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A-F grade per outcome, combining overall evidence with goal-specific relevance. A = strong evidence; F = insufficient. Hover a badge for details.
Topical only. OTC cosmetic azelaic acid is typically around 10%; prescription strengths are 15% gel/foam (rosacea) and 20% cream (acne), applied as a thin layer to clean skin once or twice daily. There is no oral, injectable, or systemic dose. For rosacea or persistent acne, the prescription form under a clinician is the evidence-based route. This library does not provide an ingestion protocol.
Any time
Leave-on topical gel, foam, or cream (OTC ~10%, or prescription 15-20%)
Prescription topical. Hydroquinone is used at 2-4% (often as the triple-combination with a retinoid and a mild corticosteroid), applied to pigmented areas usually at night, in time-limited courses (commonly with treatment breaks) under clinician supervision, always with daily sunscreen. There is no oral or systemic use. Avoid indefinite continuous use because of ochronosis risk. This library does not provide an ingestion protocol.
Evening
Hydroquinone 2-4% cream or the triple-combination (with retinoid + mild steroid), under a clinician
Throughout
4-15 weeks
8-24 weeks
Throughout
8-12 weeks
Throughout
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