How Nutrients Affect Hair Growth
Hair growth is a complex biological process, and like the rest of your body, it needs the right nutrients to function properly. When your body is low on key vitamins and minerals, hair can become brittle, thin, or even start to fall out.
Some types of hair loss linked to nutritional issues include:
Telogen Effluvium (TE) — often triggered by stress, illness, surgery, or sudden changes in diet (like cutting calories or protein too drastically);
Androgenetic Alopecia (AGA) – although in women it is caused by hormonal imbalances, research has found links to nutritional deficiencies;
Alopecia Areata (AA) – autoimmune condition more common in patients with diabetes or thyroid disease, but studies have made associations with lower intake of certain nutrients.
The Hair Growth Cycle: A Quick Breakdown
Your hair isn’t constantly growing — it goes through phases:
Anagen: the active growth phase (about 85% of hairs at any given time);
Catagen: a short transition phase;
Telogen: the resting phase;
Exogen: the shedding phase.
Severe stress (or nutritional deficiency) can prematurely push hair into the telogen phase, causing an abnormally large amount of your strands to stop growing. After a few months, they shed all at once, which results in the hair appearing much thinner.
What Is Telogen Effluvium?
Telogen Effluvium (TE) is one of the most common forms of hair shedding and usually follows a stressful event — physically or emotionally. Your body essentially shifts a large number of hair follicles into the telogen (resting) phase of the hair cycle, meaning they stop growing and eventually fall out. If the reason behind it is not addressed, the condition can become a chronic issue.
Common triggers include:
Fever or infection
Surgery or physical trauma
Hormonal changes
Medications
Iron or protein deficiency
Psychological stress
Thyroid dysfunction
Androgenetic Alopecia (AGA): When Hair Loss Is Hormonal
Also known as male pattern baldness, AGA is a more permanent form of hair loss that’s often genetic. It’s driven by dihydrotestosterone (DHT), the „male” hormone that binds to androgen receptors in the scalp and shrinks hair follicles over time.
This process is called follicular miniaturization, and it means your hair grows back thinner — or not at all. Although it’s less reversible than TE, proper nutrition may still play a supporting role in those predisposed to the condition.
Key Nutrients That Affect Hair Health
Let’s talk about the major players when it comes to nutrients and your strands.
Zinc
Zinc is involved in numerous processes in the human body - everything from protein synthesis to cell division. Researchers also debate its role in pathways that regulate hair follicle development.
Deficiency has been linked to:
TE and brittle hair;
Gastrointestinal problems such as vomiting and diarrhea;
Immune issues, poor wound healing, and even skin rashes.
Groups at higher risk of developing a deficiency are alcoholics, pregnant women, and vegetarians, due to the lower zinc bioavailability in plant foods. Additionally, plant foods such as legumes and whole grains contain some compounds that bind to zinc and prevent its absorption in the gastrointestinal tract.
Some great food sources of zinc include:
Oysters: six oysters = 300% DRI;
Ground beef: 100 g contain 60% DRI;
Shellfish: 100 g shrimps contain 21% DRI;
Nuts: 30 g cashews contain 21% DRI.
Biotin
Often hyped in supplements, biotin (Vitamin B7 or H) is a cofactor for enzymes that help with protein and fat metabolism. Since it is abundant in a wide variety of foods and intestinal bacteria is able to synthesize some biotin, deficiencies are quite rare, but can occur due to:
Certain genetic disorders, such as key enzyme deficiencies;
Long-term antibiotic or anti-seizure medication use;
Eating raw egg whites in excess (they contain avidin, which binds to biotin).
Symptoms include skin and hair issues such as alopecia, eczema-like skin rashes, and even conjunctivitis. To avoid those, try implementing one of these biotin sources every once in a while:
Chicken liver: 75 g cooked = 400% DRI;
Beef liver: 75 g cooked = 300% DRI;
Egg yolks: one cooked egg = 33% DRI;
Mushrooms: 120 g cooked = 10% DRI;
Sunflower seeds: 20 g = 10% DRI;
Sweet potatoes: 120 g cooked = 8% DRI.
Selenium
This trace element helps protect cells from oxidative damage and plays a role in hair follicle development. Deficiency is uncommon, but may occur in those with malabsorption, long-term dialysis, or living in low-selenium soil areas such as China, Tibet and Siberia. Although many hair growth supplements include it in their ingredient list, there is not much research to support the link between selenium and hair health. What is more, selenium toxicity can do just as much harm as its deficiency, and has been found to cause hair loss, skin lesions and even memory difficulties.
Some selenium-rich foods include:
Brazil nuts: 6-8 nuts = 10x DRI;
Yellowfin tuna: 100 g = 100% DRI;
Sardines, shrimp, halibut: 100 g = almost 100% DRI;
Whole grain bread: two slices = 1/3 of the DRI;
Cottage cheese: one cup = 36% DRI;
Eggs: one egg = 25% DRI.
Iron
Iron deficiency is one of the most common nutritional deficiencies worldwide — and one of the best-established contributors to hair loss. While the exact reason behind this is unclear, scientists suggest that since hair matrix cells are one of the most rapidly dividing cells in the human body, the role of iron in DNA synthesis could be the key here. Additionally, the amino acid L-lysine may boost iron absorption in those who fail to respond to supplementation. This could be crucial for groups at risk of iron deficiency such as premenopausal women (due to blood loss during menstruation), vegans/vegetarians, and people with malabsorption disorders.
Top iron food sources include:
Beef liver: 100 g = 36% DRI;
Clams: 100 g = 17% DRI;
Ground beef: 100 g = 15% DRI;
Dark chocolate: 30 g = 20% DRI.
Plant sources such as spinach, lentils and quinoa also contain good amounts of iron, however, it is not as bioavailable as the one from animal sources. On the bright side, Vitamin C might boost absorption, so consider implementing more citrus fruits, broccoli, kiwis and bell peppers.
Should You Take Hair Supplements?
Here’s the truth: supplements only help if you’re deficient. All of the research supporting the good effects of these nutrients was done on patients who lacked them in the first place, and excessive intake is unlikely to do much. In some cases, as with selenium, it could even cause serious side effects.
So before buying that Instagram-famous hair gummy, get your bloodwork done. Talk to a healthcare provider to check for deficiencies in iron, zinc, biotin, or selenium.
The Bottom Line
Hair loss is often multifactorial, but your diet is one part of the equation you can control. Ensuring you’re getting the right nutrients — especially if you follow a restricted diet — can go a long way in supporting hair growth and health.
Sources:
Almohanna, H.M., Ahmed, A.A., Tsatalis, J.P. et al. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb) 9, 51–70 (2019). https://doi.org/10.1007/s13555-018-0278-6
Guo EL, Katta R. Diet and hair loss: effects of nutrient deficiency and supplement use. Dermatol Pract Concept. 2017 Jan 31;7(1):1-10. doi: 10.5826/dpc.0701a01. PMID: 28243487; PMCID: PMC5315033.
Rushton DH. Nutritional factors and hair loss. Clin Exp Dermatol. 2002 Jul;27(5):396-404. doi: 10.1046/j.1365-2230.2002.01076.x. PMID: 12190640.