Why it's essential: Vitamin C is perhaps the most important antioxidant for skin health. It's required for collagen synthesis, protects against free radical damage from UV exposure and pollution, and helps brighten hyperpigmentation.

Supplement recommendation: Look for L-ascorbic acid formulations with concentrations between 10-20% for topical use. For oral supplements, 500-1000mg daily is generally sufficient for skin benefits.

Why it's essential: Vitamin E is a fat-soluble antioxidant that works synergistically with vitamin C to protect skin cells from oxidative stress. It also has anti-inflammatory properties and helps maintain skin barrier function.

Supplement recommendation: Topical vitamin E (as tocopherol or tocopheryl acetate) works best when combined with vitamin C. Oral supplementation of 400 IU daily can support skin health, but excessive amounts may have diminishing returns.

Why it's essential: Vitamin A is crucial for cell growth and differentiation. In its retinoid form, it's one of the most researched anti-aging ingredients, promoting cell turnover and collagen production.

Supplement recommendation: Topical retinoids (retinol, tretinoin) are highly effective for skin rejuvenation. Oral supplementation should be approached cautiously due to potential toxicity at high doses—consult your dermatologist before taking vitamin A supplements.

Why it's essential: Biotin plays a critical role in fatty acid synthesis and cell growth, making it particularly important for maintaining healthy skin, hair, and nails. While deficiency is rare, adequate biotin supports overall skin health.

Supplement recommendation: Most people get adequate biotin from their diet. If supplementing, 30-100mcg daily is generally sufficient. Be cautious of megadoses, which can interfere with lab tests.

Why it's essential: Niacinamide is one of the most versatile and well-tolerated skincare ingredients available. It addresses multiple skin concerns simultaneously without causing irritation.

Supplement recommendation: Topical niacinamide (2-5%) is highly effective for most skin types. Oral supplementation of 500-1000mg daily may provide additional benefits, but consult your healthcare provider first.

Why it's essential: Often called the "sunshine vitamin," vitamin D plays a crucial role in immune function and skin cell growth. Research shows it may help manage inflammatory skin conditions.

Supplement recommendation: Many people are deficient in vitamin D. Supplementing with 1000-2000 IU daily is common, but get your levels tested first. Topical vitamin D is being researched but not yet widely available.