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Lexicon
Sexual function

PT-141

A melanocortin agonist for sexual function. Acts centrally via the brain, not via blood flow.

3 min read 11 sources

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Still from the explainer video about this entry
Compound approved · in the USA since 2019Lab tested in the shop

No time to read it all? The video sums up the whole entry in about a minute, from how it works to the studies and storage.

Summary

At a glance

Sources checked on 26 Oct 2026

Phase 3 in the registry
3 trials

all completed, two of them the approval trials, as of 26 Oct 202611

Desire in phase 3
+0.35 points

more than on placebo, FSFI questionnaire, both trials combined1

Half-life
~2.7 hours

after one dose under the skin, peak level after about 1 hour9

Nausea
40 %

most common side effect in phase 3 (placebo 1.3%)4

  • PT-141 (drug name bremelanotide) is a ring-shaped peptide of seven amino acids that activates melanocortin receptors, above all MC1R and MC4R.910
  • In two phase 3 trials (RECONNECT, 24 weeks) premenopausal women with low sexual desire saw desire rise more than on placebo and distress fall more.1
  • Bremelanotide has been approved in the USA since 2019, only for women before menopause with acquired, generalised low desire. The approval does not cover men or women after menopause.98
  • The most common effects were nausea, facial flushing and headache. Blood pressure rose slightly for a short time after a dose.45
  • Everything here is the state of research, not a recommendation.9
Profile

Updated May 2026

Class
Melanocortin agonist

bremelanotide

Route
Subcutaneous

on demand

Timing
About 45 minutes before
Form
Lyophilised powder

reconstituted with BAC water

Sizes
5 to 30 mg

3 sizes in the shop

Contents 16 sections
  1. At a glance
  2. What is PT-141?
  3. How it works
  4. What you need
  5. Reconstitution
  6. Injection
  7. Dosing
  8. What the research shows
  9. Research status
  10. Side effects
  11. Practice
  12. Storage
  13. Related compounds
  14. FAQ
  15. Glossary
  16. Sources

What is PT-141?

PT-141 (active name bremelanotide) is a melanocortin agonist and related to Melanotan II, but for a different purpose. While Melanotan II is mainly known for skin tanning, PT-141 is used for sexual function and is even approved as a medicine for it.

The key difference from agents like PDE-5 inhibitors: PT-141 acts centrally via the brain (desire), not via blood flow. It is used subcutaneously on demand. It ships as a freeze-dried powder you dissolve in bacteriostatic water.

Comparison

Melanocortin peptides and other paths

Which receptors each compound targets, as stated in the TPD lexicon. Tap a card to open its entry.

Melanocortin agonist, tanning Melanotan 1 MC1R MC4R 1 of 2 receptors Melanocortin agonist, broad Melanotan II MC1R MC4R 2 of 2 receptors
Melanocortin agonist, approved PT-141 MC1R MC4R 2 of 2 receptors
PDE-5 inhibitor Sildenafil MC1R MC4R 0 of 2 receptors

Simplified from the lexicon entries. Melanotan II acts on further melanocortin receptors, PDE-5 inhibitors act via blood flow instead of the brain. 9

How it works

PT-141 activates melanocortin receptors in the brain, mainly the MC4 receptor, which is involved in regulating sexual desire. So the effect runs through the central nervous system and the sense of desire, not through the vessels. That is why it can work even when purely blood-flow-related agents miss the point.

Unlike Melanotan II, PT-141 is not designed for tanning; skin pigmentation is not the focus here.

Where it acts

Where PT-141 acts

Tap a point or a card. Colour = receptor, grey = seen in studies.

  1. Brain

    Nerve cells with MC4R in many brain regions, how the effect arises is unknown according to the label9

    MC4R
  2. Skin

    More pigment, rarely dark patches, more often with daily dosing4

    MC1R
  3. Stomach

    Nausea in 40% in phase 3, weaker from the second dose for most9

    Observed in trials
  4. Blood pressure

    Briefly up to 3 mmHg higher, heart rate somewhat lower5

    Observed in trials
  5. Appetite and weight

    In phase 1 trials in obesity about 400 kcal less per day and 1.3 kg more loss than on placebo in 16 days6

    Observed in trials

Targets in the ChEMBL database10

Compound CHEMBL2070241: two recorded mechanisms, type of action on each card.

Melanocortin 4 receptor
Gene
MC4R
UniProt
P32245
ChEMBL
CHEMBL259
Action
Agonist, direct binding (mechanism in ChEMBL)
Melanocortin 1 receptor
Gene
MC1R
UniProt
Q01726
ChEMBL
CHEMBL3795
Action
Agonist according to the label, most strongly activated
Transparent glass structure with branching pathways and bright nodes, blue molecule chains docking at two points
Melanocortin receptors on nerve cells. Symbolic image.

What you need

For subcutaneous use you need:

Supplies

5 things, numbered as in the picture

Tick off what you already have. Vial and BAC water are our real shop photos at the same size.

PT-141 vial and bacteriostatic water at the same size with the black TPD label, next to two U-100 insulin syringes, two alcohol swabs and a sharps container with a blue lid

  1. PT-141 vial

    The PT-141 vial with the freeze-dried powder

    In the shop

  2. Bacteriostatic water

    Bacteriostatic water to dissolve it

    In the shop

  3. U-100 insulin syringes

    U-100 insulin syringes

    Amazon (opens a new tab)

  4. Alcohol swabs

    Alcohol swabs for the vial cap and the skin

    Amazon (opens a new tab)

  5. Sharps container

    A sealable sharps container for used needles

As an Amazon associate we earn from qualifying purchases. Links open Amazon - no extra cost for you.

Reconstitution

The powder is dissolved in bacteriostatic water. How much water you add sets the concentration and therefore how many units you draw for your dose on the insulin syringe.

Use the peptide calculator for this: pick the water volume to see the concentration and units per dose.

When dissolving, just add the bac water, it does not matter if it hits the powder directly. Then swirl or shake until everything has dissolved, both are fine.

Step by step

Dissolving the powder

Four steps, the same for every vial size.

  1. 1Wipe the cap

    Clean the rubber stopper with an alcohol swab.

  2. 2Add BAC water

    Just add it, it does not matter if it hits the powder directly.

  3. 3Swirl or shake

    Until everything has dissolved, both are fine.

  4. 4Draw up

    With the U-100 insulin syringe.

Less water higher concentration fewer units on the syringe Example: 10 mg + 2 ml = 5 mg/ml

Injection

The injection is subcutaneous, into the fat layer under the skin, about 45 minutes before the desired effect. Typical spots are the abdomen (keep clear of the area around the navel), the front and the inner side of the thigh or the back of the upper arm.

Injection

Where and at what angle

Pick a spot or switch the angle. Subcutaneous means: into the fat layer, not the muscle.

Rotate the spot each time, never the same one twice in a row.

90°More fat under the skin

Rule of thumb: where there is more fat under the skin, insert straight at 90 degrees. In lean people with little fat, 45 degrees, so the needle stays in the fat layer. Simplified diagram.

  1. Clean the spot with an alcohol swab and let it dry

  2. Pinch up a small fold of skin

  3. Insert the needle: at 90 degrees where there is more fat under the skin, at 45 degrees in lean people with little fat

  4. Inject slowly, wait a moment, then withdraw

  5. Put the needle straight into the sharps container

Rotate the site.

Dosing

Dosing

Dosing, titration and syringe

Loading the dosing information …

  • Getting started and stepping up, drawn as a staircase
  • Units on the U-100 syringe for every step
  • How long one vial lasts

What the research shows

PT-141 is one of the best-evidenced of the substances listed here: two large randomised phase 3 trials (RECONNECT) showed, in premenopausal women with reduced sexual desire, a statistically significant improvement in desire and a reduction in the related distress versus placebo. On this basis bremelanotide was approved.

The study with a link is in the source block below.

Study results

What the trials measured

Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.

Desire after 24 weeks1

More than on placebo, in points on the desire part of the FSFI questionnaire

Trial 3011
Bremelanotide (approved dose) +0.30%
Trial 3021
Bremelanotide (approved dose) +0.42%
Both combined1
Bremelanotide (approved dose) +0.35%

Difference from placebo according to the abstract, all statistically significant. 1,202 women in the analysis, dosed on demand.

Distress after 24 weeks1

Less than on placebo, in points on one item of the FSDS-DAO questionnaire

Trial 3011
Bremelanotide (approved dose) -0.37%
Trial 3021
Bremelanotide (approved dose) -0.29%
Both combined1
Bremelanotide (approved dose) -0.33%

Difference from placebo according to the abstract. What was measured is distress about low desire.

Change after 12 weeks3

Mean change from baseline, 327 women in the analysis

FSFI questionnaire total3 Points, higher is better
Placebo +1.9%
Middle and highest level combined +3.6%
FSDS-DAO distress total3 Points, lower is better
Placebo -6.8%
Middle and highest level combined -11.1%
Satisfying events per month3
Placebo +0.2%
Middle and highest level combined +0.7%

Values from the abstract. The trial tested three levels, the abstract reports the two higher ones combined.

Clear glass brain on a bright surface, circled by a glowing pink light trail
Two approval trials with 1,267 women in total. Symbolic image.

Research status

Where the research stands

From the first trials to approval in the USA: registered trials with status, participants and results. As of 26 Oct 2026. 11

  1. Preclinical Animal models and early trials with nasal dosing
  2. Phase 1 1 trial, 1 completed
  3. Phase 2 3 trials, 2 completed
  4. Phase 3 3 trials, 3 completed
  5. Approval in the USA since 2019
1,630 participants in phase 3 Approved in the USA since 2019, only for women before menopause with acquired, generalised low desire (HSDD). ChEMBL lists bremelanotide with phase 4 as the highest phase.9
Show all 8 phase 2, 3 and 4 trials on a timelineHide timeline 7 completed 1 running 3 with results
Phase 2
Phase 3
Phase 4

Bar: start to primary endpoint (planned for running trials). Green = completed, blue = progress until 26 Oct 2026. Phase 1: 1 trial on safety and pharmacokinetics, not shown as bars.

Side effects

The most common side effect is nausea, especially at higher doses and at the start. On top come facial flush (heat, redness) and headache. In the studies a transient, slight rise in blood pressure was observed, which is why starting low and not dosing too often makes sense.

Tolerability

Frequency in phase 3

Out of 100 participants per group, how many had the event over 24 weeks.

1 of 100 Placebo
40 of 100 Bremelanotide (approved dose)
Event PlaceboBremelanotide (approved dose)
Nausea4 1%40%
Facial flushing4 1%20%
Headache4 2%11%
Injection site reaction4 1%5%

Values according to the abstract, 1,247 women. Nausea was the most common reason for stopping. Blood pressure rose slightly in the first hours after a dose, heart rate fell somewhat.45

Practice

  1. Start low and gauge tolerability (especially nausea).

  2. Plan about 45 minutes of lead time.

  3. Not too often, it is an on-demand agent, not a daily one.

Two glasses of sparkling water, an hourglass, a lit white candle and flowers on a light table by the window

Storage

The undissolved powder is robust, normal room temperature (around 20 to 25 degrees) is fine, ideally kept in the dark. The reconstituted solution goes into the fridge (2 to 8 degrees) and stays stable there for at least 4 to 6 months with barely any loss of potency, in practice considerably longer. The bacteriostatic water brings a preservative that keeps the dissolved form stable for longer.

Shelf life

How long it keeps

Undissolved (powder) Room temperature, around 20 to 25 degrees, dark

Robust, no fridge needed.

Dissolved (mixed) Fridge, 2 to 8 degrees

At least 4 to 6 months with barely any loss of potency. The bacteriostatic water brings a preservative.

  • Keep it dark
  • Dissolved: 2 to 8 degrees
  • Note the mixing date on the vial
Nine vials with white powder and blue caps in the door shelf of a bright fridge
Powder dark at room temperature, once dissolved into the fridge (2 to 8 degrees), stable there for at least 4 to 6 months. Symbolic image.

Related

Related compounds

Same receptors, blends with PT-141 or a different path: all in the TPD lexicon.

PT-141
PT-141 Nasal Spray The same substance as a nasal spray Melanotan II Related precursor, known for tanning Melanotan 1 MC1R only, tanning Kisspeptin-10 Different path: reproductive hormone axis Oxytocin Acetate Different path: bonding hormone Sildenafil Different path: blood flow Tadalafil Different path: blood flow

FAQ

Common questions about PT-141

Short answers, each backed by the sources below.

Is PT-141 approved?

Yes, as bremelanotide in the USA since 2019. The approval is narrow: women before menopause with acquired, generalised low sexual desire that causes distress. Not for men, not after menopause and according to the label not to enhance sexual performance.98

How does PT-141 differ from PDE-5 inhibitors?

The point of action. PDE-5 inhibitors act via blood flow. Bremelanotide activates melanocortin receptors, including MC4R on nerve cells in the brain. How this leads to more desire is not clear according to the label.910

What did the phase 3 trials show?

In two trials with 1,267 women in total, desire rose by 0.35 points more than on placebo after 24 weeks and distress fell by 0.33 points more. Both were statistically significant. In the open extension over 52 weeks the values stayed stable.12

How long does PT-141 stay in the body?

After one dose under the skin the level peaks after about one hour, the half-life is about 2.7 hours. That fits use on demand, as the entry describes.9

Which side effects were seen?

Most often nausea (40 percent versus 1.3 percent on placebo), facial flushing (20 percent) and headache (11 percent). Nausea was the most common reason for stopping. Blood pressure rose by a few mmHg for a short time after a dose.45

What about dark patches on the skin?

Via MC1R bremelanotide stimulates pigment formation. Patchy darkening, including on the face and gums, was rare with dosing according to the label (about 1 percent). After up to 16 doses on consecutive days it occurred in more than a third and did not resolve in everyone.94

Glossary

Terms explained briefly

Dotted words in the text open these explanations directly.

Agonist
A substance that binds to a receptor and activates it, like the body's own messenger.
Half-life
Time after which only half of a substance is left in the blood.
HSDD
Hypoactive sexual desire disorder: persistently low sexual desire that causes distress and has no other cause.
Lyophilisate
Freeze-dried powder. Without water a peptide keeps much longer.
MC1R
Melanocortin 1 receptor on pigment cells. It controls how much melanin the skin makes.
MC4R
Melanocortin 4 receptor on nerve cells in the brain, involved in satiety and sexual desire.
Melanocortins
The body's own messengers such as alpha-MSH. Their five receptors control skin colour, appetite and sexual desire among other things.
PDE-5 inhibitor
Drug group such as sildenafil and tadalafil that acts through more blood flow, not through desire.
Placebo
Dummy preparation without active substance. Comparing against it shows what is due to the substance itself.
Premenopausal
Before menopause, with periods still occurring regularly.
Subcutaneous
Into the fat layer just under the skin.

Evidence

Sources

Show all 11 sourcesHide sources 8 Studies1 Trial registry2 Database checked 26 Oct 2026

Studies

  1. Two phase 3 trials RECONNECT in low desire

    Kingsberg et al., Obstetrics & Gynecology, 2019

    DOI 10.1097/AOG.0000000000003500 PMID 31599840 NCT02333071
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  2. Open extension over 52 weeks

    Simon et al., Obstetrics & Gynecology, 2019

    DOI 10.1097/AOG.0000000000003514 PMID 31599847
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  3. Phase 2 dose-finding trial

    Clayton et al., Women's Health, 2016

    DOI 10.2217/whe-2016-0018 PMID 27181790 NCT01382719
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  4. Safety profile across the whole trial programme

    Clayton et al., Journal of Women's Health, 2022

    DOI 10.1089/jwh.2021.0191 PMID 35147466
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  5. Blood pressure measured over 24 hours

    White et al., Journal of Hypertension, 2017

    DOI 10.1097/HJH.0000000000001221 PMID 27977473
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  6. Two phase 1 trials on weight in obesity

    Spana et al., Diabetes, Obesity and Metabolism, 2022

    DOI 10.1111/dom.14672 PMID 35170192
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  7. Early trial with nasal dosing

    Diamond et al., Journal of Sexual Medicine, 2006

    DOI 10.1111/j.1743-6109.2006.00268.x PMID 16839319
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed
  8. Review of the first approval

    Dhillon et al., Drugs, 2019

    DOI 10.1007/s40265-019-01187-w PMID 31429064
    Checked 26 Oct 2026 via doi.org, Crossref, PubMed

Trial registry

  1. All trials on ClinicalTrials.gov

    ClinicalTrials.gov, U.S. National Library of Medicine

    Checked 26 Oct 2026 via ClinicalTrials.gov API v2

Database

  1. US prescribing information (approval, mechanism, side effects)

    DailyMed, U.S. National Library of Medicine, Fassung November 2025

    Checked 26 Oct 2026 via DailyMed
  2. Mechanism and target in ChEMBL

    ChEMBL, EMBL-EBI (CHEMBL2070241)

    Checked 26 Oct 2026 via ChEMBL

In the shop

PT-141 in the catalog

Sizes, prices and shipping times are on the product page.

To the product