PeptidesEvidence ReviewAug 2026

Best Peptides for Libido and Erectile Dysfunction in 2026

For each peptide studied for libido and erectile dysfunction, this page reports the trials behind it: who was enrolled, what was measured, what the paper found. Every citation was retrieved through NCBI E-utilities on 9 August 2026. Low sexual desire and erectile dysfunction are medical conditions that a doctor diagnoses and manages, and erectile dysfunction in particular can be an early marker of cardiovascular or hormonal disease. The population column is where each result is pinned to the men or women it came from, not read as advice.

1,267

Women in the bremelanotide phase 3 trials (PMID 31599840)

Men who completed the kisspeptin HSDD trial (PMID 36735255)

Women who completed the kisspeptin HSDD trial (PMID 36287566)

The Studies

One row per study, not one per compound. A compound tested more than once gets more than one row, because those papers asked different questions in different populations. Read the population and design columns before the result. A brief note on the pt141 and kisspeptin molecules sits on their own pages so this table can stay about the trials.

Compound	Population (n)	What was measured	Result	Design	PMID
Bremelanotide (PT-141), subcutaneous	1,267 premenopausal women with hypoactive sexual desire disorder across two identical trials (RECONNECT, studies 301 and 302)	Change in the Female Sexual Function Index desire domain and Female Sexual Distress Scale item 13 over 24 weeks	Desire rose (integrated 0.35, P below .001) and distress about low desire fell (integrated -0.33, P below .001) versus placebo; nausea, flushing and headache each affected 10 percent or more	Two randomised double-blind placebo-controlled phase 3 trials	31599840
Bremelanotide (PT-141), subcutaneous	397 premenopausal women with female sexual dysfunction, normotensive or with controlled hypertension	Ambulatory systolic and diastolic blood pressure and heart rate after dosing	Systolic pressure rose 3.1 to 3.2 mmHg versus placebo at the 1.75 mg dose (P = .006 and .027), peaks usually under 15 minutes, alongside a fall in heart rate; 26 participants discontinued for prespecified pressure rises, similar across arms	Randomised double-blind placebo-controlled parallel-arm trial	27977473
Kisspeptin-54, intravenous infusion	32 heterosexual men with hypoactive sexual desire disorder who completed the trial (37 randomised), mean age 38	Whole-brain fMRI response to sexual videos, penile tumescence, and behavioural desire measures	Modulated sexual-processing brain activity versus placebo (Cohen d 0.81, 95 percent CI 0.41 to 1.21, P = .003); penile tumescence up to 56 percent higher (P = .02); happiness about sex increased (P = .02)	Double-blind two-way crossover placebo-controlled randomised trial	36735255
Kisspeptin-54, intravenous infusion	32 premenopausal women with hypoactive sexual desire disorder who completed the trial (40 randomised), mean age 29	Blood oxygen level-dependent fMRI response to erotic videos and to faces of varying attractiveness	Modulated sexual and attraction brain processing versus placebo (right postcentral and supramarginal activation Z max 3.73, P below .001); hippocampal activity correlated with baseline sexual distress (r = 0.469, P = .007); no adverse effects reported	Double-masked two-way crossover placebo-controlled randomised trial	36287566
PT-141 (bremelanotide), subcutaneous	Healthy men, and men with erectile dysfunction reporting inadequate response to sildenafil (n not stated in the abstract)	RigiScan erectile response (healthy men without visual sexual stimulation; patients with it)	Erectile response reached significance at subcutaneous doses above 1.0 mg in healthy men and at 4 and 6 mg in the patients versus placebo; safe and well tolerated	Dose-ranging study plus a placebo-controlled crossover	14999221
PT-141 (bremelanotide) intranasal, with sildenafil	19 men with erectile dysfunction who responded to sildenafil or vardenafil by self-report	RigiScan erectile response to visual sexual stimulation over 6 hours	Erectile response to intranasal PT-141 plus low-dose sildenafil was greater than sildenafil alone; well tolerated with no new adverse events	Randomised crossover	15833522
Melanotan-II, subcutaneous	10 men with psychogenic erectile dysfunction of no known organic cause	RigiScan tip rigidity and erection duration over 6 hours	Clinically apparent erections in 8 of 10; mean duration of tip rigidity above 80 percent was 38.0 minutes versus 3.0 on placebo (P = .0045); transient nausea, yawning and reduced appetite	Double-blind placebo-controlled crossover	9679884
Melanotan-II, subcutaneous	10 men with erectile dysfunction and organic risk factors	RigiScan tip rigidity, erection duration and self-reported sexual desire over 6 hours	Subjective erections in 12 of 19 injections versus 1 of 21 placebo doses; tip rigidity above 80 percent 45.3 versus 1.9 minutes (P = .047); higher self-reported desire; severe nausea in 4 of 19 injections	Double-blind placebo-controlled crossover	11018622

Trials In Women

The women's trials enrolled premenopausal women with hypoactive sexual desire disorder. In the RECONNECT program, two identical phase 3 trials randomised 1,267 women to as-needed subcutaneous bremelanotide or placebo for 24 weeks, and reported a rise in the Female Sexual Function Index desire domain and a fall in desire-related distress, both statistically significant against placebo, with nausea, flushing and headache the common side effects (PMID 31599840). A separate ambulatory study of 397 women measured what the melanocortin-4 receptor mechanism does to blood pressure, finding small transient rises after dosing with a matching fall in heart rate (PMID 27977473). That safety signal is why the phase 3 protocol built in blood-pressure monitoring.

A different mechanism was tested in the kisspeptin work. In 32 premenopausal women with the same diagnosis, an intravenous kisspeptin-54 infusion modulated sexual and facial-attraction brain processing on fMRI, and the enhancement of hippocampal activity in response to erotic videos correlated with each woman's baseline sexual distress (PMID 36287566). It measured brain response, not a treatment course. The broader hormonal picture behind female desire sits on the hormones guide.

Trials In Men

The male trials split between desire and erection. On desire, 32 men with hypoactive sexual desire disorder received intravenous kisspeptin-54 or placebo in a crossover, and kisspeptin modulated activity across the sexual-processing brain network while raising penile tumescence in response to sexual videos by up to 56 percent over placebo, alongside a reported increase in happiness about sex (PMID 36735255). On erection, the melanocortin agonist PT-141 produced a significant RigiScan erectile response in men with an inadequate response to sildenafil at 4 and 6 mg subcutaneous (PMID 14999221), and intranasal PT-141 combined with a low dose of sildenafil produced a greater erectile response than sildenafil alone in 19 men (PMID 15833522). Background on the compound sits on the PT-141 page, and a wider survey of men's options on the best peptides for men guide.

Melanotan-II, the alpha-melanocyte-stimulating hormone analogue that the PT-141 chemistry descends from, was tested earlier in two small crossover studies. In 10 men with psychogenic erectile dysfunction it produced clinically apparent erections in 8, with tip rigidity above 80 percent lasting 38 minutes against 3 on placebo (PMID 9679884), and in 10 men with organic risk factors it produced subjective erections in 12 of 19 injections and raised self-reported desire, though severe nausea occurred in 4 of 19 injections (PMID 11018622). Those tolerability figures matter. The melanotan-2 and melanotan-1 pages carry the compound background.

The Trial Regimens

The regimens these trials administered, each named with its paper:

Bremelanotide 1.75 mg subcutaneous, taken as needed over 24 weeks, in the phase 3 women (PMID 31599840). PT-141 4 to 6 mg subcutaneous, and 7.5 mg intranasal with sildenafil 25 mg, in the erectile dysfunction studies (PMID 14999221, PMID 15833522). Kisspeptin-54 by intravenous infusion at 1 nmol/kg/h for 75 minutes in the desire trials (PMID 36735255, PMID 36287566). Melanotan-II 0.025 mg/kg subcutaneous in the erectile dysfunction studies (PMID 9679884, PMID 11018622).

Disclaimer: these are trial arms reported for comparison, not recommendations and not a titration schedule. Each was administered under medical supervision inside its study, and injectable use is a clinical decision. How injections are handled is covered on the COA verification guide, which is about knowing what is in a vial before anything else.

A Note On Approval

The United States Food and Drug Administration approved bremelanotide, marketed as Vyleesi, in June 2019 for acquired, generalised hypoactive sexual desire disorder in premenopausal women, administered as an as-needed subcutaneous injection (source: US Food and Drug Administration). That decision names a jurisdiction, a population and an indication, and it does not extend to erectile dysfunction in men. What any regulator has decided about a given compound, in a given country, is a question for a clinician and the relevant agency, not something to infer from a trial result.

How These Records Were Found

Each line states a query, an index and a date. A search result describes what a string matched in one database on one day, nothing beyond that.

bremelanotide AND hypoactive sexual desire in PubMed on 9 August 2026 returned 51 records, among them the phase 3 RECONNECT report PMID 31599840.
bremelanotide AND erectile in PubMed on 9 August 2026 returned 16 records; PT-141 AND sexual returned 91.
kisspeptin AND hypoactive sexual desire in PubMed on 9 August 2026 returned 4 records, including the men and women trials PMID 36735255 and PMID 36287566.
melanotan II AND erectile in PubMed on 9 August 2026 returned 23 records; the two double-blind crossover trials read here were PMID 9679884 and PMID 11018622.
Wessells AND melanotan in PubMed on 9 August 2026 returned 3 records, which located the melanotan-II erectile studies above.
A compound name bounds a search, so synonyms and MeSH entry terms were tried: PT-141 as bremelanotide, melanotan as melanotan-II and alpha-melanocyte-stimulating hormone analogue, and kisspeptin as kisspeptin-54.

Frequently Asked Questions

What are the best peptides for libido and erectile dysfunction?+

This page does not rank them. It reports what each cited trial enrolled, what it measured and what it found, so a 1,267-woman phase 3 desire trial and a 10-man erection study can be told apart. Read the population and design columns before the result, because the desire trials in premenopausal women and the erection trials in a handful of men measured different outcomes in different people.

Is erectile dysfunction something to treat on my own with a peptide?+

No. Erectile dysfunction and persistent low desire are medical conditions that are diagnosed and managed with a doctor, and erectile dysfunction can be an early sign of cardiovascular or hormonal disease that needs its own workup. Every regimen in the table was administered inside a trial under medical supervision. Take the population and the endpoint to a clinician rather than a compound name off a label.

What did the kisspeptin trials actually measure?+

Mostly the brain. In 32 men with hypoactive sexual desire disorder, an intravenous kisspeptin-54 infusion modulated activity across the sexual-processing network on fMRI and raised penile tumescence in response to sexual videos (PMID 36735255). In 32 women with the same diagnosis, it modulated sexual and facial-attraction brain processing, and the change in hippocampal activity tracked how much distress each woman reported at baseline (PMID 36287566). These are mechanism and imaging studies, not long treatment courses.

Does a result in women with low desire apply to a man with erectile dysfunction?+

Not automatically. The RECONNECT trials enrolled premenopausal women with hypoactive sexual desire disorder and measured desire and distress questionnaires (PMID 31599840); the melanotan-II and PT-141 erectile studies enrolled men and measured RigiScan rigidity (PMID 9679884, PMID 14999221). Different populations, different endpoints. Each number applies to the people its trial enrolled and reads across to anyone else only through further study.

What side effects did these trials report?+

The melanocortin compounds share a tolerability signal. In the phase 3 women, bremelanotide caused nausea, flushing and headache in 10 percent or more (PMID 31599840), and a separate ambulatory study measured small transient rises in blood pressure with a fall in heart rate after dosing (PMID 27977473). The melanotan-II erectile studies reported nausea, yawning and reduced appetite, with severe nausea in 4 of 19 injections in one trial (PMID 11018622). The kisspeptin infusions reported no adverse effects in their write-ups.

How was each compound given in the trials?+

By injection or infusion, not by mouth. Bremelanotide was a 1.75 mg subcutaneous dose taken as needed in the phase 3 women (PMID 31599840); PT-141 was 4 to 6 mg subcutaneous or 7.5 mg intranasal in the erectile studies (PMID 14999221, PMID 15833522); kisspeptin-54 was an intravenous infusion at 1 nmol/kg/h for 75 minutes (PMID 36735255); melanotan-II was 0.025 mg/kg subcutaneous (PMID 9679884). Disclaimer: these are per-trial figures reported for comparison, not recommendations and not a titration schedule; the full regimens sit with their disclaimer in the trial regimens section.

Research And Sources

Every figure above comes from the record its PMID links to, retrieved through NCBI E-utilities on 9 August 2026. The desire and distress changes come from PMID 31599840, the blood-pressure figures from PMID 27977473, the men's brain and tumescence results from PMID 36735255, the women's brain results from PMID 36287566, the PT-141 erectile figures from PMID 14999221 and PMID 15833522, and the melanotan-II figures from PMID 9679884 and PMID 11018622. The provenance section records what each search returned rather than the body claiming anything about what does or does not exist.