Vitamins for Skin, Hair and Nails: What Eating vs Applying Each Shows (A, C, E, Biotin, Niacinamide)

See a doctor promptly for a mole that is changing, a sore that does not heal, sudden or patchy hair loss, a spreading rash, or signs of skin infection. Vitamins are not a substitute for that assessment. See skin and hair safety and when to see a doctor. If you take biotin, tell your clinician before any blood test: the FDA warns that biotin, often found in dietary supplements, can significantly interfere with certain lab tests and cause incorrect results which may go undetected. [1] This page is information only.

Summary by vitamin

Vitamin C

A review of the roles of vitamin C in skin health noted that vitamin C is often added to topical products, but the efficacy of such treatment, as opposed to optimizing dietary vitamin C intake, is poorly understood. [9] A systematic review of seven randomized trials (139 volunteers) of topical vitamin C found treated skin appeared smoother and less wrinkled, with significant lightening of pigmentation, but hydration improved equally on vitamin C and placebo sites. [2] The authors said more studies are needed to confirm results and assess the best concentration. [2] See vitamin C and vitamin patches and skin-delivery claims.

Vitamin A and retinoids

A 2024 systematic review called tretinoin the current gold-standard therapy for photoaging but said its poor tolerability often limits use, and that most comparison studies were of poor quality or biased. [4] A 2025 network meta-analysis of 23 trials found isotretinoin, retinol and tretinoin significantly improved fine wrinkles, and tretinoin and retinol were superior for hyperpigmentation. [10] Its limitations included commercial bias and little racial diversity. [10] The 2024 review describes tretinoin as a topical medication. [4] Discuss retinoid products with a clinician or pharmacist, including before and during pregnancy. See vitamin A excess, pregnancy and retinoid medicines.

Vitamin E

For androgenetic alopecia and telogen effluvium (two common hair loss types), a review found neither vitamin E nor biotin supplementation is supported by the literature. [3] For scars, a systematic review of six studies found three reported improved appearance and three found no improvement with topical vitamin E alone; two reported contact dermatitis or itching and rash. [5] It concluded there is not yet sufficient evidence to justify widespread use. [5] See vitamin E oil, topical use and skin.

Niacinamide (nicotinamide)

This is the vitamin B3 form, not the flush-causing form. Topical nicotinamide, alone or combined, reduced the progression of skin aging and hyperpigmentation in clinical trials and was well tolerated. [7] A 2026 review said the strongest anti-aging evidence is topical, and that long-term skin-focused trials are still needed. [11] Separately, in 386 people who had had at least two non-melanoma skin cancers, 500 mg of nicotinamide twice daily or placebo for 12 months lowered the rate of new non-melanoma skin cancers by 23%, with no evidence of benefit after stopping. [6] That is a medical use in high-risk patients, not a general skin supplement. See niacin, niacinamide and nicotinic acid compared.

Biotin for hair and nails

A review of the literature found limited research supporting biotin in healthy individuals; the 18 reported cases of improvement all involved an underlying cause of poor hair or nail growth. [8] The authors proposed that such cases are uncommon and that evidence for supplementation in healthy people is insufficient. [8] Another review notes that biotin deficiency is rare and that high biotin intake can cause falsely high or falsely low laboratory results. [3] See biotin for hair, skin and nails and biotin and lab-test interference. For other vitamins and brittle nails: Proper evidence not found (a PubMed search for biotin in brittle nails surfaced only that review).

Vitamin D and hair loss

A review reports a relationship between alopecia areata and low vitamin D levels, and states vitamin D should be supplemented if levels are low. [3] A blood test and clinician decide that. See hair shedding and thinning.