RECEIPT ENGINE · VERSION 0.1
This is the small, public source library used by the checker. A grade describes context for common claims—not the quality or safety of every product containing the ingredient.
Deficiency can affect hair and skin, but deficiency is rare and evidence for high-dose supplements in otherwise healthy people is limited. High doses can interfere with some laboratory tests.
NIH Office of Dietary Supplements source ↗Some trials report modest changes in skin hydration or elasticity, while formulations, doses and study quality vary. Ingredient evidence is not a finished-product trial.
Harvard Nutrition Source ↗Vitamin C has established roles in collagen synthesis and antioxidant function. That does not mean extra intake always creates a visible beauty result.
NIH Office of Dietary Supplements source ↗Zinc is essential and involved in immune function and wound healing. Long-term high intakes can cause problems including copper deficiency.
NIH Office of Dietary Supplements source ↗Treating a confirmed deficiency matters, but routine iron supplementation is not appropriate for everyone and too much can be harmful.
NIH Office of Dietary Supplements source ↗Vitamin D has established roles in bone, muscle and immune function. Benefit from supplementation depends partly on baseline status and intake.
NIH Office of Dietary Supplements source ↗Magnesium is essential, but research on supplemental magnesium for sleep and stress is mixed and depends on population, form and dose.
NIH Office of Dietary Supplements source ↗Small, short studies suggest possible effects on perceived stress or sleep. Preparations vary; long-term safety is uncertain, with pregnancy, liver, thyroid and interaction cautions.
NIH Office of Dietary Supplements source ↗Effects are strain-, dose- and outcome-specific. A large CFU number alone does not establish that a product supports a particular claim.
NIH Office of Dietary Supplements source ↗Caffeine can increase alertness and support some exercise outcomes. Individual effects and tolerance vary, so total milligrams per use matter.
European Food Safety Authority source ↗Creatine monohydrate has substantial evidence for high-intensity exercise capacity and training adaptations. Form, amount and finished-product quality still matter.
NIH Office of Dietary Supplements source ↗Topical retinoids have evidence for acne or photo-ageing outcomes. Strength, formulation, irritation risk and product type make a material difference.
American Academy of Dermatology source ↗Topical niacinamide is used for barrier support and appearance-related outcomes. Its position in an ingredient list does not reveal an exact percentage.
DermNet source ↗Salicylic acid appears in acne guidelines as a topical option. Concentration, formulation and skin tolerance affect use.
American Academy of Dermatology source ↗Topical hyaluronic acid mainly acts as a humectant and can support temporary hydration. It is not the same thing as injectable filler.
DermNet moisturiser source ↗The summaries are intentionally narrow and link to the source used by the receipt engine. They are not exhaustive systematic reviews. A library match gives context; a non-match says only that this version of the library does not cover the ingredient.
Last materially reviewed: 26 August 2026. Read the full methodology.