Hair loss is a common problem that affects both men and women. It can be caused by a variety of factors including genetics, hormonal changes, medical conditions, medications, stress, aging, and nutritional deficiencies. Zinc is an essential mineral that plays a key role in many aspects of cellular metabolism and tissue growth and repair. Some studies have suggested that zinc deficiency may contribute to hair loss, and that zinc supplementation may help restore hair growth in some cases. In this article, we’ll explore the research behind whether zinc can help treat hair loss.
What causes hair loss?
Hair follicles go through regular cycles of growth, rest, and shedding. Hair loss occurs when this cycle is disrupted, and hair follicles stop producing new hairs. The most common causes of hair loss include:
– Androgenetic alopecia: This genetic form of hair loss, also known as male or female pattern baldness, affects both men and women. It occurs when hair follicles are sensitive to the hormone dihydrotestosterone (DHT), causing them to shrink and stop producing new hairs.
– Alopecia areata: This autoimmune disease causes patchy hair loss when the immune system mistakenly attacks the hair follicles. It can occur at any age and on any part of the body.
– Telogen effluvium: Temporary increased shedding caused by physical or emotional stress, high fever, childbirth, nutritional deficiencies, crash dieting, medications, or other shocks to the system. The hair growth cycle is pushed into a resting phase prematurely.
– Nutritional deficiencies: Lack of key nutrients including protein, iron, zinc, biotin, and essential fatty acids can disrupt the hair growth cycle and cause excessive shedding.
How is zinc involved in hair growth?
Zinc is an essential mineral that is required for proper functioning of many enzymes and biochemical reactions in the body. It plays a key role in cell division, protein synthesis, hormone production, and absorption of nutrients. Zinc is also involved in the normal division and growth of hair follicles:
– Zinc is essential for DNA and protein synthesis in hair follicle cells. This controls the rate of new hair production.
– It helps regulate levels of androgens like testosterone and DHT, which can bind to hair follicles and slow hair growth.
– Zinc has antioxidant properties that counteract oxidative stress, inflammation, and cell damage – all factors that can impair follicle function.
– It enables proper absorption of iron, B vitamins, and other nutrients integral to hair health.
– Zinc contributes to optimal immune function. Excessive inflammation can inhibit hair growth.
When zinc levels are low, these vital processes are disrupted. Hair follicles may degrade over time and enter a prolonged resting phase with no new hair growth.
Is there a link between zinc deficiency and hair loss?
Several studies have found an association between low zinc levels and hair loss:
– A 2013 cross-sectional study of 312 people found significantly lower serum zinc levels in both males and females with alopecia areata compared to healthy controls. Zinc levels decreased as hair loss severity increased.
– A 2015 literature review summarized findings from 27 studies showing that zinc levels were frequently lower in people experiencing alopecia areata, male pattern baldness, and telogen effluvium.
– According to a 2020 meta-analysis of 18 studies with over 2000 participants, serum zinc concentration was considerably lower in those with alopecia areata compared to healthy individuals.
– Research in mice shows that a zinc-deficient diet can induce hair loss, while zinc supplementation can promote hair re-growth.
However, not all studies have found a definitive link between zinc status and hair loss. More research is still needed to establish whether zinc deficiency directly causes hair loss in humans. It may be a contributing factor rather than a sole cause. Individuals can have normal zinc levels and still experience hair loss for other reasons.
How could zinc supplements help with hair loss?
If low zinc status does contribute to hair follicle damage, then it’s theoretically possible that zinc supplementation may aid hair growth under certain circumstances. Here are some of the proposed mechanisms:
– Providing the raw materials needed for protein synthesis, DNA replication, and new tissue generation in hair follicles
– Reducing follicular damage from oxidative stress and inflammation
– Blocking the effects of elevated androgens like DHT on hair follicles
– Improving absorption of iron and other nutrients needed for healthy follicles
– Optimizing immune function and reducing excessive autoimmune reactions
– Strengthening the structural proteins that make up hair strands
However, there is still debate around whether oral zinc supplements reliably improve hair growth. Not all trials demonstrate a clear benefit, especially in non-deficient individuals. Here is an overview of some of the research:
Studies showing positive effects
– A 2013 study of alopecia areata patients found that 50mg zinc sulfate daily led to significant hair re-growth after 12 weeks. Only mild gastrointestinal side effects were reported.
– In a 2014 trial of 48 people with telogen effluvium, taking zinc supplements for 3 months reduced hair shedding and increased hair thickness and weight compared to placebo.
– A small study in 2018 gave varying doses of zinc gluconate (50-150mg/day) to 9 females with pattern hair loss. After 6 months, all experienced decreased shedding and increased hair density.
Studies showing minimal or mixed effects
– A 2019 double-blind trial found no improvement in female pattern hair loss after taking 50mg/day zinc gluconate for 6 months. However, the control group unexpectedly also had increased hair growth.
– Researchers in Egypt (2020) reported that 200mg/day zinc sulfate for 3 months only slightly improved hair density in women with pattern hair loss compared to placebo (+7.4% vs +0.7%)
– In a 2021 meta-analysis of 9 studies, there was a modest benefit of zinc supplementation on increasing hair growth. However, results were inconsistent across trials.
The mixed research results suggest that zinc supplements may occasionally improve hair loss, but are unlikely to be a miracle cure. Overall hair benefits seem small and not guaranteed for everyone.
Are there risks or side effects from too much zinc?
Oral zinc supplements are generally safe when taken at the recommended daily allowance of 8-11 mg for adult women and men respectively. However, excessively high doses over a prolonged period can potentially cause adverse effects:
– Nausea, vomiting, diarrhea, abdominal cramps from excess zinc intake.
– Copper deficiency anemia – zinc interferes with copper absorption long-term.
– Impaired immune system function.
– Lower HDL (“good”) cholesterol levels.
– Kidney problems from accumulation of excess zinc.
Topical zinc preparations like shampoos and lotions are less likely to cause side effects as they are not systemic. But allergic contact dermatitis is possible.
The upper tolerable limit is 40 mg/day of elemental zinc. Only larger doses (over 150 mg/day) for months consistently show negative effects. Still, long-term mega-dose zinc supplementation should be avoided without medical oversight.
Should people with hair loss take a zinc supplement?
Despite the promotional claims that zinc restores hair growth, the overall evidence is still considered weak. Routine zinc supplementation is unlikely to prevent or cure hair loss for the average person. However, there are certain situations where zinc supplements may be appropriate:
– If you have a confirmed zinc deficiency. Getting zinc levels tested can identify people who may benefit.
– For managing alopecia areata. Some research suggests zinc may help compared to other types of hair loss.
– When hair loss is accompanied by symptoms like impaired wound healing, frequent infections, changes in taste or smell, or rashes. These can indicate low zinc.
– As an adjunct to conventional treatments like minoxidil, spironolactone, finasteride etc. Zinc could provide additional nutritional support.
– To correct any marginal zinc insufficiency. People with poor diets, malabsorption conditions, or at higher need may require more than normal.
The recommended daily dose for hair loss is typically 50 mg or less for up to 6 months. This is considered a safe, low-risk approach if people want to try zinc. But be aware that benefits are uncertain. Always discuss using supplements with your healthcare provider first.
Are there any risks for women taking zinc while pregnant or breastfeeding?
During pregnancy and breastfeeding, the recommended dietary allowance of zinc rises to 11-12 mg daily to support increased maternal and fetal needs. At this level, zinc is considered safe and beneficial. However, extremely high doses above 40 mg/day should be avoided as they could impair copper status and potentially cause other prenatal complications.
Here are some important considerations around zinc intake for pregnant and nursing women:
– Pre-natal vitamins already contain sufficient zinc for most women. Extra supplementation may not be needed.
– Excessive zinc intake can interfere with the absorption of copper, iron, and other minerals. This can contribute to anemia or bone abnormalities during fetal development.
– Nausea is a common side effect of taking high zinc doses, especially on an empty stomach. This can aggravate normal pregnancy nausea.
– Limited research shows that large doses of zinc in later pregnancy may induce labor or cause preterm delivery.
– No more than 40 mg of zinc should be consumed from both food and supplements combined. Upper limits are even lower for adolescents.
– Zinc excess is excreted in breast milk and absorbed by the infant. Impaired iron absorption or copper deficiency can result.
Unless correcting a known zinc deficiency, most prenatal specialists recommend getting zinc from a healthy, balanced diet rather than supplements alone. Food sources provide zinc in combination with other essential nutrients.
What are the best food sources of zinc?
Rather than relying on supplements, getting sufficient zinc from whole food sources is ideal to prevent deficiency and support hair growth from within. The best dietary sources of zinc include:
– Oysters and other shellfish – A 3-ounce serving of oysters contains 74 mg zinc or approximately 6x the RDA. Other good options are crab, lobster, and mussels.
– Meats – Beef, lamb, chicken, and duck all supply zinc as well. A roasted chicken breast has 1 mg of zinc.
– Beans and legumes – Lentils, chickpeas, beans, tofu, and tempeh are plant-based zinc sources. A 1/2 cup serving of lentils has 1.7 mg.
– Nuts and seeds – Squash and pumpkin seeds, cashews, almonds, and pine nuts are all rich in zinc. An ounce of dry roasted cashews provides 1.6 mg.
– Dairy foods – Milk, cheese, and yogurt supply varying amounts of zinc. One cup of plain yogurt has 1.4 mg.
– Whole grains – Choose fortified whole grain breads, wheat germ, oats, brown rice and quinoa. 1 slice of whole wheat bread has 0.9 mg zinc.
– Some fruits and vegetables – The most zinc-rich choices are mushrooms, spinach, kale, garlic, cabbage, pumpkin, chickpeas and tomatoes.
For optimal absorption, pair zinc foods with a source of protein like meat or dairy. Avoid overcooking zinc-containing foods which depletes the mineral content.
What is the recommended daily intake of zinc for hair growth?
The recommended daily intake of zinc is:
– Males age 14 and older: 11 mg per day
– Females age 14 and older: 8 mg per day
– Pregnant women 14-18 years old: 12 mg per day
– Pregnant women 19 years and older: 11 mg per day
– Breastfeeding women 14-18 years old: 13 mg per day
– Breastfeeding women 19 years and older: 12 mg per day
Consuming the RDA amount from varied food sources alone is adequate to maintain normal hair growth and prevent zinc deficiency in most healthy individuals.
People at higher risk of zinc deficiency may need up to 50 mg daily for a limited time to correct the deficiency and stimulate hair regrowth:
– Those with poor dietary intake or conditions that impair nutrient absorption like Crohn’s disease or bariatric surgery.
– Vegetarians and vegans who do not eat zinc-rich meat and seafood.
– Individuals with alopecia areata or other conditions causing excessive hair shedding.
However, there is little evidence that healthy non-deficient individuals require extra zinc for hair health. Megadoses over the RDA have not been proven beneficial and may instead cause adverse effects.
Should I take a zinc and biotin supplement for hair loss?
Biotin and zinc are both essential nutrients involved in hair growth that are often paired together in supplements marketed for hair loss. However, there is limited evidence that this combination provides added benefit:
– Biotin is a B-complex vitamin that aids keratin formation. Deficiency causes hair thinning, but supplements only help for those who are deficient, which is rare.
– Neither nutrient lacks strong clinical evidence as effective hair loss treatments on their own. Taking them together does not enhance their efficacy.
– Megadoses of biotin like 10,000 mcg can actually impair zinc absorption and induce deficiency.
– Biotin does not require zinc for its absorption or utilization in the body.
– Taking either nutrient alone at moderate therapeutic doses is likely just as effective.
– Both zinc and biotin are already present in a typical multi-vitamin. Most people get enough from diet alone.
Unless diagnosed with a deficiency, zinc and biotin supplementation both appear unlikely to reverse hair loss. While these nutrients may promote general hair health, individuals are unlikely to see dramatic cosmetic improvements in alopecia from over-the-counter supplements.
Should I rub zinc directly on my scalp for hair growth?
Applying topical zinc directly to the scalp is not proven to treat hair loss, though some shampoos and lotions containing zinc ingredients are marketed for hair growth. Here are some points on whether massaging zinc oils, serums or creams into the scalp is beneficial:
– Zinc is not well absorbed through skin and does not reach the hair follicles. Oral supplements are more effective for improving internal zinc status.
– Topical zinc can potentially help treat dandruff by reducing scalp inflammation and fungal overgrowth. This may indirectly improve hair health.
– In lotion form, zinc may reduce hair shedding by strengthening and thickening each hair strand. But it does not directly stimulate new growth.
– Compounds like zinc pyrithione have antimicrobial effects. But shampooing is not thought to improve alopecia.
– Applying excessive amounts of topical zinc can potentially cause buildup, clogged hair follicles, irritated skin, or dryness.
While topical zinc is an easy home remedy, oral supplementation or medications are more clinically proven for growing new hair. Always patch test topical zinc first to check for skin sensitivity or allergic reactions. Consult a dermatologist for effective treatments.
Conclusion
In summary, there is some preliminary evidence that zinc supplementation may support hair growth in those with a confirmed zinc deficiency, alopecia areata, or other hair shedding disorders. However, it appears unlikely to reverse male or female pattern baldness on its own. While severe zinc deficiency can trigger hair loss, marginal insufficiency does not necessarily cause it. For healthy individuals with no deficiency, zinc supplements are unlikely to prevent or cure alopecia. Consuming adequate zinc through a balanced diet seems to be sufficient for maintaining normal hair growth in most people. Higher doses should only be considered therapeutically and with medical guidance. More research is still needed to fully establish the effectiveness and safety of zinc supplementation for treating hair loss.
