PT141, also known as bremelanotide or Vyleesi®, is a synthetic peptide that bears structural similarity to alpha melanocyte-stimulating hormone (α-MSH). Just like α-MSH, PT141 stimulates melanocortin receptors.

There are 5 melanocortin receptors, MC1R-MC5R, each of which is associated with a set of activities. PT141 works primarily by activating the MC4 receptor, which not only affects sexual function but also regulates appetite, energy expenditure, and exerts neuroprotective and anti-inflammatory effects. Additionally, it activates, to a lesser degree, MC3R, which is responsible for regulating energy homeostasis, metabolism and feeding behaviour.

Although it can exert a broad range of benefits, research on this compound has focused predominantly on its ability to treat sexual dysfunction.

Causes and Impact of Sexual Dysfunction in Men and Women

PT141 has been approved for the treatment of hypoactive sexual desire disorder (HSDD) and female sexual arousal disorder (FSAD) in premenopausal women, both of which are a type of female sexual dysfunction (FSD). It is being investigated as a treatment for erectile dysfunction in men with ED who do not respond to phosphodiesterase 5 inhibitors (PDE5-Is).

Before covering how this peptide can benefit those suffering from these problems, we’ll take a closer look at these disorders, who they affect and what might be causing them.

Women with Female Sexual Dysfunction

Female sexual dysfunction is a common problem, affecting approximately 40% of adult women¹. The main symptoms include persistently low sexual desire, lack of sexual arousal, difficulty reaching orgasm, pain during intercourse and personal distress.

There are multiple risk factors for FSD, including:

Aging: Although sexual desire in women tends to increase with age, younger women are generally more distressed by their lack of sexual desire².
Health factors: Metabolic syndrome and diabetes lead to an increased risk due to the broad effects that dysregulated lipid and glucose levels can have on the body^3,4.
Certain medications: Some drugs such as antihypertensive medications, SSRIs and antipsychotics can increase the risk of developing FSD⁵.
Psychological factors: Depression, stress and other negative emotional states all contribute to a significant increase in risk⁶.

FSD leads to a lower quality of life, lower relationship satisfaction and negative emotional states. Although this problem affects such a large number of people worldwide, it is unfortunately not well recognised and undertreated.

Men with Erectile Dysfunction

Erectile dysfunction is relatively more common than HSDD, affecting about 52% of some populations of men. The prevalence increases with age, with even higher rates being seen in men over the age of 70⁷.

The risk factors for ED are:

Aging: the older a man is, the more likely he is to suffer from erectile dysfunction⁸.
Chronic diseases: Diabetes, cardiovascular disease and neurological diseases all increase risk⁹.
Depression: Those suffering from depression are far more likely to also suffer from sexual dysfunction¹⁰.
Certain medications: Antihypertensive drugs¹¹, SSRIs¹² and drugs used to treat prostate conditions¹³ are examples of some of the types of drugs that have been linked to ED in men.
Lifestyle factors: Smoking can increase the chance of developing erectile dysfunction by approximately 50%¹⁴, while being obese can increase the risk by about 60%¹⁵.
Low testosterone levels: Up to 17% of young men with ED also have low testosterone¹⁶.

This condition can have a significant negative impact on quality of life, yet up to 70% of men with erectile dysfunction do not receive treatment¹⁷.

PT141 as a Treatment of Sexual Dysfunction

PT141 has been investigated in animals and humans to explore its mechanism of action and efficacy as a medicine to treat sexual dysfunction.

Research has reported that it increases sexual desire and arousal by targeting MC4 receptors in the brain. This is thought to increase the release of dopamine, which plays an important role in sexual excitement and motivation¹⁸, making it useful in treating low sexual desire. Distinct differences in the success of this drug in treating sexual dysfunction in men with ED and pre- and postmenopausal women with FSD have been noted in research.

How Does PT141 Help Women with FSD?

As a treatment for FSD in premenopausal women, PT141 has demonstrated a significant ability to improve:

Sexual desire
Arousal
Orgasm¹⁹

The benefits of this peptide can be seen within the first month of using it and continue to improve. Those who have used PT141 also report reduced distress related to low sexual desire and improvement in the quality of sex and their relationship.

Its effects are considered significant, but modest. The placebo effect alone can provide some benefit, but with PT141, a greater improvement is seen^20,21.

How Does PT141 Help Men with Erectile Dysfunction?

The mechanism by which PT141 affects men is well understood and there is clear evidence that it can help to improve sexual function²². In men with erectile dysfunction, there have been reported improvements in:

Sexual function
Satisfaction
Confidence²³

A recent article reported that most men with ED who used PT141 experienced improvements in sexual function, such as better erections, longer erections and greater enjoyment of sex. This study also noted that men were most likely to use it repeatedly when compared to pre- and postmenopausal women, with premenopausal women being the least likely to fill a repeat prescription²³.

Dosing

When researchers tested oral PT141 on dogs, only a very minimal amount was absorbed, demonstrating that this is an inefficient method of delivery. Intranasal administration requires higher doses (20mg), making subcutaneous injection the preferred method of administration.

For the treatment of HSDD and FSAD in premenopausal women and ED in men, the recommended dose is 1.75mg, administered subcutaneously in the abdomen or thigh, approximately 45 minutes before sex. This can be given as needed but is restricted to one dose per 24 hours and less than 8 doses per month.

Adverse Effects

PT141 is considered to be generally safe and well-tolerated, but it is associated with several adverse events, such as:

Nausea
Flushing
Headache
Injection site reactions^19,23

Nausea is the main cause for discontinuation, but it lessens in severity with subsequent doses.

Other rarer side effects include vomiting, a transient increase in blood pressure, a decrease in heart rate and darkening of the skin²⁴.

Due to the effect that PT141 can have on blood pressure, it is not recommended for people with uncontrolled hypertension or cardiovascular disease²⁵. It can also reduce the effectiveness of oral naltrexone and indomethacin as these drugs are typically taken orally and PT141 can slow gastric emptying, thus reducing their concentrations in the blood. It has not been studied in pregnant women, so is not recommended for those who are pregnant or trying to conceive.

Alternatives

Female Sexual Dysfunction

Flibanserin (Addyi®) is the only alternative drug for women with HSDD and FSAD. This works as a serotonin receptor modulator, increasing levels of dopamine and norepinephrine to promote sexual desire, while lowering serotonin. Commonly experienced adverse effects include dizziness, sleepiness, nausea, fatigue, insomnia and dry mouth^26,27.

There are non-pharmacological ways to improve sexual desire in women, depending on the cause, including:

Behavioural therapy and couples therapy
Lifestyle changes that promote healthy levels of activity and minimise unhealthy habits
Pelvic floor physiotherapy

Erectile Dysfunction

For erectile dysfunction, PDE5 inhibitors such as sildenafil (Viagra®), tadalafil (Cialis®), vardenafil (Levitra®) and avanafil (Spedra®) are the most prescribed type of drug. These work by inhibiting the enzyme PDE5 which degrades cGMP, a compound essential for bringing about and maintaining an erection. Commonly experienced side effects include headache, flushing, indigestion, nasal congestion, back and muscle pain, nausea, dizziness and rash^28,29.

Other interventions include:

Vacuum erection devices
Lifestyle changes such as increasing exercise and reducing alcohol intake.
Counselling, if the cause is due to emotional or psychological issues.
Prosthesis implants

Conclusion

Both FSD and ED are common issues that can have multiple contributing causes. Treatments include medications and lifestyle changes.

PT141 significantly improves FSD in premenopausal women, and although it is not approved for use in postmenopausal women, there is evidence that this population may also benefit from it. The research on PT141 in men is lacking in comparison, but the work so far shows that it may be an effective treatment for sexual dysfunction in men.

Buy PT141 here.

References

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Hayes RD, Dennerstein L, Bennett CM, Koochaki PE, Leiblum SR, Graziottin A. Relationship between hypoactive sexual desire disorder and aging. Fertil Steril. 2007;87(1):107-112. doi:10.1016/j.fertnstert.2006.05.071
Navriya SC, Jain M, Yadav O, Chowdary RC. Sexual Dysfunction in Female Patients with Diabetes. In: Feingold KR, Ahmed SF, Anawalt B, et al., eds. Endotext. MDText.com, Inc.; 2000. Accessed October 29, 2025. http://www.ncbi.nlm.nih.gov/books/NBK612823/
Martelli V, Valisella S, Moscatiello S, et al. Prevalence of Sexual Dysfunction Among Postmenopausal Women with and Without Metabolic Syndrome. J Sex Med. 2012;9(2):434-441. doi:10.1111/j.1743-6109.2011.02517.x
Pachano Pesantez GS, Clayton AH. Treatment of Hypoactive Sexual Desire Disorder Among Women: General Considerations and Pharmacological Options. Focus. 2021;19(1):39-45. doi:10.1176/appi.focus.20200039
Basson R, Gilks T. Women’s sexual dysfunction associated with psychiatric disorders and their treatment. Womens Health. 2018;14:1745506518762664. doi:10.1177/1745506518762664
Melman A, Gingell JC. The Epidemiology and Pathophysiology of Erectile Dysfunction. J Urol. Published online January 1999. doi:10.1016/S0022-5347(01)62045-7
Selvin E, Burnett AL, Platz EA. Prevalence and Risk Factors for Erectile Dysfunction in the US. Am J Med. 2007;120(2):151-157. doi:10.1016/j.amjmed.2006.06.010
Bortolotti A, Parazzini F, Colli E, Landoni M. The epidemiology of erectile dysfunction and its risk factors. Int J Androl. 1998;20(6):323-334. doi:10.1046/j.1365-2605.1998.00081.x
Zhang F, Xiong Y, Wu K, Zhang B. Assessment of the causal link between depression and erectile dysfunction: A Mendelian randomization study. Asian J Surg. 2023;46(12):5533-5534. doi:10.1016/j.asjsur.2023.07.145
Düsing R. Sexual Dysfunction in Male Patients with Hypertension. Drugs. 2005;65(6):773-786. doi:10.2165/00003495-200565060-00005
Philipp M, Tiller JWG, Baier D, Kohnen R. Comparison of moclobemide with selective serotonin reuptake inhibitors (SSRIs) on sexual function in depressed adults. Eur Neuropsychopharmacol. 2000;10(5):305-314. doi:10.1016/S0924-977X(00)00085-7
Favilla V, Russo GI, Privitera S, et al. Impact of combination therapy 5-alpha reductase inhibitors (5-ARI) plus alpha-blockers (AB) on erectile dysfunction and decrease of libido in patients with LUTS/BPH: a systematic review with meta-analysis. Aging Male. 2016;19(3):175-181. doi:10.1080/13685538.2016.1195361
Cao S, Yin X, Wang Y, Zhou H, Song F, Lu Z. Smoking and Risk of Erectile Dysfunction: Systematic Review of Observational Studies with Meta-Analysis. Baradaran HR, ed. PLoS ONE. 2013;8(4):e60443. doi:10.1371/journal.pone.0060443
Pizzol D, Smith L, Fontana L, et al. Associations between body mass index, waist circumference and erectile dysfunction: a systematic review and META-analysis. Rev Endocr Metab Disord. 2020;21(4):657-666. doi:10.1007/s11154-020-09541-0
Alla SR, Ambujam G. Erectile Dysfunction and Testosterone Deficiency in Young Men: A Retrospective Study. Recent Dev Med Med Res Vol 15. Published online November 23, 2021:120-124. doi:10.9734/bpi/rdmmr/v15/14260D
Burnett AL, Rojanasarot S, Amorosi SL. An Analysis of a Commercial Database on the Use of Erectile Dysfunction Treatments for Men With Employer-Sponsored Health Insurance. Urology. 2021;149:140-145. doi:10.1016/j.urology.2020.11.051
Pfaus J, Giuliano F, Gelez H. Bremelanotide: An Overview of Preclinical CNS Effects on Female Sexual Function. J Sex Med. 2007;4:269-279. doi:10.1111/j.1743-6109.2007.00610.x
Clayton AH, Althof SE, Kingsberg S, et al. Bremelanotide for Female Sexual Dysfunctions in Premenopausal Women: A Randomized, Placebo-Controlled Dose-Finding Trial. Womens Health. 2016;12(3):325-337. doi:10.2217/whe-2016-0018
Cipriani S, Alfaroli C, Maseroli E, Vignozzi L. An evaluation of bremelanotide injection for the treatment of hypoactive sexual desire disorder. Expert Opin Pharmacother. 2023;24(1):15-21. doi:10.1080/14656566.2022.2132144
Goldstein I, Rubin R, Kingsberg S, et al. (122) Positive Effects of Bremelanotide on Female Sexual Arousal And Orgasm in Premenopausal Women With HSDD: FSFI Data from the Reconnect Trials. J Sex Med. 2025;22(Supplement_1):qdaf068.108. doi:10.1093/jsxmed/qdaf068.108
King SH, Mayorov AV, Balse-Srinivasan P, Hruby VJ, Vanderah TW, Wessells H. Melanocortin Receptors, Melanotropic Peptides and Penile Erection. Curr Top Med Chem. 2007;7(11):1098-1106.
Goldstein S, Goldstein I. (035) Use of Bremelanotide in Men with Sexual Dysfunction at a Sexual Medicine Clinic. J Sex Med. 2024;21(Supplement_6):qdae161.029. doi:10.1093/jsxmed/qdae161.029
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Which SARM is the best for muscle gain?

It can be difficult to determine which SARMs are best for lean muscle building because different body types respond differently to them. Almost all SARMs boost muscle gain, but some have a stronger effect than others.

Top-tier SARMs for muscle gain include:

Test RAD-140
Ibutamoren MK-677
Ostarine MK-2866

Compared to some other brands, they also offer really good performance. RAD-140, Ostarine, and MK-677 are well-known for boosting muscle growth explosively and making gaining muscle much easier.

If you want to gain a lot of muscle quickly, consider using one of the above SARMs.

Do SARMs have side effects?

SARMs’ side effects are generally fewer and less serious than those of anabolic steroids. Still, using SARMs supplement products does have a small risk of complications.

Some side effects that have been reported include:

Diarrhoea
Headaches
Hypertension
Heart disease
Aggression
Acne

It is important to remember that the severity and presence of a side effect will likely depend on both dosage and the specific SARM taken.

Why should I use SARMs?

Burning fat
Bulking or cutting
Improving performance
Decreased recovery time
Building lean body mass
Increasing bone density

What are SARMs?

SARMs, or selective androgen receptor modulators, are relatively new drugs that attach to your body’s androgen receptors, triggering changes in your DNA, which in turn increases your muscles’ ability to grow. Unlike steroids, they target specific types of tissues and don’t come with side effects like breast growth in males.

They combat muscle loss caused by age, osteoporosis, disease, and building muscle and bone. Due to their ability to improve strength with fewer side effects than steroids, dietary supplement brands have started selling them to athletes.

Because they’re anabolic agents that enhance performance, SARMs are on the World Anti-Doping Agency’s list of prohibited substances.

What should I consider before I buy SARMs in the UK?

Before you buy SARMs in the UK, it’s important to consider factors such as product purity, third-party testing, and supplier transparency. UK SARMs is committed to providing high-quality research compounds with clear labelling and lab reports available. Always ensure you’re purchasing from a trusted source that complies with UK regulations.