Does PT-141 cause tanning?

Minimal. PT-141 does not significantly activate MC1R (the primary tanning receptor) at standard doses (1.75mg). Melanotan II strongly activates MC1R at equivalent doses, producing dose-dependent skin darkening.

Is PT-141 FDA approved?

Yes. Bremelanotide (Vyleesi) was FDA-approved in June 2019 for hypoactive sexual desire disorder (HSDD) in premenopausal women. It is the first and only FDA-approved on-demand treatment for female sexual dysfunction.

PT-141 vs Melanotan II: Dosing, Half-Life, Side Effects + Which to Choose (2026) | PeptiDex

Quick Verdict

PT-141 (Bremelanotide) for sexual dysfunction — FDA-approved for female HSDD with strong libido enhancement evidence. Melanotan II for tanning with libido as a secondary effect. PT-141 is the significantly safer and more targeted choice for sexual health research.

Side-by-Side Analysis

Dimension	PT-141	Melanotan II
Mechanism	Central melanocortin pathway.	MC4R activation.
Primary Benefits	Sexual arousal, libido	Tanning, libido enhancement
Typical Dose	1500–1500mcg	250–250mcg
Route	SubQ	SubQ
Frequency	2x/wk	7x/wk
Half-Life	2.7 hours	1 hours
FDA Status	Approved	Research Only
Evidence Grade	very-strong	moderate
Key Studies	19+ indexed	20+ indexed
Lowest Price	$45.00 / 10mg via Ascension Peptides	$40.00 / 10mg via Ascension Peptides

Which one should you choose?

PT-141 is strictly for enhancing libido and sexual function, while Melanotan II (MT2) is primarily for skin tanning with libido enhancement as a side effect. PT-141 is actually a synthetic derivative of MT2 that was isolated specifically for its strong aphrodisiac effects via the melanocortin receptors in the brain, without causing significant skin pigmentation. MT2 strongly stimulates melanin production while also providing some arousal effects. Choose PT-141 (an FDA-approved formulation) if your sole goal is treating sexual dysfunction in men or women. Choose MT2 if your primary goal is tanning. PT-141 is the much safer default for sexual health.

Who Should Choose PT-141?

Choose PT-141 if you:

Are specifically researching sexual dysfunction in men or women
Want the FDA-approved melanocortin agonist with the cleanest libido profile
Need enhanced sexual desire without significant skin pigmentation
Are researching female hypoactive sexual desire disorder (HSDD)

Who Should Choose Melanotan II?

Choose Melanotan II if you:

Are specifically researching skin tanning and melanin stimulation
Want concurrent tanning and libido enhancement effects
Are studying broader melanocortin receptor pharmacology (MC1R-MC5R)
Accept higher side effect risk (nausea, spontaneous erections, mole darkening) as part of the research context

Can you stack PT-141 + Melanotan II?

Do NOT combine PT-141 and Melanotan II. Both act on the same melanocortin receptors (MC3R, MC4R). Combining them creates additive receptor saturation with compounded side effects: severe nausea, prolonged erections, and cardiovascular stress. Use one at a time.

Vendor Pricing

· Affiliate links · Prices verified 2026

PT-141

2 vendors

Ascension Peptides Best Value

10mg vial · $4.50/mg

$45.00Buy

Bio Longevity LabsTriple-Tested

5mg vial · $9.59/mg

$47.97Buy

Full vendor comparison for PT-141

Melanotan II

2 vendors

Ascension PeptidesBest Price Best Value

10mg vial · $4.00/mg

$40.00Buy

Bio Longevity LabsTriple-Tested

10mg vial · $5.60/mg

$55.97Buy

Full vendor comparison for Melanotan II

Affiliate disclosure: PeptiDex may earn a commission from purchases via vendor links at no extra cost to you. See our methodology.

Frequently Asked Questions

PT-141 (Bremelanotide) is a direct derivative of Melanotan II with one key modification: a hydroxyl group replacing the amino terminus. This change dramatically reduces melanin stimulation while preserving the MC4R-mediated libido effects. PT-141 is selective for sexual function; MT2 is broader.

Deep Dive Profiles

PT-141 Research Profile Melanotan II Research Profile

Research Tools

PK Plasma Curves

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Reconstitution Calculator

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Research Use Only — Not Medical Advice

This comparison is provided for educational and research purposes only. It does not constitute medical, prescribing, or treatment advice. Clinical data cited here is sourced from published peer-reviewed trials and FDA labels. Consult a qualified healthcare professional before making any decisions about medications or research compounds. PeptiDex is an informational resource and does not sell pharmaceutical products.