Selenium can be toxic to animals, causing serious health issues, especially in horses.
78 citations,
December 2011 in “Clinical toxicology” Excessive selenium from a supplement caused toxicity but patients recovered with care.
12 citations,
June 2023 in “Journal of trace elements in medicine and biology” Eating too much selenium can cause bad breath, hair loss, and nail changes, with harmful effects starting at low daily doses.
30 citations,
January 2023 in “EFSA journal” Adults should not consume more than 255 micrograms of selenium per day to avoid risk of hair loss and other side effects.
134 citations,
December 2018 in “Dermatology and Therapy” Some vitamins and minerals like vitamin D and iron can help with certain types of hair loss, but more research is needed for others.