Are Peptides Legal in Canada? What to Know in 2026
Are peptides legal in Canada? Learn how Health Canada regulates peptides as drugs, what research use labels mean, and how WADA rules…
Research guide
September 16, 2026
What is PT-141? It is the development code for bremelanotide, a synthetic cyclic peptide of seven amino acids that activates melanocortin receptors. It is closely related to melanotan II, and in 2019 the US Food and Drug Administration (FDA) approved it as Vyleesi, a prescription medicine for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women.
This guide explains the molecule, how it acts on receptors in the central nervous system, and what the Vyleesi prescribing information reports about how long bremelanotide stays in circulation. Flux Peptides supplies PT-141 for laboratory research: it is not Vyleesi, and it is not for human use.
PT-141 is the code name Palatin Technologies used during development, and bremelanotide is the generic name of the same molecule. The Vyleesi label describes it as a synthetic, cyclic heptapeptide with an acetylated amino terminus and a free acid at the carboxyl terminus: Ac-Nle-cyclo-(Asp-His-D-Phe-Arg-Trp-Lys-OH), with a molecular weight of 1025.2 as the free base.
Its closest relative is melanotan II (MT-II), a cyclic analogue of alpha-melanocyte-stimulating hormone (alpha-MSH) that University of Arizona researchers evaluated as a tanning agent in the 1990s. MT-II has the same seven-residue sequence but ends in an amide rather than a free acid. A 2007 review describes PT-141 as a deaminated derivative and likely metabolite of MT-II.
That shared structure is why the two compounds are often studied side by side, and Flux also supplies Melanotan 2 research peptide for comparative melanocortin work in the laboratory.
Bremelanotide acts on the melanocortin system, a family of five receptors (MC1R to MC5R) that respond to hormones such as alpha-MSH. According to its label, it activates several subtypes nonselectively, with an order of potency of MC1R, MC4R, MC3R, MC5R and MC2R, and binding at MC1R and MC4R is the most relevant at therapeutic exposure.
Neurons expressing MC4R are found in many areas of the central nervous system, and early rat studies showed that PT-141 increased c-Fos, a marker of neuronal activation, in the hypothalamus. MC1R is expressed on melanocytes, which explains why pigmentation appears among the label’s warnings. The label is also candid about the limits of current knowledge: it states that the mechanism by which Vyleesi works in HSDD is unknown.
This central route is what separates bremelanotide from PDE5 inhibitors such as sildenafil, which act peripherally by preventing the breakdown of cGMP in smooth muscle within vascular tissue. Melanocortin agonists were investigated as a centrally mediated alternative.
The FDA approved bremelanotide as Vyleesi on June 21, 2019, under NDA 210557. It is indicated for premenopausal women with acquired, generalized HSDD that causes marked distress or interpersonal difficulty and is not due to a co-existing medical or psychiatric condition, relationship problems, or the effects of a medication or drug substance. The label states that it is not indicated for postmenopausal women or men.
Approval followed two identical 24-week, randomized, double-blind, placebo-controlled phase 3 trials, known as RECONNECT, which randomized 1,267 premenopausal women. Palatin Technologies developed the drug and later licensed North American rights to AMAG Pharmaceuticals; the current US label lists Cosette Pharmaceuticals.
On pharmacokinetics, the label reports a median time to peak plasma concentration of about 1.0 hour and a mean terminal half-life of about 2.7 hours. Vyleesi is prescribed by clinicians. Our PT-141 10mg research vials contain research-grade material that is not that medicine and is not for human use.
Questions about how long PT-141 lasts can only be answered with published pharmacokinetics. The values below come from the Vyleesi prescribing information for the approved medicine.
| Parameter | Value reported in the Vyleesi label |
|---|---|
| Median time to peak plasma concentration | About 1.0 hour (range 0.5 to 1.0 hours) |
| Mean terminal half-life | About 2.7 hours (range 1.9 to 4.0 hours) |
| Binding to human serum protein | 21% |
| Mean apparent clearance | 6.5 L per hour (SD 1.0) |
| Metabolism | Multiple hydrolyses of the amide bonds in the cyclic peptide |
| Excretion in a radiolabel study | 64.8% of radioactivity in urine, 22.8% in feces |
Half-life describes how quickly plasma concentrations fall, not how long any effect persists, and the label states that the duration of efficacy is unknown. These figures describe the approved medicine and should not be applied to research material or to any individual; questions about a person’s health belong with a qualified healthcare professional.
Published research on bremelanotide falls into three tiers of evidence:
None of this establishes anything about research-grade PT-141 or about any individual.
Vyleesi is approved in the United States. When we checked Health Canada’s Drug Product Database in September 2026, it contained no product listing for bremelanotide. Flux’s PT-141 is not authorized by Health Canada for human or veterinary use; it is sold as a laboratory reagent, and we do not publish dosing information of any kind. Our guide to whether peptides are legal in Canada covers the wider framework.
Every batch is assayed by HPLC against a minimum 99.0% purity specification, and every order carries a batch identifier. Lyophilized stock is sealed and held at minus 20 degrees Celsius; see how to store peptides for handling after delivery. For a very different peptide derived from the same parent hormone, read what KPV peptide is.
PT-141 is bremelanotide, a synthetic cyclic heptapeptide that acts as a melanocortin receptor agonist. It is an analogue of the hormone alpha-MSH and a close structural relative of melanotan II. As an approved drug it is marketed as Vyleesi in the United States; as a research chemical it is supplied as a lyophilized powder for laboratory use only.
Only published pharmacokinetics can answer this. The Vyleesi label reports a median time to peak plasma concentration of about 1 hour and a mean terminal half-life of about 2.7 hours (range 1.9 to 4.0 hours). The peptide is broken down by hydrolysis and excreted mainly in urine, and the label states that the duration of efficacy is unknown.
They share the same active molecule but are not the same product. Vyleesi is an FDA-approved medicine manufactured to a regulated specification and prescribed by clinicians. Research-grade PT-141 is a lyophilized laboratory reagent; it is not Vyleesi, it is not authorized by Health Canada for human or veterinary use, and it must not be used in people.
No, although they are closely related. Both are cyclic seven-residue analogues of alpha-MSH with the same sequence, but melanotan II ends in an amide and bremelanotide in a free acid. Melanotan II was evaluated as a tanning agent in the 1990s, while bremelanotide was developed by Palatin Technologies and went on to FDA approval as Vyleesi.
Flux Peptides supplies PT-141 strictly for laboratory research. It is not approved by Health Canada for human or veterinary use, and nothing in this article is medical advice.
