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.
Approved-drug data
PT-141 Side Effects
Approved 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 page 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.
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
8 of the 77 vendors on our scoreboard list PT-141 with a price we read on the product page (23 Sept 2026–2 Oct 2026). Of those, 8 name their testing laboratory, 6 publish certificates that resolve on the lab's own site, and 7 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 |
|---|---|---|---|
| Peptide Giantspartner | 10/10 | Janoshik Analytical · Vanguard Laboratory | $32.00 · 10mg · 23 Sept 2026 |
| Purgo Labspartner | 10/10 | SteriGenix · Freedom Diagnostics | $29.99 · 10mg · 2 Oct 2026 |
| Everest Peptides | 8/10 | Freedom Diagnostics | $33.74 · 10mg · 23 Sept 2026 |
| PS Peptidespartner | 8/10 | North American Diagnostics | $44.99 · 10mg · 23 Sept 2026 |
| Modern Aminospartner | 7/10 | Freedom Diagnostics (on certificate) · Kovera · Vanguard · Chromate · TrustPointe (claimed) | $41.00 · 10mg · 23 Sept 2026 |
Top 5 by rubric score; 3 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.