Name: PT-141
Brand: PeptidesDirect
SKU: PD-PT141-10MG
Price: 33.99 EUR
Availability: InStock

Question 1

What is PT-141?

Accepted Answer

PT-141, also called bremelanotide, is a synthetic cyclic peptide of seven amino acids. It is a melanocortin receptor agonist, active at several melanocortin receptor subtypes with research focus on MC3R and MC4R, and it is chemically the active metabolite of Melanotan-II, sharing the same seven residues but with a free acid where Melanotan-II carries a C-terminal amide. Unusually for a research peptide, it has been through full randomised, placebo-controlled human clinical trials. We supply it as a lyophilized powder for laboratory research only, not for human or animal use.

Question 2

How does PT-141 differ from Melanotan-2?

Accepted Answer

They are closely related but distinct molecules. Melanotan-II is a broad melanocortin agonist with strong MC1R activity, the receptor that drives pigmentation. Bremelanotide differs at the C-terminus and shows comparatively less pigmentation-driving activity, though not none: focal hyperpigmentation has been reported in the clinical programme after repeated daily dosing above the approved regimen (PMID 35147466). Because of this and other differences, the two are studied for different endpoints, and results from one should not be transferred to the other.

Question 3

What receptors does PT-141 act on?

Accepted Answer

It is active at melanocortin receptors as a group rather than at one single target: published binding and functional assays profile it across the full family, MC1R through MC5R, alongside its parent compound Melanotan-II. Research attention concentrates on MC3R and MC4R because of their link to the sexual-function and feeding circuits studied for this peptide. In the published in-vitro receptor profile, MC2R, the ACTH receptor that sits upstream of adrenal steroid production, is the subtype activated least potently of the five, which is why it does not feature in discussions of bremelanotide's research relevance.

Question 4

Does PT-141 use a PDE5 or vascular mechanism, or a proposed central pathway?

Accepted Answer

It is not a PDE5 or vascular mechanism. Research compounds targeting PDE5 act on vascular smooth muscle and change blood flow, while preclinical work on bremelanotide implicates melanocortin, MC4R-linked neural pathways in the hypothalamus (PMID 20190196). That said, the mechanism behind the effects observed in human clinical trials is not established; the central pathway is the leading hypothesis from preclinical research, not a proven human mechanism. Direct evidence such as human brain imaging or receptor-occupancy data is not part of the published record reviewed here, so the central mechanism remains an inference from animal data rather than a demonstrated fact in people.

Question 5

Is PT-141 an approved drug?

Accepted Answer

Bremelanotide holds a marketing authorisation in the United States covering a single indication, acquired generalised hypoactive sexual desire disorder in premenopausal women, based on the pivotal phase 3 trial programme (PMID 31599840). There is no EU marketing authorisation, and outside that specific licensed US indication bremelanotide is not an approved medicine anywhere, including within the EU. The material we supply is a research chemical intended strictly for laboratory use, not a medicine, and it is not supplied, labelled or intended for human or animal use.

Question 6

Is PT-141 legal to buy in the EU?

Accepted Answer

There is no single EU-wide answer. Bremelanotide has no EU marketing authorisation, so it may not be sold or used as a medicine anywhere in the EU. We supply and label it strictly as laboratory research material, not for human or animal use. National rules on the sale, possession and import of unlicensed research peptides differ from country to country and can change, so it is the buyer's responsibility to check the current rules in their own country before ordering, rather than treating this page as legal advice.

Question 7

What dosages appear in the published research?

Accepted Answer

These figures come from clinical trials, not from a protocol for use of this research material. In the pivotal RECONNECT phase 3 trials, participants self-administered bremelanotide 1.75 mg subcutaneously on an as-needed basis over 24 weeks of treatment (PMID 31599840). An earlier dose-finding trial tested 0.75, 1.25 and 1.75 mg subcutaneously, also self-administered as desired, over 12 weeks (PMID 27181790). Still earlier work in men used single subcutaneous doses from 0.3 mg up to 10 mg, with a significant erectile response above roughly 1 mg (PMID 14999221). All of these were clinical trial regimens run under medical supervision as part of drug development, not an approved or public protocol, and this research material is not for human use.

Question 8

What side effects are reported in the literature?

Accepted Answer

In the integrated double-blind portion of the phase 3 programme (1247 participants), the most common adverse events were nausea (40.0% versus 1.3% on placebo), flushing (20.3% versus 1.3%), headache (11.3% versus 1.9%) and injection site reactions (5.4% versus 0.5%); nausea was the leading reason participants discontinued (PMID 35147466). Transient increases in blood pressure have also been documented, which is part of why the approved US product carries restrictions against use in uncontrolled hypertension and known cardiovascular disease. Focal hyperpigmentation was rare at the approved dosing regimen but appeared in more than a third of subjects after up to 16 consecutive daily doses (PMID 35147466). These are findings from human clinical trials of an approved medicine, reported here for completeness of the research record; this research material is not for human use.

Question 9

How is PT-141 reconstituted?

Accepted Answer

Published protocols use bacteriostatic or sterile water for injection, not tap or plain drinking water. Add the water slowly down the inner wall of the vial rather than directly onto the lyophilized cake, then swirl gently; avoid shaking, since vigorous agitation can denature the peptide's folded ring structure and reduce activity. The volume added determines the resulting concentration, so it should be chosen to suit the specific study protocol in use. Reconstitution technique, water quality and subsequent handling are the researcher's responsibility.

Question 10

How should PT-141 be stored?

Accepted Answer

Sealed vials: 2 to 8 degrees C, protected from light, away from repeated freeze-thaw cycles. Short ambient-temperature excursions during transit are expected and do not on their own indicate a problem; the range above describes the recommended condition once the vial is in hand. After reconstitution: 2 to 8 degrees C, used within about four weeks. Lyophilized peptide is considerably more stable than peptide in solution, which is why the reconstituted window is much shorter than the sealed shelf life.

Question 11

What purity is the material?

Accepted Answer

Our specification is a content of at least 99% by HPLC, with identity confirmed by mass spectrometry. The current batch is documented in Janoshik task 99774 (QSC batch "Purple"), which measured 99.908% purity and 11.67 mg of content per vial. That content figure, alongside the purity percentage, is what lets a researcher calculate the actual peptide mass in a given reconstituted volume, rather than assuming the whole vial weight is pure peptide. The report itself was commissioned by our supplier, not by us, and we publish it in full on the product page and on our lab-reports page so the figure can be checked against the source rather than taken on trust.

Question 12

Do you provide a CoA?

Accepted Answer

Yes. Each batch has its own certificate of analysis covering identity and purity, produced by Janoshik, an independent third-party analytical laboratory. The testing is commissioned by our supplier rather than by us: our supplier sends the batch for testing, and Janoshik reports the result directly. We publish the full report and its task number, for example task 99774 for the current batch, so the certificate can be verified directly with the lab rather than taken on our word; the task number can also be looked up on Janoshik's own verification page, independent of anything we say about it here.

Question 13

Why does the page say "Back soon"?

Accepted Answer

This product is listed but not currently in stock. It reflects an active restock plan rather than a discontinued listing: you can leave your email on this page and we will notify you as soon as the new batch arrives and has passed its own third-party test. We do not remove a product from the catalogue simply because a batch is between shipments, and we do not commit to a fixed restock date, since it depends on supplier lead times and on the outcome of that batch's own testing; the notification list is the fastest way to hear as soon as stock is confirmed.

Question 14

Where do you ship PT-141?

Accepted Answer

We ship EU-wide from within the EU, so there are no US customs issues for EU customers, and shipping is tracked via DHL from dispatch to delivery. Non-EU destinations such as Norway and the United Kingdom cross a customs border on the way and are shipped at the buyer's own import risk, including any local duties or clearance requirements. A few destinations are excluded for regulatory reasons, which is shown at checkout before you pay, and delivery times vary by destination and are shown alongside the shipping cost at that same step.

Question 15

Is PT-141 on the WADA prohibited list?

Accepted Answer

Peptide hormones and related compounds, including melanocortin receptor agonists, are broadly covered by anti-doping rules, and competitive athletes should assume this category is relevant to them rather than assume otherwise. The prohibited list is updated periodically, so athletes should check the current WADA list themselves rather than rely on this page. This material is in any case supplied for laboratory research only, not for human use, and certainly not for performance purposes.

Question 16

What form does PT-141 arrive in?

Accepted Answer

A lyophilized (freeze-dried) powder in a sealed vial, which is the standard form used across the published research. It can appear as a compact cake or a looser, flakier powder depending on how it settled during freeze-drying; this cosmetic variation does not indicate a change in purity or content, which is confirmed for each batch by its third-party certificate of analysis. It requires reconstitution with a suitable solvent before any laboratory use.

Question 17

How strong is the human clinical evidence, and who funded it?

Accepted Answer

The core efficacy evidence comes from two identical, randomised, double-blind, placebo-controlled phase 3 trials in premenopausal women with hypoactive sexual desire disorder (1267 participants combined), run and sponsored by the peptide's manufacturer (PMID 31599840). The integrated safety analysis across the full development programme, more than 3500 subjects across 43 studies, was also authored by the manufacturer's team (PMID 35147466). Later narrative reviews of bremelanotide (PMID 31893927, PMID 36242769) summarise this same manufacturer-generated dataset rather than adding independent trials. This is a genuine, randomised evidence base by the standards of this product category, but it is worth reading with knowledge of who designed, ran and funded almost all of it.

Question 18

What did the independent re-analysis of the phase 3 trials find?

Accepted Answer

An independent re-analysis of the phase 3 trial data (PMID 33678061) reproduces the manufacturer's headline efficacy estimates but is critical of the trials on two points: it argues that outcome reporting was selective, and it finds a considerably higher rate of adverse-event-related discontinuation on bremelanotide relative to placebo than the original publications emphasise. It does not dispute that a statistically significant difference from placebo was found; it disputes how the balance of benefit and side effects was presented. This kind of independent re-analysis is a normal and valuable part of the published record for any drug approval, not a sign that the original trials were fabricated, and reading both together gives a fuller picture than either alone.

Question 19

Do the effects seen in the phase 3 trials persist long term?

Accepted Answer

A 52-week open-label extension followed participants from the pivotal phase 3 trials with continued bremelanotide treatment beyond the original double-blind period (PMID 31599847), and prespecified subgroup analyses of the phase 3 data have also been published (PMID 35230162). These add longer-term and subgroup context, but the extension is open-label, without a placebo comparison, which limits how much can be concluded about durability of effect from it alone; a placebo group can also improve over time in this kind of trial, so an open-label result by itself cannot show how much of any persistence is specific to the drug.

Question 20

Why did development move from an intranasal to a subcutaneous formulation?

Accepted Answer

Early PT-141 studies tested intranasal dosing in both men and women, including a dose-response study (PMID 14963471) and a crossover trial combining intranasal PT-141 with sildenafil (PMID 15833522), alongside early subcutaneous dosing in men (PMID 14999221). Later development, including a phase 1 study examining coadministration with ethanol (PMID 28189361) and the pivotal phase 3 trials, used a subcutaneous formulation (PMID 31599840), which is also the route used by the approved US product. The published literature documents this shift in route but does not spell out a single stated reason for it.

Question 21

Does animal evidence always support a role in sexual behaviour?

Accepted Answer

No. Much of the animal literature cited for bremelanotide involves rodent studies showing hypothalamic neuronal activation or altered signalling (PMID 12851303, PMID 12172010), but not every animal study agrees. A hamster study found no change in melanocortin receptor expression and no change on a sexual reward measure after bremelanotide administration (PMID 39793696), a negative result worth weighing alongside the positive findings rather than assuming the animal evidence is uniform. Species and strain differences in melanocortin receptor biology are well documented, which is one reason findings do not always transfer even between two rodent species, let alone from rodents to humans.

Question 22

How does the proposed mechanism differ from PDE5 research compounds?

Accepted Answer

PDE5 research compounds work by blocking the breakdown of a signalling molecule in vascular smooth muscle, increasing blood flow to erectile tissue; that is a well-characterised, local, vascular mechanism. Bremelanotide's proposed mechanism is different in kind: it is a melanocortin receptor agonist, and review literature on the MC4R pathway (PMID 20190196) describes a role in central, hypothalamic circuits linked to sexual behaviour rather than direct vascular action. Unlike the PDE5 mechanism, the human mechanism behind bremelanotide's clinical effects has not been directly demonstrated; it is inferred from preclinical, mostly rodent, work.

Question 23

What does the melanocortin receptor family do more broadly?

Accepted Answer

The five melanocortin receptors (MC1R to MC5R) sit inside a broader neuropeptide signalling system, with roles described in the review literature spanning pigmentation, adrenal steroid production, energy balance and inflammation, alongside the sexual-function and feeding circuits relevant to bremelanotide (PMID 18996199, PMID 23851261). Other reviews of melanocortin ligands (PMID 25096243, PMID 36291616) cover the wider family of natural and synthetic compounds that act on these receptors, of which bremelanotide and Melanotan-II are two examples among many studied for different endpoints.

Question 24

What is known about blood pressure effects in the clinical trials?

Accepted Answer

The phase 3 and related clinical work documents a haemodynamic signal: transient increases in blood pressure after dosing (PMID 35147466). This is a significant part of why the approved US product carries restrictions against use in people with uncontrolled hypertension or known cardiovascular disease. A patient-experience exit study from the trial programme (PMID 33538638) also gathered qualitative feedback from participants on their own experience of treatment and its side effects, complementing the numerical safety data above.

Question 25

Does unrefrigerated shipping affect the quality of this product?

Accepted Answer

No. This product ships as a lyophilized (freeze-dried) powder in a sealed vial. Freeze-drying removes the water that drives peptide degradation, so the dry powder remains stable at room temperature for extended periods, longer than any normal parcel transit. Ambient shipping is standard practice across the peptide industry, and a peer-reviewed study reported months of room-temperature stability for a lyophilized therapeutic peptide (teriparatide, PMID 26620825). For comparison, FDA labeling allows an Ozempic (semaglutide) pen, after first use, to be kept out of the fridge for 56 days at 15 to 30°C, and a Mounjaro (tirzepatide) pen for up to 21 days at up to 30°C, even though these are ready-mixed solutions rather than sealed dry powder. Store the sealed vial in the fridge or freezer for long-term storage, and always refrigerate after reconstitution.

Question 26

Is there any evidence that Melanotan-2 or PT-141 restores libido lost while using a GLP-1/GIP peptide like Retatrutide, and has combining them been studied?

Accepted Answer

No trial, case series or pharmacovigilance study has tested a melanocortin agonist against GLP-1-associated libido loss, so the specific rescue scenario is unstudied end to end. What exists on each side: the GLP-1 libido signal itself is thin and mixed (rodent evidence for reduced sexual motivation, case reports, and a reporting-database analysis with a disproportionality ratio below 1, weak uncontrolled pharmacovigilance evidence, PMID 40240532; overall review PMID 41870138), and the proposed GLP-1 mechanisms (vascular, central dopaminergic or serotonergic) are competing hypotheses. On the melanocortin side, the erectile effect is genuinely documented: MT-2 produced erections in controlled crossover studies (PMID 11018622, PMID 11035391), with MC4R involvement as a mechanistic inference rather than a measured result, and PT-141 (bremelanotide) is US-FDA-approved as Vyleesi for acquired, generalized hypoactive sexual desire disorder in premenopausal women (no EU authorisation exists), and its label also quantifies the costs: nausea in 40 percent, flushing in 20 percent, and a transient blood-pressure rise of up to 6 mmHg systolic with each dose. But nothing shows these mechanisms address whatever a GLP-1 compound does to desire; treating one compound's side effect with a second compound is exactly the kind of interaction question that has never been studied for this pair, in any population. For PT-141 the PDE5 combination is not unstudied: a randomised crossover trial in 19 men with erectile dysfunction co-administered low-dose intranasal PT-141 with low-dose sildenafil and reported a significantly greater erectile response than sildenafil alone, with no new adverse events and none increased in frequency or severity versus monotherapy (PMID 15833522). That is one small study of an intranasal formulation that was later dropped in favour of the subcutaneous route, and the approved subcutaneous label (Vyleesi, DailyMed setid f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dcf) reports no PDE5 interaction data while warning of a transient blood-pressure rise after each dose. And MT-2 has no controlled blood-pressure dataset at community doses at all; its only detailed cardiovascular record is an overdose case report (PMID 23121206). The PT-141 evidence is limited to that small intranasal study, whereas combining MT-2 with a PDE5 inhibitor remains unstudied; neither finding supports a stacking recommendation.

Question 27

Does nasal-spray Melanotan or PT-141 work as well as the injectable form, and does it cause less nausea?

Accepted Answer

No head-to-head route comparison was identified, and the nasal-less-nausea belief finds no support in the one intranasal dataset identified. For PT-141, the early intranasal dose-response study itself lists nausea among the most common adverse events (PMID 14963471), while the approved subcutaneous product's label quantifies the injectable side: nausea in 40 percent versus 1.3 percent on placebo, flushing in 20.3 percent, vomiting in 4.8 percent (Vyleesi, US label). Different trials, different doses, different populations, so 'which route causes less' is formally unanswerable from these data, but nausea is documented separately on BOTH routes, so route-switching has no documented antiemetic advantage. Development history adds context: bremelanotide moved from intranasal to subcutaneous during development, and the approved product is the injection. For melanotan-2 the nasal question is even emptier: no human trial of nasal-spray MT-2 exists at all, while the subcutaneous pilots documented nausea and yawning as the recurring events (PMID 8637402, PMID 11018622, PMID 11035391). What a nasal product adds instead is a pharmaceutical unknown: peptide bioavailability through nasal mucosa is variable and formulation-dependent, and no verified bioavailability figure exists for either compound's spray form, so the actual delivered dose is guesswork. Route-switching to escape nausea is, on current evidence, a swap of documented side effects for undocumented dosing.

Question 28

My erections and testosterone are fine, it is desire that is low. Does PT-141 have data on desire itself in men, or only on erections?

Accepted Answer

The published endpoints separate desire from erection. Two RECONNECT phase 3 trials in premenopausal women with hypoactive sexual desire disorder used the Female Sexual Function Index desire domain and Female Sexual Distress Scale-Desire/Arousal/Orgasm item 13 as co-primary endpoints (PMID 31599840). Their integrated changes from baseline were 0.35 for sexual desire and -0.33 for distress compared with placebo. In healthy male subjects, a bremelanotide study reported a statistically significant erectile response at doses greater than 1.0 mg, an erectile endpoint rather than a desire endpoint (PMID 14999221). A different compound, Melanotan-2, increased reported desire after 13 of 19 doses, 68 percent, compared with 4 of 21 placebo doses, 19 percent, in 20 men with psychogenic or organic erectile dysfunction (P less than 0.01; PMID 11035391). As of 2026-09-04, no completed study has reported a sexual-desire endpoint for bremelanotide in men (PubMed search: 'bremelanotide AND (sexual desire OR libido) AND (men OR male)'; ClinicalTrials.gov search: 'bremelanotide OR PT-141'). A commentary still poses that use as a question (PMID 41960633). The US prescribing information for the approved bremelanotide product records under Limitations of Use that it is not indicated for the treatment of HSDD in postmenopausal women or in men. We cannot interpret an individual's low desire or recommend a compound or dose.

Question 29

How often was bremelanotide dosed in the phase 3 trials, and does the approved US label cap how many doses are taken per day and per month?

Accepted Answer

These are label figures for an approved medicine, not a protocol for this research material. The US label for the approved subcutaneous product describes 1.75 mg subcutaneously as needed, at least 45 minutes before anticipated sexual activity, and sets two limits: not more than one dose within 24 hours, and administering more than 8 doses per month is not recommended (Vyleesi, bremelanotide injection, DailyMed setid f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dcf, section 2.1). The label states that the efficacy of consecutive doses within 24 hours has not been established and that administering doses close together may increase the risk of additive effects on blood pressure. On pigmentation the same label reports focal hyperpigmentation in 1% of patients who received up to 8 doses per month, compared to no placebo-treated patients, and in 38% of patients after daily dosing for 8 days in another clinical study (section 5.2). In phase 3, the protocol allowed up to 12 doses per month, the median was 10 injections over the 24-week double-blind period, and most patients used two to three doses per month and no more than once weekly (section 14).

Question 30

At what intranasal dose did PT-141 reach a statistically significant erectile response, and how does that compare with the subcutaneous doses studied?

Accepted Answer

Two separate early studies, not a head-to-head route comparison. Intranasal PT-141 produced a statistically significant erectile response versus placebo at doses greater than 7 mg, with onset of the first erection at approximately 30 minutes, median Tmax of 0.50 h and mean half-life of 1.85 to 2.09 h; in healthy subjects mean Cmax and AUC increased in a dose-dependent manner (PMID 14963471). The subcutaneous study gave doses ranging from 0.3 to 10 mg to healthy male subjects and found a statistically significant erectile response at doses greater than 1.0 mg, and in ED patients treated with placebo, 4 or 6 mg in a crossover design the response was statistically significant at both doses (PMID 14999221). The approved subcutaneous product is dosed at 1.75 mg (Vyleesi, DailyMed setid f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dcf, section 2.1). The published intranasal threshold therefore sits several times higher in milligrams than the subcutaneous one, although the two studies used different populations and conditions, which limits any direct comparison. These are clinical-trial findings, not a protocol for this research material.

PT-141

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