Can peptides cause skin changes like rashes or hyperpigmentation?

Melanotan peptides intentionally darken skin, but other peptides rarely cause pigmentation changes. Injection site reactions (redness, itching) are common and usually benign. Widespread rash or hives suggests allergic reaction—discontinue and seek medical care. <a href='https://www.aad.org/public/diseases/a-z/hives-overview' target='_blank'>AAD Hives Overview</a>