Skincare breakthrough? new study tests niacinamide creams for dark spots in black women

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Female participants aged 18 to 55 years * Clinical diagnosis of facial post-inflammatory hyperpigmentation (PIH) * Self-identified as Black (including "preta" or "parda") * Fitzpatrick skin types IV to VI * Employees, students, or affiliated personnel of Hospital Israelita Albert Einstein (including contractors and fellows), recruited from institution units * Willing and able to comply with all study procedures and attend all scheduled visits * Able and willing to provide written informed consent and authorization for image use Exclusion Criteria: * Pregnant or breastfeeding women, or those planning pregnancy during the study period * Type 1 diabetes mellitus or related complications (e.g., nephropathy, dermatological conditions associated with diabetes, history of hypoglycemia, diabetic ketoacidosis, or hyperosmolar coma) * Known or suspected intolerance to similar cosmetic products * History of atopy or allergic reactions to cosmetic products * Personal or family history of skin cancer * Active skin conditions or lesions affecting the face * Facial marks or scars that may interfere with assessments * Skin irritation due to recent sun exposure * Excessive sun or UV exposure, including artificial tanning, within the past month * Use of facial cosmetic products within 7 days before screening * Use of topical or systemic treatments within 1 month before screening * Use of depigmentation treatments within 3 months before screening * Use of dermocosmetic treatments for PIH within 3 months before screening * Facial dermatological or aesthetic procedures within 2 weeks before screening * Use of corticosteroids, anticoagulants, or immunosuppressive drugs * Score ≥5 indicating anxiety or depression on Patient Health Questionnaire (PHQ-9) or Generalized Anxiety Disorder scale (GAD-7) * Any other condition that, in the investigator's judgment, may compromise study participation or results (to be documented in the medical record)