Future haircare research and innovation should focus on mitigating the cumulative effects of external and internal environmental exposures known to negatively impact hair health, say scientists.

Writing in Anais Brasileiros de Dermatologia, the official publication of the Brazilian Society of Dermatology, researchers from Italy and Spain outline how the exposome—the totality of external and internal environmental factors that can influence human health–critically influences hair health and hair aging. The team identifies key exposomal factors affecting hair health: nutrition, stress, sleep, tobacco consumption, UV exposure, pollution, humidity, chlorine water, cosmetic procedures, and hairstyling practices.

“Hair weathering is influenced by a wide range of exposomal factors,” the researchers explain, yet the “intricate mechanisms” underlying the exposome influence on hair are only partially understood.

“Through a comprehensive review of current literature and emerging research findings, this study aims to enhance the understanding of exposome impact on hair health,” they write.

Internal Influences–Nutrition, Stress, Sleep, and Smoking

Nutrition, for example, plays a “crucial role” in optimal hair growth, the researchers say, with imbalances speeding up the aging process of hair. Keratin, the primary component of hair, relies on adequate protein intake for the production of healthy hair strands, and carbohydrates serve as a significant energy source for hair follicles. Vitamins in the A, E, B, and D groups and minerals like iron, zinc, and selenium also have “pivotal roles” in hair health, with low intakes associated with hair aging.