research?
PDE5 inhibitors act on blood vessels by affecting nitric oxide signaling. PT-141 is studied as a centrally acting compound that works through melanocortin receptors in the brain, a separate mechanism.
How should PT-141 be stored?
Store lyophilized vials cold, dry and protected from light. After reconstitution for lab use, refrigerate the solution, keep it out of light and avoid repeated freezing and thawing.
For laboratory research use only. Not for human consumption. Not a drug, food or cosmetic.