Selenium FAQs
← back to Selenium
5 questions
FAQs
- What is Selenium and why is it important for healthy hair and scalp function? Selenium is a trace mineral the body needs, but extra selenium has not been shown to help hair in people who are not deficient. Too much (above the US upper limit of 400 µg a day) can cause hair loss.
- Can Selenium supplements help prevent or reverse hair loss caused by nutritional deficiencies? Evidence that selenium helps hair comes mainly from rare, severe deficiency, such as long-term intravenous feeding without selenium. Extra selenium has not been shown to help people who are not deficient, and intake above 400 µg a day can cause hair loss.
- What are the risks of taking too much Selenium, and how can you get the right amount safely? Too much selenium (above the US upper limit of 400 µg a day) can cause selenosis, including hair loss and brittle nails. Most people get enough from food, and eating several Brazil nuts a day can exceed the limit.
- Is Selenium more effective when taken orally or applied topically in shampoos or serums? The two are not interchangeable and the evidence points the other way from the common assumption: topical selenium disulfide shampoo has clinical trial support for dandruff and seborrheic dermatitis, while oral selenium supplements have no reliable evidence for hair growth in people who are not deficient, and excess intake is a recognised cause of hair loss.
- How does Selenium interact with other nutrients like zinc, iron, and vitamin D in hair health? Selenium, zinc, iron and vitamin D all matter for normal hair, but only correcting a real deficiency has been shown to help. Too much selenium (above 400 µg a day) can cause hair loss.