vitamin-c-serums
Guava Vitamin C Dark Spot Serum
While the airless pump packaging is excellent for stability, the formula uses a 10% 'complex' of Vitamin C derivatives rather than the gold-standard pure L-Ascorbic Acid. It is a stable, low-irritation option suitable for sensitive skin, but it contains added fragrance and lacks the specific pH-dependent penetration data of the Duke Parameters.
Sources & References
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CeraVe
Hydrating Facial Cleanser
Contains ceramides and hyaluronic acid. Gentle, non-stripping, maintains skin barrier. Dermatologist-developed and recommended.
Differin
Adapalene Gel 0.1%
Only prescription-strength retinoid available OTC. FDA-approved for acne. Less irritating than tretinoin. Direct retinoic acid receptor binding—no conversion needed.
EltaMD
UV Clear Broad-Spectrum SPF 46
Widely considered the gold standard for sensitive and acne-prone skin, utilizing high-purity transparent zinc oxide combined with niacinamide to calm inflammation. It is one of the few sunscreens that consistently maintains a high-performance profile without triggering breakouts or leaving a heavy residue.
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Anthelios Melt-in Milk Sunscreen SPF 60
This product consistently achieves perfect scores in independent lab testing for actual SPF delivery versus labeled SPF. Its Cell-Ox Shield technology provides a potent antioxidant complex that mitigates free radical damage beyond just UV filtration.