The Healthspan Map · Skin, Hair & Nails
Skin, hair, nails & wound healing
Named for Skin, hair, nails & wound healing
| Nutrient or lever | Direction | Strength | Evidence type | What was found | Source |
|---|---|---|---|---|---|
| Protein | Eat enough of | Strong | Established clinical | Protein supplies the amino acids for keratin and collagen; deficiency causes hair thinning/shedding, poor skin and impaired wound healing. | Protein for keratin/collagen (opens in a new tab) |
| Sleep quality (refreshed) | Watch this | Strong | Established clinical | Poor sleepers had double the intrinsic skin-ageing score and 30% less skin-barrier recovery at 72 h (higher TEWL). | Sleep quality & skin ageing (opens in a new tab) |
| Vitamin C | Eat enough of | Strong | Established clinical | Vitamin C is essential for collagen hydroxylation; deficiency (scurvy) causes fragile skin, corkscrew hairs, poor wound healing and bleeding. | Vitamin C & collagen (scurvy) (opens in a new tab) |
| Zinc | Eat enough of | Strong | Established clinical | Zinc deficiency causes dermatitis (acrodermatitis enteropathica), alopecia and impaired wound healing. | Zinc & skin/wound healing (opens in a new tab) |
| Added Sugars | Don't overdo | Moderate | Review / narrative | Excess added sugar drives AGE formation that cross-links and stiffens collagen, accelerating skin ageing. | "Diet and Skin Aging - From the Perspective of Food Nutrition", Nutrients 2020 (opens in a new tab) |
| Anchor foods | Watch this | Moderate | Review / narrative | A nutrient-dense whole-food diet supplies the protein, antioxidants and fats needed for skin repair and delayed ageing. | Whole-food diet & skin repair (opens in a new tab) |
| Biotin (B7) | Eat enough of | Moderate | Review / narrative | Biotin deficiency causes brittle nails, alopecia and scaly dermatitis (but supplements only help if truly deficient). | Biotin & hair/nails (opens in a new tab) |
| Cardio (moderate + intervals) | Do this | Moderate | RCT / trial | A 16-week RCT found aerobic training significantly improved skin elasticity and upper dermal structure. | Aerobic training & skin (opens in a new tab) |
| Colours a day | Watch this | Moderate | Review / narrative | Carotenoids, flavonoids and polyphenols from colourful plants protect skin from UV/ROS oxidative damage. | Antioxidants & photoprotection (opens in a new tab) |
| Cook real food | Do this | Moderate | Review / narrative | Water-based cooking (vs high-heat browning) lowers preformed dietary AGEs that damage skin collagen. | "Diet and Skin Aging - From the Perspective of Food Nutrition", Nutrients 2020 (opens in a new tab) |
| Copper | Eat enough of | Moderate | Review / narrative | Copper (lysyl oxidase) cross-links collagen/elastin; deficiency causes depigmentation, spiral hair and impaired wound healing. | Copper & collagen cross-linking (opens in a new tab) |
| Daily movement baseline | Do this | Moderate | Review / narrative | Regular activity roughly doubles cutaneous blood flow and improves vasodilatory function, supporting hydration and healing. | Activity & cutaneous blood flow (opens in a new tab) |
| EPA/DHA (omega-3) | Eat enough of | Moderate | Review / narrative | Omega-3 fatty acids support the skin lipid barrier and hydration and reduce inflammatory skin conditions and photoageing. | "Diet and Skin Aging - From the Perspective of Food Nutrition", Nutrients 2020 (opens in a new tab) |
| Iron | Eat enough of | Moderate | Review / narrative | Iron deficiency (low ferritin) is the most common nutritional cause of hair loss, plus brittle nails and dry skin. | Iron/ferritin & hair loss (opens in a new tab) |
| Niacin (B3) | Eat enough of | Moderate | Review / narrative | Niacin deficiency causes pellagra: photosensitive dermatitis (plus diarrhoea and dementia). | Niacin & pellagra (opens in a new tab) |
| Oral & skin care | Do this | Moderate | Review / narrative | Daily skincare, sun protection (UV drives ~80% of facial ageing) and gentle cleansing preserve the barrier and collagen. | Skincare & sun protection (opens in a new tab) |
| Oral & skin care | Do this | Moderate | RCT / trial | Daily skincare, sun protection (UV drives ~80% of facial ageing) and gentle cleansing preserve the barrier and collagen. | Sunscreen and prevention of skin aging: a randomized trial, Ann Intern Med 2013 (opens in a new tab) |
| Selenium | Eat enough of | Moderate | Review / narrative | Selenium supports keratin and antioxidant defence; deficiency contributes to hair and nail changes. | Selenium & hair/nails (opens in a new tab) |
| Selenium | Don't overdo | Moderate | Review / narrative | Selenium toxicity (selenosis) causes hair loss and brittle, discoloured nails plus skin lesions. | Selenosis & hair/nails (opens in a new tab) |
| Sleep duration | Watch this | Moderate | Review / narrative | Collagen synthesis, cellular repair and wound healing peak during sleep; short sleep impairs all three. | Sleep & skin repair (opens in a new tab) |
| Strength (resistance) | Do this | Moderate | RCT / trial | In the same RCT, resistance training uniquely increased dermal thickness and raised dermal ECM/collagen gene expression. | Resistance training & dermis (opens in a new tab) |
| Sugary drinks & snacks — cut back | Do this | Moderate | Review / narrative | Excess sugar cross-links collagen/elastin into AGEs, stiffening skin and accelerating wrinkling. | "Diet and Skin Aging - From the Perspective of Food Nutrition", Nutrients 2020 (opens in a new tab) |
| Tobacco / vaping — quit | Do this | Moderate | Review / narrative | Cigarette smoke degrades collagen/elastin, depletes vitamin C, impairs wound healing and causes premature ageing and hair loss. | Smoking & skin (opens in a new tab) |
| Ultra-processed food — cut back | Do this | Moderate | Review / narrative | Ultra-processed foods high in refined sugar and trans fats promote inflammation, acne and AGE formation. | "Diet and Skin Aging - From the Perspective of Food Nutrition", Nutrients 2020 (opens in a new tab) |
| Vitamin A (RAE) | Eat enough of | Moderate | Review / narrative | Vitamin A deficiency causes follicular hyperkeratosis (phrynoderma), dry skin and impaired epithelial repair. | Vitamin A & epithelium (opens in a new tab) |
| Vitamin A (RAE) | Don't overdo | Moderate | Established clinical | Vitamin A toxicity causes dry, cracked skin, cheilitis, hair loss and brittle nails. | Hypervitaminosis A & skin (opens in a new tab) |
| Vitamin D | Eat enough of | Moderate | Review / narrative | Vitamin D regulates the hair-follicle cycle and is associated with alopecia areata and telogen effluvium when deficient. | Vitamin D & hair follicle (opens in a new tab) |
| Vitamin E | Eat enough of | Moderate | Review / narrative | Vitamin E is a lipid-soluble antioxidant that protects skin lipids and supports elasticity and photoprotection. | Vitamin E & photoprotection (opens in a new tab) |
| Water / hydration | Do this | Moderate | Established clinical | Adding ~2 L/day water improved superficial and deep skin hydration and biomechanics, especially in low-consumers. | Dietary water & skin hydration (opens in a new tab) |
| Alcohol — cut back | Do this | Emerging | Review / narrative | Excess alcohol dehydrates skin, promotes ageing and impairs wound healing. | Alcohol & skin (opens in a new tab) |
| Alcohol — cut back | Do this | Emerging | Cohort / observational | Excess alcohol dehydrates skin, promotes ageing and impairs wound healing. | Impact of Smoking and Alcohol Use on Facial Aging in Women: Results of a Large Multinational Study, J Clin Aesthet Dermatol 2019 (opens in a new tab) |
| Breath/mind (slow breathing) | Do this | Emerging | Review / narrative | Physiological/psychological stress triggers telogen effluvium (delayed shedding); stress reduction supports hair and skin. | Stress & telogen effluvium (opens in a new tab) |
| Cardio / VO2max | Watch this | Emerging | Review / narrative | Habitually active people show younger skin composition than sedentary peers. | Fitness & skin composition (opens in a new tab) |
| Carotenoids (provitamin A) | Eat enough of | Emerging | Review / narrative | Dietary carotenoids act as antioxidants that help protect skin against UV-induced oxidative damage. | Carotenoids & photoprotection (opens in a new tab) |
| Folate (B9) | Eat enough of | Emerging | Review / narrative | Folate deficiency causes cheilitis, hair depigmentation and mucocutaneous hyperpigmentation. | Folate & skin (opens in a new tab) |
| Riboflavin (B2) | Eat enough of | Emerging | Review / narrative | Riboflavin deficiency causes angular cheilitis, seborrheic dermatitis and glossitis. | Riboflavin & skin (opens in a new tab) |
| Sleep regularity | Watch this | Emerging | Review / narrative | The skin has its own circadian system; disruption impairs barrier function and repair. | Skin circadian clock (opens in a new tab) |
| Supplement discipline | Do this | Emerging | Review / narrative | Supplements help hair/skin mainly when correcting a proven deficiency; megadosing (A, selenium, zinc) can worsen hair loss. | Correcting deficiency vs megadosing (opens in a new tab) |
| Total Sugars | Don't overdo | Emerging | Review / narrative | High overall sugar intake promotes glycation and AGE accumulation in skin. | "Diet and Skin Aging - From the Perspective of Food Nutrition", Nutrients 2020 (opens in a new tab) |
| Vitamin B12 | Eat enough of | Emerging | Review / narrative | Vitamin B12 deficiency causes hyperpigmentation, nail changes and hair changes. | B12 & skin/nails (opens in a new tab) |
| Vitamin B6 | Eat enough of | Emerging | Review / narrative | Vitamin B6 deficiency causes seborrheic dermatitis and cheilitis. | B6 & skin (opens in a new tab) |
| Zinc | Don't overdo | Emerging | Established clinical | Zinc above ~40 mg/day can disrupt hair follicles and induce copper deficiency (itself a cause of hair/skin changes). | NIH Office of Dietary Supplements — Zinc (opens in a new tab) |
Held for the whole Skin, Hair & Nails system
These rows name no single condition. The Map records them against the whole body system, so they are shown separately rather than folded in.
| Nutrient or lever | Direction | Strength | Evidence type | What was found | Source |
|---|---|---|---|---|---|
| Carotenoids (provitamin A) | Don't overdo | Emerging | Established clinical | Very high carotenoid intake causes carotenodermia, a harmless yellow-orange skin discoloration; no Upper Limit is set for carotenoids. | NIH ODS – Vitamin A & Carotenoids (opens in a new tab) |
| Tobacco / vaping — quit | Do this | Emerging | Established clinical | Smoking accelerates skin aging and premature wrinkling through vascular and collagen damage. | US Surgeon General report (opens in a new tab) |