Compare Supplements

Topical cosmetic only. OTC retinol is formulated roughly 0.1-1% in leave-on serums or creams and applied to clean, dry facial skin at night, starting 2-3 nights per week and building to nightly as tolerated. There is no oral, injectable, or systemic dose — this is not ingested. Higher concentrations work somewhat better but irritate more; pair with a moisturizer and a morning sunscreen. This library does not provide an ingestion protocol.

Evening

Leave-on topical serum or cream (0.1-1% retinol)

Topical cosmetic only. L-ascorbic acid serums are typically 10-20% (often near pH 3 for absorption); stable derivatives are used at varying percentages. Apply a few drops to clean, dry skin, usually in the morning under sunscreen (its antioxidant action complements SPF). There is no oral, injectable, or systemic dose in this cosmetic context. This library does not provide an ingestion protocol.

Morning

Leave-on topical serum (10-20% L-ascorbic acid) or a stable vitamin C derivative

• For topical (skin) use only — not for ingestion, not for injection
• Pregnancy and breastfeeding — generally advised to avoid topical retinoids as a precaution
• Active eczema, rosacea flares, or broken/irritated/sunburned skin until healed

• Strong leave-on exfoliating actives (AHAs/BHAs, benzoyl peroxide)
• Other retinoids (prescription tretinoin, tazarotene, adapalene)

• For topical (skin) use only — not for ingestion, not for injection (in this cosmetic context)
• Known allergy or sensitivity to the formulation
• Application to broken, irritated, or compromised skin until healed

• Strong leave-on actives (retinoids, AHAs/BHAs, benzoyl peroxide)
• Niacinamide