Last Updated January 31, 2024

 January 31, 2024

Researchers may be interested in a comprehensive comparison between PT-141 nasal spray vs. injections.

PT-141 is a synthetic peptide that activates specific receptors in the brain and has been shown to cause a dramatic increase in sex drive in both men and women.

This article will compare the two main PT-141 formats used in research settings to induce benefits like:

  • Improved sexual desire
  • Better erections in men
  • Appetite suppression

Readers will also discover detailed information about the peptide’s mechanisms and side effects, as well as where to source high-quality PT-141 as a reference material.

Buy PT-141 Nasal Spray from our top-rated vendor...

Disclaimer: contains information about products that are intended for laboratory and research use only, unless otherwise explicitly stated. This information, including any referenced scientific or clinical research, is made available for educational purposes only. Likewise, any published information relative to the dosing and administration of reference materials is made available strictly for reference and shall not be construed to encourage the self-administration or any human use of said reference materials. makes every effort to ensure that any information it shares complies with national and international standards for clinical trial information and is committed to the timely disclosure of the design and results of all interventional clinical studies for innovative treatments publicly available or that may be made available. However, research is not considered conclusive. makes no claims that any products referenced can cure, treat or prevent any conditions, including any conditions referenced on its website or in print materials.

What is PT-141?

PT-141 (alternatively, bremelanotide) is a synthetic cyclic heptapeptide that emulates the function of α-melanocyte stimulating hormone (alpha-MSH), a hormone mainly secreted by the pituitary gland [1].

Alpha-MSH interacts with various melanocortin receptors (MCRs) in the body, affecting multiple physiological processes. There are five identified MCRs, and PT-141 activates all of these receptors excluding MC2R, which is found in the adrenal glands.

Here is a summary of the primary effects of MCR receptor activation by PT-141 [2]:

  • Skin Pigmentation: Interaction with MC1R in the skin enhances melanin production, leading to tanned skin.
  • Sexual Function: Activation of MC3R and MC4R has a significant impact on sexual behavior.
  • Regulation of Energy and Appetite: Both MC3R and MC4R are integral to managing energy balance and appetite. Activation of MC4R in particular is associated with reduced appetite and potential weight loss.

PT-141 shows a higher affinity for MC4R than MC1R and MC3R. MC4R is found in the brain (namely in the medial preoptic area) and is crucial for regulating sexual behavior, energy, and appetite.

By activating MC4R, PT-141 is able to stimulate brain pathways related to sexual arousal and motivation, having been shown to enhance sexual desire and improve sexual performance [3].

Additionally, PT-141 may maintain some affinity for MC1R in the skin, promoting melanin synthesis and contributing to skin pigmentation when administered too frequently and at high doses [4].

pt-141 nasal spray

What is PT-141 Used For?

PT-141 has been extensively tested for its ability to activate the MC4R and stimulate sexual function in both men and women.

  • In women, numerous phase 2b and phase 3 trials have tested the potential of PT-141 in the management of hypoactive sexual desire disorder (HSDD) and female sexual arousal disorder (FSAD). Their successful outcomes have led to the official approval of PT-141 as subcutaneous injections by the Food and Drug Administration (FDA) for HSDD management in premenopausal women and is marketed under the brand name Vyleesi ) [5].
  • In addition, PT-141 has also been tested in men, particularly in the form of intranasal spray, and the available studies suggest that the peptide is also highly effective for improving sexual desire and erectile function in males [6].

PT-141 is thought to increase sexual desire in both men and women by activating the MC4R in the brain, which ultimately leads to an increase in the production of neurotransmitters like dopamine in specific brain areas related to libido and sex drive [7].

Thus, PT-141 may boost sexual desire, intensify arousal, and elevate sexual pleasure. However, it is crucial to understand that this compound does not tackle other potential contributors of sexual dysfunction, including physical or relational factors.

The available clinical data on PT-141 in women reports that the peptide effectively increases sex drive and desire within 45 minutes of subcutaneous administration. Therefore, the peptide is meant to be used on demand, and the effects last for about 2-4 hours once administered [8].

PT-141 could also potentially decrease hunger via its stimulation of MC4R, thus aiding in energy consumption reduction and promoting weight loss. Ongoing phase 1 clinical trials are exploring PT-141's effectiveness in this area.

For example, a study in 27 obese women receiving PT-141 showed a decrease in daily calorie intake by 400kcals and an average weight loss of 3.7lb over 16 days, surpassing the 2lb loss observed in the placebo group [9].

PT-141 Nasal Spray Reviews | What Researchers MUST Know

The available scientific literature comprises numerous studies investigating the efficacy of PT-141 in nasal spray spray format [10].

Here are some of the most notable findings related to intranasal PT-141 to date:

  • Safarinejad et al. (2008) sought to test PT-141 in men with erectile dysfunction (ED) who did not otherwise respond to sildenafil (Viagra). PT-141 given as an intranasal dose of 10mg 45-120 minutes before sexual interaction led to positive effects in 33.5% of the patients, compared with 8.5% of the patients in the placebo group [6].
  • In a Phase IIb study by Steidle et al. (2007), 294 diabetics with ED were randomized to receive either placebo or one of three doses of PT-141 (10mg, 12.5mg, or 15mg) for 12 weeks, attempting intercourse at least twice weekly. The PT-141 12.5mg and 15mg groups had significantly improved erectile function compared to placebo [11].
  • Diamond et al. (2005) conducted a study in 19 men with ED who previously responded to sildenafil. The researchers administered either a combination of sildenafil 25mg and intranasal PT-141 7.5mg, sildenafil and placebo, or double placebo in a randomized cross-over design. The erectile response in the PT-141/sildenafil combination group was significantly better than for sildenafil alone [12].
  • Lastly, Diamond et al. (2004) tested PT-141 in both healthy and Viagra-responsive ED patients, with and without visual sexual stimulation. PT-141 showed dose-dependent increases in concentration and exposure, with statistically significant erectile responses at doses from 7mg, usually starting 30 minutes after administration [13].

Overall, studies on PT-141 nasal spray report that the peptide has a potent erectogenic effect, with many researchers suggesting that it may be a candidate for therapy in males with ED [14].

PT-141 Nasal Spray vs. Injections | A Comprehensive Comparison

When comparing PT-141 nasal spray vs. injections, researchers should consider factors like the bioavailability, ease of use, and potential adverse reactions associated with both formats. Based on these factors, here is a brief comparison between the two routes of administration:

  • Bioavailability: Overall, researchers should expect significantly higher bioavailability with PT-141 injections compared to PT-141 nasal spray. According to the available data, subcutaneous PT-141 doses of as little as 1mg have been found effective at improving erectile function in ED patients. By comparison, PT-141 nasal spray has been administered at doses starting from 7mg for the treatment of ED [10, 15].
  • Ease of use: PT-141 nasal spray is considerably easier to use and administer, as it can be conveniently sprayed in the nostrils. By comparison, PT-141 powder for injection should first be reconstituted and then administered subcutaneously while following standard safety procedures.
  • Side effects: PT-141 injections can produce adverse reactions at the injection site, which may include mild, transitory redness, pain, swelling, or induration. Otherwise, PT-141 in either format may produce side effects like nausea, sweating, or facial flushing [16].

PT-141 Nasal Spray Dosage | Research Only

According to the available scientific data, PT-141 nasal spray has been shown to improve erectile function in men when administered at starting doses of 7mg. PT-141 is designed to be administered on-demand, within 30 minutes prior to sexual activity [13].

Moreover, the peptide has been tested in intranasal doses of up to 15mg, with researchers suggesting favorable safety and effectiveness when administered no more than twice weekly for 12 weeks [11].

However, researchers may consider starting at a significantly lower dose of intranasal PT-141, and titrating up based on the subject’s response and tolerability.

In general, PT-141 should not be administered more than twice weekly or eight times monthly, since overly frequent administration can increase the risk of side effects such as skin darkening.

How to Make PT-141 Nasal Spray

PT-141 for injection typically comes in the form of lyophilized powder that requires reconstitution before use. By contrast, a PT-141 nasal spray product will typically arrive pre-mixed with a solvent and suitable preservatives and pre-filled into a spray bottle.

Therefore, researchers do not have to calculate the required amount of solvent to manually reconstitute the peptide into liquid form.

Nevertheless, a PT-141 nasal spray should always be lept refrigerated when not in use at temperatures between 36-46 F. Moreover, the nozzle of the spray must be disinfected with an alcohol swab before and after each use.

The spray bottle must not be shaken or taped forcefully, as this can degrade the peptide and render it ineffective. Direct sunlight, heating, or freezing of the peptide may also damage its structure.

Side Effects of PT-141 Nasal Spray

PT-141 is generally well-tolerated when applied to enhance sexual desire in women or improve erectile function in men. The primary safety consideration with PT-141 is that it should not be administered to subjects with unmanaged high blood pressure or cardiovascular conditions [17].

This caution is due to the potential of PT-141 to cause temporary rises in blood pressure. This effect is particularly noted with nasal spray use, which may be due to the higher dosages needed compared to subcutaneous injections [16].

In a study spanning 16 weeks and including 172 male participants, the following side effects were observed following at least 16 doses (limited to one per day and a maximum of eight per month) [6]:

  • Nausea: 12.8%
  • Facial Flushing: 10.5%
  • Increased Sweating: 9.3%
  • Taste Disturbances: 4.7%

These effects, particularly changes in taste, are common with peptide nasal sprays and are associated with the method of delivery.

Additional mild and temporary side effects linked to intranasal application include irritation of the nose or throat, sneezing, and coughing.

pt-141 nasal spray

Where to Buy PT-141 Nasal Spray Online? | 2024 Edition

There are a number of PT-141 nasal spray products on the market, with expert reviewers reporting a range of experiences with their purchases.

To help researchers find the best PT-141 nasal spray for their needs, our team has tested products from the top online peptide vendors.

We looked at factors like peptide quality, payment and shipping policies, and customer service to identify our top pick.

Here it is:

Limitless Life

Based on our survey, Limitless Life has the best PT-141 nasal spray on the market, available in a convenient 50mg spray bottle.

Limitless Life stands apart from other vendors for the following reasons:

  • Lab-Tested Products: Limitless Life submits all of its compounds to rigorous third-party lab testing to ensure the highest quality and purity standards. Each product comes with a certificate of analysis for added peace of mind.
  • Convenient Payments: Limitless Life accepts a range of convenient and secure payments, including major credit cards, bank transfer, and cryptocurrencies. The vendor currently offers a discount on all orders not paid by credit card.
  • Reliable Shipping: The vendor ships all orders using priority mail to ensure that products arrive to customers as quickly as possible. Shipping fees on all orders of $350+ are waived.
  • Customer Service: Researchers can contact the Limitless Life customer service team via phone or email, and expect quick resolution of any issues.

Researchers looking to buy high-quality PT-141 nasal spray for their next study are advised to check out Limitless Life, a trusted name in the research chemicals industry.

Furthermore, researchers should be aware that the PT-141 nasal spray from Limitless Life is the only one on the market with enough PT-141 to see true results from a study. While their product may be more costly, there is good reason for that.

In addition…

Any and all qualified researchers may get 10% off their order with Limitless Life by clicking the button below, then adding the code:


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PT-141 Injections vs. Nasal Spray | Verdict

PT-141 has significant therapeutic potential that is backed by extensive clinical research highlighting its ability to safely and effectively treat sexual dysfunction.

The synthetic alpha-MSH analog targets and activates melanocortin receptor 4, a potent mediator of sexual function in both men and women.

The peptide is available in a convenient nasal spray format, having been shown to deliver effects in as little as 30 minutes. It may also be administered as a subcutaneous injection, which typically works within 45 minutes.

Both formats have their advantages and disadvantages, and researchers must carefully consider factors like bioavailability, ease of use, and cost before selecting their preferred formulation for laboratory experiments.

Qualified professionals looking for research-grade PT-141 nasal spray are encouraged to head over to our most trusted vendor of research peptides.


  1. Sauter, M., Uhl, P., Burhenne, J., & Haefeli, W. E. (2020). Ultra-sensitive quantification of the therapeutic cyclic peptide bremelanotide utilizing UHPLC-MS/MS for evaluation of its oral plasma pharmacokinetics. Journal of pharmaceutical and biomedical analysis, 186, 113276.
  2. Yeo, G. S. H., Chao, D. H. M., Siegert, A. M., Koerperich, Z. M., Ericson, M. D., Simonds, S. E., Larson, C. M., Luquet, S., Clarke, I., Sharma, S., Clément, K., Cowley, M. A., Haskell-Luevano, C., Van Der Ploeg, L., & Adan, R. A. H. (2021). The melanocortin pathway and energy homeostasis: From discovery to obesity therapy. Molecular metabolism, 48, 101206.
  3. King, S. H., Mayorov, A. V., Balse-Srinivasan, P., Hruby, V. J., Vanderah, T. W., & Wessells, H. (2007). Melanocortin receptors, melanotropic peptides and penile erection. Current topics in medicinal chemistry, 7(11), 1098–1106.
  4. Mun, Y., Kim, W., & Shin, D. (2023). Melanocortin 1 Receptor (MC1R): Pharmacological and Therapeutic Aspects. International journal of molecular sciences, 24(15), 12152.
  5. Edinoff, A. N., Sanders, N. M., Lewis, K. B., Apgar, T. L., Cornett, E. M., Kaye, A. M., & Kaye, A. D. (2022). Bremelanotide for Treatment of Female Hypoactive Sexual Desire. Neurology international, 14(1), 75–88.
  6. Safarinejad, M. R., & Hosseini, S. Y. (2008). Salvage of sildenafil failures with bremelanotide: a randomized, double-blind, placebo controlled study. The Journal of urology, 179(3), 1066–1071.
  7. Pfaus, J. G., Sadiq, A., Spana, C., & Clayton, A. H. (2022). The neurobiology of bremelanotide for the treatment of hypoactive sexual desire disorder in premenopausal women. CNS spectrums, 27(3), 281–289.
  8. Mayer, D., & Lynch, S. E. (2020). Bremelanotide: New Drug Approved for Treating Hypoactive Sexual Desire Disorder. The Annals of pharmacotherapy, 54(7), 684–690.
  9. Spana, C., Jordan, R., & Fischkoff, S. (2022). Effect of bremelanotide on body weight of obese women: Data from two phase 1 randomized controlled trials. Diabetes, obesity & metabolism, 24(6), 1084–1093.
  10. Hellstrom W. J. (2008). Clinical applications of centrally acting agents in male sexual dysfunction. International journal of impotence research, 20 Suppl 1, S17–S23.
  11. Kaminetsky, J., Zinner, N. R., Gittleman, M., Auerbach, S., & Fischkoff, S. (2007). 1042: phase IIB study of bremelanotide in the treatment of ED in non-diabetic males. The Journal of Urology, 177(4S), 345-345.
  12. Diamond, L. E., Earle, D. C., Garcia, W. D., & Spana, C. (2005). Co-administration of low doses of intranasal PT-141, a melanocortin receptor agonist, and sildenafil to men with erectile dysfunction results in an enhanced erectile response. Urology, 65(4), 755–759.
  13. Diamond, L. E., Earle, D. C., Rosen, R. C., Willett, M. S., & Molinoff, P. B. (2004). Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141, a melanocortin receptor agonist, in healthy males and patients with mild-to-moderate erectile dysfunction. International journal of impotence research, 16(1), 51–59.
  14. Kim, S., Cho, M. C., Cho, S. Y., Chung, H., & Rajasekaran, M. R. (2021). Novel Emerging Therapies for Erectile Dysfunction. The world journal of men's health, 39(1), 48–64.
  15. Rosen, R. C., Diamond, L. E., Earle, D. C., Shadiack, A. M., & Molinoff, P. B. (2004). Evaluation of the safety, pharmacokinetics and pharmacodynamic effects of subcutaneously administered PT-141, a melanocortin receptor agonist, in healthy male subjects and in patients with an inadequate response to Viagra. International journal of impotence research, 16(2), 135–142.
  16. Reddy, M. S., & Vijay, M. S. (2017). Pharmacological Advances in the Management of Sexual Dysfunction. Indian journal of psychological medicine, 39(3), 219–222.
  17. Vyleesi Injection: Package insert. (n.d.).

Scientifically Fact Checked by:

David Warmflash, M.D.

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