Skincare from within: which nutrients actually support the skin

What you eat shows on your skin — at least in one direction. A deficiency in certain micronutrients shows up on the skin relatively quickly. EFSA has explicitly recognized seven substances for the maintenance of normal skin, plus vitamin C for collagen formation. What goes beyond marketing promises and what's actually sensible — coming up. For the overall overview of all micronutrients, see the pillar Micronutrients.

What EFSA permits for skin

Skin-related action statements are tightly regulated in the EU. Regulation 432/2012 lists the following claims for skin scientifically validated by EFSA:

• Biotin (B7) — contributes to the maintenance of normal skin
• Niacin (B3) — contributes to the maintenance of normal skin
• Riboflavin (B2) — contributes to the maintenance of normal skin
• Vitamin A — contributes to the maintenance of normal skin
• Zinc — contributes to the maintenance of normal skin
• Iodine — contributes to the maintenance of normal skin
• Vitamin C — contributes to normal collagen formation for the normal function of the skin

What EFSA doesn't permit: claims about wrinkle reduction, younger appearance, improved skin appearance with acne, cellulite effect, or general rejuvenation promises. Such claims still appear in advertising — but legally they are gray zone, and the CJEU ruling C-386/23 (2025) tightened the screws particularly on plant-substance promises.

The most important skin micronutrients in detail

Biotin (B7)

The classic in beauty marketing — and one of the few substances that backs the marketing hype with a real EFSA claim. Biotin is part of enzymes in the metabolism of fatty acids and amino acids, exactly the building blocks needed for the skin.

DGE estimated value for adults: 30–60 µg/day. Rich sources: egg yolk, yeast, nuts (especially walnuts), oats, liver. Real biotin deficiency is rare in Germany — risk groups are people on prolonged parenteral nutrition, severe alcohol disorder or very monotonous diets with lots of raw egg white (avidin in egg white binds biotin).

Niacin (B3) and riboflavin (B2)

Both B vitamins are authorized for the maintenance of normal skin. More on B vitamins overall in B vitamins overview — also on B6, B12 and folate.

DGE: niacin 11 mg (women) to 16 mg (men) niacin equivalents/day; riboflavin 1.1–1.4 mg/day.

Vitamin A (retinol and carotenoids)

Vitamin A plays a central role in the differentiation of skin cells — that is, the process by which young cells develop into specialized skin cells. DGE: 0.8 mg retinol equivalent (women) or 1.0 mg (men) per day.

Sources: liver (very high concentrations — pregnant women avoid), egg yolk, whole milk, cheese. Plant pro-vitamin A sources (carotenoids) such as carrots, sweet potato, pumpkin and kale provide the precursor that the body converts.

Vitamin C

For the skin, vitamin C is a special case: it's involved in the body's own collagen formation, the structural protein of the dermis. That's not a "rejuvenation promise" but an EFSA-authorized functional claim.

DGE: 95 mg (women) / 110 mg (men); smokers 135 / 155 mg. Rich sources see Antioxidants and cell protection.

Zinc

Zinc is a cofactor for hundreds of enzymes — including those involved in skin renewal and wound healing. DGE: 7–10 mg (women) / 11–16 mg (men), depending on the phytate content of the diet.

Rich sources: beef, pumpkin seeds, sunflower seeds, hard cheese, lentils, cashews. With a plant-based diet, at the upper end of the requirement range.

Iodine

Rarely mentioned as a beauty substance, but EFSA-recognized for normal skin. DGE estimated value: 200 µg/day. In Germany, iodized table salt, fish and dairy usually cover the need with a balanced diet.

What you often read on labels but is NOT approved

In beauty supplement advertising, claims appear that lack EFSA foundation. Examples:

• Drinkable collagen for wrinkle reduction — no approved claim
• Hyaluronic acid capsules for "skin moisture from within" — no approved claim
• Q10 as a rejuvenating substance — no approved claims
• MSM and sulfur compounds — no approved claims
• Silica for connective tissue — no approved claims

As long as no EFSA claim is authorised, marketing texts and labels must not assert any effect for these substances — evidence from controlled studies was not sufficient under the EFSA process. Anyone investing money in high-priced beauty complexes should know that.

What the skin actually needs systemically

Three building blocks that come into play in nearly every skincare constellation:

• Sufficient protein: the skin is constantly being renewed; without a protein basis, the supply of amino acids for collagen, keratin and elastin remains tight. More in Amino acids and sport.
• Essential fatty acids: omega-3 and omega-6 in balanced ratio. The skin barrier depends on intact fatty acid synthesis. See Omega-3 for heart function.
• Water: drink enough (DGE: ~1.5 liters from beverages, more depending on load). Drinking more than needed doesn't help the skin further — water balance is regulated by the kidney.

When skin problems belong with the GP or dermatologist

Severe or persistent skin problems aren't a matter for self-diagnosis with micronutrient tables:

• Persistent acne beyond puberty, with scarring
• Extensive eczema, psoriasis or atopic dermatitis
• Sudden changes in moles or skin spots
• Wound healing disorders without a recognizable cause
• Cracked corners of the mouth that don't go away after 2–3 weeks of micronutrient attention — blood panel at the GP

Micronutrients can contribute, but they don't replace medical clarification of skin diseases.

If you want to look at your supply

With diffuse complaints (dry skin, brittle nails, cracked corners of the mouth), it's worth looking at micronutrient supply in a structured way — before investing in expensive beauty capsules. The free Vital-Check gives a written assessment in a few minutes and shows where a conversation with the GP makes sense. For specific skin diseases, however, the dermatologist remains the right address.