Read This First
This page is not built on clinical evidence. It is built on the approved product's label, the FDA's compounding rules, and the regulatory record of the compound's closest relative. What bremelanotide does in people is covered on the library entry; this page is about the difference between a single-dose autoinjector with a label and a vial of "PT-141" from a vendor that also sells tanning peptides.
Bremelanotide is unusual in this library because an approved product exists, and unusual in a second way: almost nobody buying "PT-141" is the person the product was approved for. Vyleesi is a prefilled autoinjector for premenopausal women with a diagnosed desire disorder.1 The gray market sells lyophilised powder to men, from the same suppliers and often the same product pages as melanotan II.
The Approved Product
What Is It?
Vyleesi: 1.75 mg bremelanotide in 0.3 mL, in a single-dose disposable autoinjector, in cartons of two or four, stored at or below 25°C, protected from light, not frozen. Approved 21 June 2019; held since 2023 by Cosette Pharmaceuticals.1 There is no vial, no reconstitution and no dose adjustment; the device delivers one labelled dose.
What Does "Approved" Guarantee?
Identity, content, sterility, stability through the labelled shelf life, a validated manufacturing process, and a label that says who should not use it and how often it can be used. Those are the things a certificate on a gray-market vial is trying to imitate.
What approval does not guarantee is that the product is being used as approved. The label limits it to premenopausal women with acquired, generalised HSDD, states it "is not indicated for the treatment of HSDD in postmenopausal women or in men," and states it "is not indicated to enhance sexual performance."1 A prescription for a man is off-label, which is lawful; it is also a prescription for a use the trials did not test by this route.
Compounded Bremelanotide
Is It Legal?
Sometimes. Bremelanotide is the active ingredient of an approved drug, so it can be compounded by 503A pharmacies without a bulks-list entry, but not as "essentially a copy" of the commercial product. The FDA's guidance treats a compounded product with the same active ingredient, a similar strength and the same route as a copy unless a prescriber documents a patient-specific difference, and says a lower price is not one.2
For a woman who could use Vyleesi, a compounded 1.75 mg subcutaneous product is a copy. For a man, the position is stranger: no approved product exists for him, so a compounded product is not a copy of one, but the prescriber is prescribing a compounded version of a drug whose label excludes him, for a use the label names as not indicated. That is not a gray area of compounding law. It is off-label prescribing dressed as compounding.
What Should a Compounded Product Come With?
A prescription from a named prescriber, and a stated reason the approved product is not being used
A pharmacy label with the pharmacy's name, licence state, lot number and beyond-use date
A stated strength per millilitre, so that a dose can be drawn without guessing
Blood pressure screening on record, since the approved label contraindicates the drug in uncontrolled hypertension and cardiovascular disease1
Research-Labelled Product
What Is Being Sold?
Lyophilised powder, commonly 10 mg vials, labelled for research use, sold alongside melanotan I and melanotan II by the same vendors. That adjacency is the sourcing fact that matters. Bremelanotide is a metabolite of melanotan II; the two are made by the same chemistry, in the same facilities, and a vendor's melanotan II product is one deamidation away from its PT-141 product.
Melanotan II has its own FDA compounding entry, and it is one of the few that names outcomes: "published case reports discuss serious adverse events including melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome and priapism."3 A vial of PT-141 contaminated with, or substituted by, its parent compound would carry that profile. A purity certificate would not distinguish them unless the mass was reported: they differ by one dalton.
Does "Research Use Only" Change Anything?
No. It is a liability position adopted by the seller, not a regulatory category. The FDA has held in warning letters that the disclaimer does not survive product copy establishing human use.4 For a molecule that is an approved drug, a page disclaiming human use while describing dose timing before sexual activity has supplied the agency's argument.
Purity Testing Versus Identity Testing
| Test | Question it answers | Question it cannot answer |
|---|---|---|
| HPLC purity | What proportion of the sample is one substance | Whether that substance is bremelanotide or melanotan II, which co-elute closely |
| Mass spectrometry identity | Whether the observed mass is 1,025 (bremelanotide) or 1,024 (melanotan II) | Only if the mass is reported to the dalton; "conforms" does not resolve it |
| Endotoxin assay | Whether bacterial cell-wall fragments are present | Identity or content |
| Sterility | Whether viable organisms are present | Anything about the peptide |
For this compound the observed mass on a certificate is the number that answers the question the label is most likely to be wrong about.
Certificates of Analysis
A laboratory report on one batch. Read it for the laboratory's independence from the seller, the lot number and whether it matches the vial, the date, the observed mass, and which tests were run. It cannot establish that the vial in hand came from the batch tested; that rests on a chain of custody the buyer cannot inspect. A certificate is a PDF, and the FDA has documented fabricated labels on gray-market peptide products.5
The Dose Problem
Why Does the Autoinjector Matter?
Because the label's dose limits are the drug's safety case. One dose per 24 hours and no more than eight a month exist because each dose raises blood pressure and lowers heart rate for up to 12 hours, because doses close together have additive effects on blood pressure, and because hyperpigmentation rose with daily dosing.1 The autoinjector makes the labelled dose the only dose available.
A 10 mg vial is roughly six labelled doses in one container, to be reconstituted, drawn and measured by the user. Community protocols for men start at doses near or above the approved one and go up. Every property the approval established about tolerability belongs to 1.75 mg, eight times a month, in women with screened hearts.
Storage and Handling
What the Label Says
Vyleesi is stored at or below 25°C, protected from light, not frozen, as a sealed single-dose device.1 Those figures belong to that formulation in that device. They do not transfer to a reconstituted vial.
Multi-Dose Vials
The FDA's guidance for compounded injectables is to discard a multi-dose vial within 28 days of first use regardless of what remains, and to use a new sterile needle and syringe for every dose.5 For an as-needed drug limited to eight uses a month, a reconstituted vial routinely outlives that window.
Signs to Stop Rather Than Proceed
Headache, flushing or a pounding pulse after a dose, which are the labelled signs of the blood pressure effect, especially in anyone with hypertension or heart disease, for whom the drug is contraindicated1
Any new darkening of skin on the face, gums, breasts or elsewhere, which the label says may not resolve
New moles, or changes in existing ones, which is the melanotan II signal and the reason a mislabelled vial matters3
An erection lasting more than four hours, a documented melanotan II event and a medical emergency
A certificate whose mass does not resolve bremelanotide from melanotan II
Community Language
PT-141
Palatin's development code for bremelanotide. The same molecule as Vyleesi, when it is.
Bremelanotide, Vyleesi
The nonproprietary name and the approved product.
Melanotan II, MT-2
The parent compound: a tanning peptide with a documented melanoma, priapism and encephalopathy signal, sold by the same vendors and differing from bremelanotide by one dalton.3
Essentially a copy
The legal test for whether a compounded version of an approved drug is permitted. Cost is not a qualifying difference.2
Certificate of analysis
A laboratory report on one batch. The approved product does not need one; for a research vial, the mass on it is what matters.
Related ONPEPS Coverage
PT-141 library entry: the trials, the label and the off-label market
Tesamorelin sourcing and quality: the approved product, the copy and the vial
Compounded, gray market and counterfeit semaglutide: what the regulators have documented
Sources
Cosette Pharmaceuticals, Inc. VYLEESI (bremelanotide) injection: prescribing information. Revised March 2024. DailyMed. dailymed.nlm.nih.gov
US Food and Drug Administration. Compounded Drug Products That Are Essentially Copies of a Commercially Available Drug Product Under Section 503A of the Federal Food, Drug, and Cosmetic Act: Guidance for Industry. January 2018. fda.gov
US Food and Drug Administration. Category 2 of the Bulk Substances Nominated Under Sections 503A or 503B of the Federal Food, Drug, and Cosmetic Act. Entry for Melanotan II. Content current as of 22 April 2026. fda.gov
US Food and Drug Administration. Warning Letter: Gram Peptides. MARCS-CMS 721806, 31 March 2026. fda.gov
US Food and Drug Administration. FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. Drug Alerts and Statements. Cited for the agency's general guidance on multi-dose vials and fabricated labels. fda.gov
Not Medical Advice
Bremelanotide is a prescription medicine with cardiovascular contraindications and dose limits set out in its label. If you are using a product obtained outside a pharmacy, the route back to oversight is a clinician who knows what you have taken, and a blood pressure reading is the first thing to bring.
Label and regulatory sources verified 16 September 2026. Compounding enforcement and product availability change frequently. Re-verify before relying on any statement here.