Protein linked to hair health: experts say the nutrient matters beyond workouts
Experts warn that adequate protein supports keratin production and may curb shedding, with guidance on daily targets, amino acids, and whole-food sources.
A growing body of nutrition and dermatology experts say protein intake can influence hair health beyond its role in muscle building. Hair is primarily made of keratin, a protein built from amino acids, and without enough of it, strands can lose strength and density, according to clinicians who treat hair loss and researchers who study scalp biology. As a hair surgeon, Dr. Ross Kopelman explains that when the body doesn’t get sufficient protein, it diverts amino acids to organs deemed essential for survival, which can slow hair production and leave patients reporting hair that’s weaker and more prone to shedding.
The most common pattern seen in people with insufficient protein is thinning across the scalp rather than patchy bald spots, Kopelman said. He notes that when protein intake is corrected, shedding often slows within a couple of months and density gradually improves as new hairs grow in over subsequent cycles.
Research colleagues have linked protein deficiency to brittle, sparse strands, slower regrowth and increased breakage. A study in the Journal of Dermatology found that participants with lower protein intake experienced more diffuse thinning across the scalp. Protein is vital for keratin production, and hair can weaken and break without it. The current Recommended Dietary Allowance (RDA) is 46 grams per day for women and 56 grams for men, but Kopelman suggests more for many adults—roughly 1 to 1.2 grams per kilogram of body weight per day, with higher targets up to 1.6 grams during times of stress, dieting, or recovery from surgery.
He stresses that simply upping protein intake to extreme levels isn’t a guaranteed path to faster hair growth. “What matters is consistently hitting that range, not pushing far above it,” he says. “Extra scoops of powder won’t override genetics, hormones or other limiting factors.”
Two amino acids packed in protein—lysine and cysteine—appear particularly important for keratin production. Research cited by Kopelman points to lysine’s role in hair shaft formation and iron absorption, and to cysteine’s contribution of sulfur bonds that give hair its strength. Foods rich in these amino acids include eggs, fish, poultry, legumes and seeds. “Patients often notice a difference when they shift toward more complete, amino acid–rich sources of protein in their diet,” he adds.
Plant-based diets can also support healthy hair when planned thoughtfully. Pairing legumes with grains helps ensure complete proteins, while iron, B12, zinc and vitamin D should be monitored to avoid deficiencies that can trigger shedding on their own. Doctors say whole foods offer nutrients for hair health that powders can’t match, and they caution against assuming protein powders alone will fix a thinning mane.
Dr. Shani Francis, chief wellness director of California-based Ashira Dermatology, told Everyday Health that while protein deficiencies are rare in the United States—even among vegans—they can contribute to hair loss. Other culprits, including vitamin A excess, iron deficiency, thyroid disease, infections, stress or eating disorders, may also play a role. She notes that shedding 50 to 100 hairs per day is normal and not a cause for alarm, and she cautions that supplements aren’t a miracle cure. “Protein supplements can be useful for people who struggle to meet daily targets, such as those recovering from illness or weight loss, but they’re not a replacement for a balanced diet,” Kopelman says.
In practice, experts say meeting daily protein needs, spreading intake across meals, and viewing protein as one piece of a broader health picture—along with hormones, stress management, micronutrients and genetics—offer the best path to supporting hair health. While more research is needed to determine whether eating protein far beyond daily needs can boost hair growth in otherwise healthy people, clinicians agree that hair follicles require a steady supply of amino acids from protein.
“Meet your daily needs, distribute protein evenly across meals, and don’t expect powders alone to do the work,” Kopelman said. “That’s part of a bigger picture.”
Deirdre Bardolf is a Lifestyle writer with Fox News Digital.