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What to Expect

Will PT-141 darken my skin or freckles?

Updated 2026-05-05

Yes, PT-141 can cause focal hyperpigmentation - dark patches on the face, gums, or breasts - especially with frequent use. This is because PT-141 acts on melanocortin receptors that also control skin pigment cells. In the Vyleesi trials, about 1% of patients had this side effect on the typical labeled schedule. The risk goes up with more than 8 doses per month. New darker freckles or blotchy spots may fade after stopping but are not guaranteed to fully reverse.

IfIf you notice new dark patches on your face, gums, or chest
Thenthen pause PT-141 and check in with a doctor - it can fade but is not guaranteed to
IfIf you have darker skin tone or a history of melasma
Thenthen your risk of hyperpigmentation is higher; start at the lowest possible dose
IfIf you stop PT-141 and pigmentation does not fade in 6-12 months
Thenthen ask a dermatologist about treatments like topical retinoids or hydroquinone
IfIf you are dosing more than 8 times a month
Thenthen cut back - frequency is the strongest driver of pigment changes
Key facts
  • PT-141 binds the melanocortin-1 receptor (MC1R), which is the same receptor that triggers melanin production
  • About 1% of phase 3 patients on the labeled schedule developed focal hyperpigmentation
  • Risk is higher in people with darker baseline skin tone and in those who exceed 8 doses/month
  • Pigmentation changes are typically focal (face, gums, breasts) rather than total-body tanning
  • Reversibility is variable - some fade after stopping, some do not
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