Why is nausea so common with PT-141?
Melanocortin-4 receptor activation affects central nausea pathways; 40% of trial participants reported it, mostly after the first dose, and it tended to lessen with subsequent doses.
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Tier 1 — FDA Approved (HSDD)
PT-141
Central MC3R/MC4R Agonism & Arousal Pathways
Bremelanotide — Melanocortin Receptor Agonist
Last reviewed: August 2026
Research Purposes Only. PT-141 is supplied by Purgo Labs strictly for qualified laboratory research use only. It is not intended for human or veterinary use, nor for diagnostic, therapeutic, or cosmetic application. Statements on this page have not been evaluated by the FDA.
CR
Written By
Compound Review Research Team
Reviewed for Scientific Accuracy By
Megan FleuryPharmD, MBA, RP
Reviewed the scientific, mechanism, and research content on this page. This review does not cover dosing protocols or sourcing/vendor information, which are provided separately for research reference only.
Reviewed: August 2026
All content is reviewed for scientific accuracy against peer-reviewed literature. View our editorial methodology.
So What Does This Actually Mean?
Plain English summary — no PhD required
PT-141 (Bremelanotide) is a synthetic peptide that works through the brain's melanocortin system to influence sexual arousal. Unlike drugs like Viagra or Cialis, which work by increasing blood flow to genital tissue, PT-141 works centrally — in the brain — activating the neural pathways that generate sexual desire itself. It was FDA-approved in 2019 under the brand name Vyleesi® for hypoactive sexual desire disorder (HSDD) in premenopausal women.
What It Does
PT-141 activates melanocortin receptors (primarily MC3R and MC4R) in the hypothalamus and limbic system — brain regions that regulate motivation, reward, and sexual behavior. This central mechanism produces arousal at the neurological level rather than just the vascular level. In the FDA approval trials, Vyleesi® demonstrated statistically significant improvements in sexual desire and reductions in distress related to low desire compared to placebo.
Why It Matters
The distinction between a central (brain-based) and peripheral (blood flow-based) mechanism for sexual function is clinically significant. Many cases of sexual dysfunction, particularly in women, involve desire and arousal at the psychological/neurological level rather than purely vascular issues. PT-141's FDA approval for HSDD validates the melanocortin pathway as a legitimate therapeutic target for sexual health.
The Bottom Line
PT-141 is FDA-approved as Vyleesi® for female sexual desire disorder, giving it one of the strongest clinical validation profiles in this catalog. Its central mechanism — working through the brain rather than blood vessels — distinguishes it from conventional sexual health drugs. The research-grade peptide supplied by Purgo Labs is for laboratory use only.
Overview
What is PT-141?
PT-141, clinically known as bremelanotide, is a synthetic cyclic heptapeptide melanocortin receptor agonist derived from Melanotan II. It is FDA-approved under the brand name Vyleesi® for the treatment of hypoactive sexual desire disorder (HSDD) in premenopausal women, making it one of the few peptides in this catalog with full regulatory approval and extensive human clinical data.
Unlike phosphodiesterase-5 (PDE5) inhibitors such as sildenafil, which act peripherally on vascular smooth muscle, PT-141 acts centrally through melanocortin receptors in the brain — specifically MC3R and MC4R in the hypothalamus and limbic system. This central mechanism of action represents a fundamentally different approach to sexual dysfunction research.
Key Takeaways
- PT-141 (Bremelanotide) is a cyclic heptapeptide melanocortin receptor agonist — the same compound FDA-approved as Vyleesi® (2019) for hypoactive sexual desire disorder (HSDD) in premenopausal women.
- Activates MC3R and MC4R in the central nervous system, particularly in the hypothalamus and limbic system, producing pro-sexual effects through a CNS pathway distinct from PDE5 inhibitors (sildenafil, tadalafil).
- Unlike PDE5 inhibitors which act peripherally on vascular smooth muscle, PT-141 acts centrally — it can produce sexual arousal in the absence of direct genital stimulation, and works in both men and women.
- The FDA approval of bremelanotide (Vyleesi®) provides robust clinical validation: Phase 3 trials showed statistically significant improvements in desire and reductions in distress in women with HSDD.
- Research applications include studying the central melanocortin system's role in sexual motivation, the MC4R pathway in reward and arousal, and potential applications in male sexual dysfunction.
Composition
Molecular Composition
Amino Acid Sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
PT-141 (bremelanotide) has the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, differing from Melanotan II (MT2) by a single modification: the C-terminal amide group of MT2 is replaced by a free carboxylic acid (OH) in PT-141. This modification reduces the compound's melanogenic activity (reducing tanning side effects) while preserving its central melanocortin receptor agonism.
The molecular weight is 1,025.2 Daltons. The cyclic structure, formed by a lactam bridge between aspartate and lysine, confers metabolic stability and enhanced receptor binding affinity.
Mechanism of Action
How Does It Work?
!
PT-141 increases sexual desire by activating melanocortin receptors in the hypothalamus, enhancing dopaminergic signaling in the brain's reward and arousal circuits.
PT-141 exerts its primary effects through agonism at MC3R and MC4R in the central nervous system, particularly in the hypothalamus, limbic system, and spinal cord. MC4R activation in the medial preoptic area (MPOA) of the hypothalamus — a region critical for sexual motivation and behavior — increases dopaminergic neurotransmission in the mesolimbic pathway, enhancing sexual desire and arousal.
Unlike PDE5 inhibitors, which require sexual stimulation to be effective and act primarily on penile/clitoral blood flow, PT-141 modulates the central neural circuits that generate sexual desire. This distinction is clinically significant: PT-141 can increase sexual motivation in the absence of external stimulation, addressing the desire component of sexual dysfunction rather than the performance component.
"Bremelanotide's central mechanism of action, targeting melanocortin receptors in the hypothalamus to modulate sexual desire pathways, represents a paradigm shift in the pharmacological approach to sexual dysfunction." — Diamond et al., Journal of Sexual Medicine, 2006
Signaling Pathways
Key Research Pathways
MC4R / Hypothalamic Sexual Motivation
MC4R activation in the medial preoptic area (MPOA) increases dopaminergic signaling in the mesolimbic pathway, enhancing sexual desire.
MC3R / Limbic System Modulation
MC3R agonism in limbic structures contributes to arousal and emotional components of sexual motivation.
Dopaminergic Mesolimbic Pathway
Central melanocortin activation increases dopamine release in the nucleus accumbens and ventral tegmental area, the reward circuitry of sexual motivation.
Spinal MC4R / Erectile Signaling
MC4R activation in the spinal cord stimulates nitric oxide-mediated pro-erectile signaling, contributing to peripheral arousal responses.
Research Highlights
Key Findings from the Literature
- FDA-approved (Vyleesi®) for hypoactive sexual desire disorder (HSDD) in premenopausal women
- Central mechanism: MC3R/MC4R agonism in hypothalamus — distinct from peripheral PDE5 inhibitors
- Increases dopaminergic neurotransmission in mesolimbic pathway, enhancing sexual desire
- Effective in both male and female sexual dysfunction models (Diamond et al., 2006)
- Cyclic structure derived from MT2 with C-terminal modification reducing melanogenic activity
- Activates MC4R in medial preoptic area (MPOA) — critical region for sexual motivation
Outcome Matrix
Evidence by Claimed Outcome
Each outcome rated by the highest level of evidence available. Tiers follow our 5-tier methodology.
StrongModeratePreliminaryPreclinicalTheoretical
Claimed Outcome
Evidence Tier
Studies
Key Evidence Note
Female sexual dysfunction (HSDD)
Strong
8
FDA-approved (Vyleesi); Phase III trial (n=1,247) confirmed efficacy
Libido enhancement
Strong
6
Primary endpoint in Phase III HSDD trials
Male erectile dysfunction
Moderate
4
Phase II data; not FDA-approved for this indication
Study counts reflect peer-reviewed publications in the evidence database below. "Theoretical" outcomes have mechanistic rationale only. Learn about our evidence tiers →
Evidence Database
Structured Evidence Table
2 cited studies — model, sample size, outcome, and effect size from published literature.
| Study | Model | Sample | Outcome | Effect Size | Level |
|---|---|---|---|---|---|
Diamond LE, et al. (2004) Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic prope… PubMed | Human — Phase II RCT | n=20 | Significant increase in erectile response vs. placebo; centrally mediated | Significant improvement in erectile function scores (p<0.05) | Phase II |
Clayton AH, et al. (2016) Bremelanotide for Female Sexual Dysfunctions in Premenopausal Women PubMed | Human — Phase III RCT (HSDD) | n=1267 | Significant improvement in satisfying sexual events and desire in women with HSDD | SSE increase: +0.7 vs. +0.2 placebo (p<0.001); FDA approved 2019 | Phase III |
Diamond LE, et al. (2004)
Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141
Model
Human — Phase II RCT
Sample
n=20
Effect Size
Significant improvement in erectile function scores (p<0.05)
Clayton AH, et al. (2016)
Bremelanotide for Female Sexual Dysfunctions in Premenopausal Women
Model
Human — Phase III RCT (HSDD)
Sample
n=1267
Effect Size
SSE increase: +0.7 vs. +0.2 placebo (p<0.001); FDA approved 2019
Evidence levels:RCTPhase IIIPhase IIObservationalAnimalIn Vitro
Evidence table is for educational reference only. Most peptide research is preclinical. Human RCT data is limited for most compounds. All compounds are for research purposes only — not for human use.
Researcher Notes
Important Research Context
PT-141 (bremelanotide) has completed Phase III clinical trials and received FDA approval in 2019. The RECONNECT trials demonstrated statistically significant improvements in satisfying sexual events and sexual desire scores in premenopausal women with HSDD. The approved clinical formulation is a 1.75mg subcutaneous auto-injector. Researchers should note that nausea is the most common adverse effect, occurring in approximately 40% of subjects in clinical trials.
Research References
Peer-reviewed literature supporting the research profile of PT-141
The following peer-reviewed studies form the primary evidence base for PT-141's research profile. All references are sourced from PubMed, NCBI, and peer-reviewed scientific journals. Published research is available through PubMed, NCBI, and peer-reviewed biomedical journals.
- 1.
Diamond LE, et al. A double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141, a melanocortin receptor agonist, in healthy males and patients with mild-to-moderate erectile dysfunction. International Journal of Impotence Research. 2004.PMID: 14963471
PT-141 demonstrated pro-erectile effects via central melanocortin receptor activation in controlled clinical evaluation.
- 2.
Safarinejad MR, Hosseini SY. Salvage of sildenafil failures with bremelanotide: a randomized, double-blind, placebo controlled study. Journal of Urology. 2008.PMID: 18206919
PT-141 (bremelanotide) improved sexual arousal and desire in women with hypoactive sexual desire disorder.
- 3.
Clayton AH, et al. Bremelanotide for Female Sexual Dysfunctions in Premenopausal Women. Women's Health (London). 2016.PMID: 27181790
Phase III data supporting bremelanotide (PT-141) approval for HSDD in premenopausal women.
Research Databases
PT-141
Sexual Health Research
From $29.99
Purgo Labs list price, read 12 Sep 2026 · per-lot COA on the vendor page
1 vial (10mg)
List price · read 12 Sep 2026
$29.99
10mg $29.99 → $23.99 with code HEALTH (20% off; price read 1 Nov 2026)
Where to buy PT-141
17 partners · prices read from product pages, latest 1 Nov · ranked by rubric, then price
- 1 certificate verified at the lab10mg$29.99→ $23.99
- 2 certificates verified at the lab10mg$30.00→ $24.00
- 1 certificate verified at the lab10mg$34.99$20.99→ $18.89
Every order also needs bacteriostatic water — add it to the same cart.All PT-141 vendors, partners and not
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Sourced from Purgo Labs
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🏭cGMP Made
Technical Specifications
- Peptide Class
- Cyclic heptapeptide melanocortin agonist
- Molecular Weight
- 1,025.2 Da
- FDA Approval
- Vyleesi® — HSDD in premenopausal women
- Receptor Targets
- MC3R, MC4R (central nervous system)
- Mechanism Type
- Central (hypothalamic) — vs. peripheral PDE5 inhibitors
- Available Sizes
- 10mg vials
- Form
- Lyophilized powder
- Purity
- ≥99% (third-party tested)
Legal Status
FDA-Approved (Vyleesi)
View full legal status guide →
Source PT-141 at Purgo Labs
10mg $29.99 list · $23.99 with code HEALTH · lab-verifiable COA per lot
Vendor Scoreboard — top 3 by verified evidenceVerified 1 November 2026
Related Research
Other Compounds in This Guide
Safety
PT-141 side effects
Approved-drug dataApproved drug (Vyleesi) — figures are from its label and the RECONNECT trials
Bremelanotide is approved for hypoactive sexual desire disorder in premenopausal women, so its adverse effects are documented from controlled trials: nausea is by far the most common, followed by flushing, injection-site reactions and headache. It also causes a transient rise in blood pressure, which is why uncontrolled hypertension is a contraindication.
Research-use information only. Research-grade PT-141 is not an approved medicine; where trial or label figures appear below they belong to the pharmaceutical product studied, not to any research vial. This section does not give dosing or medical advice.
What is reported
Every rate carries its source. Where no source exists, no rate is printed.
| Effect | Rate (sourced) | Detail | Source |
|---|---|---|---|
| Nausea | 40% vs 1.3% placebo | Most in the first dose; 13% needed an antiemetic in trials. | Vyleesi label (RECONNECT) |
| Flushing | 20.3% vs 0.3% | — | Vyleesi label |
| Injection-site reactions | 13.2% vs 8.9% | — | Vyleesi label |
| Headache | 11.3% vs 1.9% | — | Vyleesi label |
| Transient blood-pressure increase | not quantified | About 6 mmHg systolic / 3 mmHg diastolic, peaking 2–4 h after dosing and resolving by 12 h. | Vyleesi label |
| Focal hyperpigmentation | not quantified | Reported with more than 8 doses per month; more common in darker skin. | Vyleesi label |
What is not known
- •Use in men (the approval is in women; early studies in men were discontinued).
- •Research-grade identity and dose.
Mechanism-based cautions
- •Contraindicated in uncontrolled hypertension or known cardiovascular disease.
- •Slows gastric emptying — can reduce absorption of oral medicines taken at the same time.
Regulatory status: FDA-approved as Vyleesi (2019). Research-grade PT-141 is not approved for any use.
Side-effect references
- Kingsberg SA, et al. Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials (RECONNECT). Obstetrics & Gynecology, 2019.
What is actually in a research vial
Everything above describes PT-141 the molecule. The risk specific to a research vial is different: it may not contain PT-141 at the labelled amount, and it may contain what the synthesis left behind. Identity (mass spectrometry), purity (HPLC), measured net content and an endotoxin result are the four lines on a certificate that bear on adverse effects, and only a certificate you can check at the laboratory tells you any of them. This is what we have verified for PT-141 so far.
Who sells PT-141, and what they document
30 of the 105 vendors on our scoreboard list PT-141 with a price we read on the product page (23 Sep 2026–1 Nov 2026). Of those, 29 name their testing laboratory, 24 publish certificates that resolve on the lab's own site, and 27 publish measured milligrams against the label. The full ranking, with every dated price, is on Best PT-141 Vendors.
| Vendor | Rubric | Lab named | Price read |
|---|---|---|---|
| MyPurePeptidepartner | 10/10 | Janoshik Analytical | $30.00 · 10mg · 10 Oct 2026 |
| Oneday Compoundspartner | 10/10 | ILS Laboratories (San Diego, CA) | $20.99 · 10mg · 29 Oct 2026 |
| Panda Peptides | 10/10 | Janoshik Analytical · ILS Labs (per batch) | $28.00 · 10mg · 25 Oct 2026 |
| Peptide Giantspartner | 10/10 | Janoshik Analytical · Vanguard Laboratory | $32.00 · 10mg · 1 Nov 2026 |
| Purgo Labspartner | 10/10 | SteriGenix · Freedom Diagnostics | $29.99 · 10mg · 1 Nov 2026 |
Top 5 by rubric score; 25 more on the ranking page.
PT-141 certificates we have opened
None yet for PT-141 specifically. The COA library holds the certificates we have read for each vendor on other compounds, which is the next best signal of how that vendor documents a lot.
Side-effect questions
Side-effect section last reviewed 2026-09-12. Moved from the standalone side-effects page on 10 October 2026; text unchanged.
Regulatory
Is PT-141 legal?
FDA-approved (prescription only)PT-141 (bremelanotide) is FDA-approved as Vyleesi for hypoactive sexual desire disorder in premenopausal women. As a research chemical, it is available for laboratory research. It is not a controlled substance but requires a prescription for clinical human use.
US Status
Research Chemical
Legal to purchase for research
DEA Schedule
Not Scheduled
Not a controlled substance
FDA Status
Not Approved
FDA-approved as Vyleesi (prescription required for human use)
Status by country
| Jurisdiction | Status as stated |
|---|---|
| United States | FDA-approved as Vyleesi (bremelanotide) for clinical use. Not a controlled substance. Available as a research chemical for laboratory research purposes. |
| Canada | Not approved by Health Canada for clinical use. Available for research purposes. |
| United Kingdom | Not licensed by the MHRA for clinical use. Available for research purposes. |
| Australia | Not approved by the TGA for clinical use. Available for research purposes. |
| European Union | Not approved by the EMA as a medicinal product. Available for research purposes in most member states. |
Statements above are as our legal-status page for PT-141 stated them in 2025; they were moved here on 10 October 2026 and were not re-verified in the move. Regulations change. This is general information, not legal advice; check the current position with your own jurisdiction's regulator before relying on it.
Legal questions
Is PT-141 a controlled substance?
No. PT-141 (bremelanotide) is not listed as a controlled substance under the DEA Controlled Substances Act.
Is PT-141 the same as Vyleesi?
Yes. PT-141 is the research name for bremelanotide, which is marketed as Vyleesi by Palatin Technologies. The FDA-approved Vyleesi requires a prescription.
Can I buy PT-141 legally without a prescription?
Research-grade PT-141 is available as a research chemical without a prescription for legitimate laboratory research purposes. Clinical use requires a prescription.
Is PT-141 banned in sports?
PT-141 is not specifically listed on the WADA prohibited list as of 2025. However, athletes should verify current guidelines before use.
Is PT-141 legal in the UK?
PT-141 is not licensed as a medicine in the UK by the MHRA. It is available for research purposes but is not approved for clinical human use.
Everything we publish on PT-141
More on PT-141: comparisons, interactions, where to buy
Supporting Research
Strong Human EvidenceStrong Human Evidence (FDA-approved Vyleesi®; Phase 3 RCT)
Evidence note: FDA approval is specifically for HSDD in premenopausal women. Use in men or for other sexual dysfunction indications is not supported by the pivotal trial data. Research-grade PT-141 from Purgo Labs is for laboratory use only and differs from the clinical Vyleesi® formulation.
PT-141 (bremelanotide) is FDA-approved as Vyleesi® (2019) for hypoactive sexual desire disorder (HSDD) in premenopausal women. This is one of the strongest clinical validation profiles in this catalog. The approval is specifically for HSDD in premenopausal women; off-label use in men or for other indications is not supported by the pivotal trial data.
References
- Clayton AH, et al.HUMAN RCT, Phase 3Bremelanotide for Female Sexual Dysfunctions in Premenopausal Women. Women's Health (London). 2016. PubMedPhase III data supporting bremelanotide (PT-141) approval for HSDD in premenopausal women.
- Kingsberg SA, et al.HUMAN RCT, Phase 3Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstetrics & Gynecology. 2019. PubMedTwo Phase 3 RCTs confirmed significant improvement in satisfying sexual events and desire scores vs placebo.
Research Databases
PubMedClinicalTrials.gov
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