Zinc

What it is

Zinc is an essential trace mineral used by more than 100 enzymes. Deficiency signs include slow growth, diarrhea, hair loss, a rash around the mouth, nail changes and poor immunity. The US recommended intake is 11 mg/day for men and 8 mg/day for women, and the US adult upper level is 40 mg/day of elemental zinc. Saper 2009 The European Food Safety Authority sets a lower upper limit of 25 mg/day.

It is sold as a supplement in the US, EU and UK. The EU permits the claim that zinc contributes to normal hair, which reflects avoiding deficiency, not extra growth. Zinc pyrithione in anti-dandruff shampoo is a different, topical use; see zinc pyrithione.

How it works

Deficiency causes hair loss. In a review of 231 children with acrodermatitis enteropathica, 75.9% had measurable zinc deficiency and 91.4% of treated children responded to zinc, usually at 1-3 mg/kg/day. Cui 2025 Five adults with zinc-deficiency telogen effluvium recovered or improved on oral zinc. Karashima 2012

People at risk of deficiency include those with Crohn disease, celiac disease or short bowel, heavy alcohol use, vegan diets, pregnancy and lactation, and gastric bypass.

The idea that zinc blocks DHT comes from a 1988 lab study in which zinc sulfate inhibited 5-alpha-reductase in skin extracts, but only at concentrations roughly 200 times those in normal blood. Stamatiadis 1988 There is no human evidence that oral zinc lowers scalp DHT or slows pattern loss.

What the studies show

• In 312 patients with alopecia areata, pattern loss or telogen effluvium versus 30 controls, mean zinc was 84.3 vs 97.9 micrograms/dL (p = 0.002), lower in every group. Kil 2013
• A meta-analysis of 34 studies (4,931 people) found lower zinc (SMD -0.69) in alopecia areata. Wu 2025 A further meta-analysis of 113 studies found zinc lower in alopecia areata, psoriasis and vitiligo. Shao 2025 An earlier meta-analysis of 10 studies agreed. Jin 2017
• Zinc was lower in alopecia areata and tracked with severity in two case-control studies (50 vs 50, and 32 vs 32). Abdel Fattah 2016 Lalosevic 2023
• In 90 women with chronic telogen effluvium versus 90 controls, zinc was lower while ferritin, B12 and vitamin D were not. Durusu Turkoglu 2024
• In 60 men with pattern loss versus 60 controls, zinc was lower but not related to severity. El-Esawy 2019
• After weight-loss surgery (18 studies, 2,538 people), 57% had hair loss, and lower zinc was borderline associated with it (p = 0.05). Zhang 2021
• A large analysis of 23,975 people found a statistically significant but clinically minor gap in median zinc (96 vs 99 micrograms/dL) and advised against routine zinc testing for hair loss. Liran 2025
• An uncontrolled study gave 15 alopecia areata patients with low zinc a "50 mg" zinc gluconate tablet daily for 12 weeks. Serum zinc rose from 56.9 to 84.5 micrograms/dL and 9 of 15 had some regrowth, which was not statistically significant. With no control group, and patchy alopecia areata often remitting on its own, it proves little. Park 2009
• A systematic review of supplements in people without known deficiency listed zinc among interventions with relatively higher-quality evidence of potential benefit. Drake 2023

How it's used in studies

Trials used a "50 mg" zinc gluconate tablet daily for 12 weeks in alopecia areata, and 1-3 mg/kg/day for acrodermatitis enteropathica. Labels list elemental zinc differently by salt (gluconate, sulfate, picolinate), so compare doses as elemental zinc.

Side effects and safety

• Copper deficiency is the main chronic risk. Long-term intake above the upper level can suppress immunity, lower HDL cholesterol and cause anemia and copper deficiency, which can progress to spinal cord and nerve disease. Saper 2009
• Denture cream is a hidden source. Heavy chronic use explained high zinc, low copper and neurological disease in every patient of an 11-person series. Nations 2008 Hedera 2009
• Among 2,646 Japanese patients on oral zinc therapy, 3.8% had copper deficiency reported. Risk rose with dose, kidney disease, age 70 or over and female sex. Hiyama 2026
• High doses cause metallic taste, nausea, cramps and diarrhea.
• No human cases of zinc excess causing hair loss were found. In mice, high-dose oral zinc lightened newly grown hair. Plonka 2006

Bottom line

Consider a zinc test or supplement when there is a reason: malabsorption, heavy alcohol use, weight-loss surgery, a strict vegan diet, a rash around the mouth or diarrhea, or alopecia areata. Routine testing for ordinary hair loss is low-yield. A diet or multivitamin that meets the recommended intake is enough for most people; avoid stacking several zinc products that push intake above the upper limit for months. If a clinician prescribes higher doses, copper and blood counts should be monitored. Zinc is not an antiandrogen treatment for pattern loss; see finasteride and minoxidil. Discuss with a doctor.

Fun facts

• Denture adhesive turned out to be the hidden zinc source behind a mysterious nerve disease. Patients with ill-fitting dentures who used large amounts swallowed enough zinc to drain their copper. Hedera 2009
• High-dose zinc in drinking water turned black mice's new hair a lighter brown over successive hair cycles. Plonka 2006