Can Selenium Supplements Help Prevent or Reverse Hair Loss from Nutritional Deficiency? A Critical Examination of the Evidence

Hair loss is a complex biological phenomenon with a wide range of causes, among them genetics, hormones, autoimmune conditions, stress, and nutritional factors. Among the nutrients often discussed in the context of hair health is selenium, a trace mineral essential to many cellular processes. Yet when it comes to selenium’s role in preventing or reversing hair loss specifically due to nutritional deficiencies, the scientific evidence is nuanced and often contradictory. A careful scrutiny of peer-reviewed research reveals where the gaps in knowledge lie, and where claims exceed what the data supports.

Understanding this issue requires clarity about what selenium is, how hair growth works, and what the clinical literature has actually shown. This discussion therefore emphasizes primary research findings, explains the physiological background in accessible language, and identifies the strengths and limitations of the existing evidence.

Selenium: A Trace Mineral With a Large Role in Human Biology (But Not Necessarily in Hair Growth)

Selenium is a trace element—meaning the human body requires it in very small amounts—to manufacture specialized proteins known as selenoproteins. These proteins include glutathione peroxidases, which are important antioxidant enzymes that help prevent cell damage from reactive oxygen species. Selenium also has roles in immune function and thyroid hormone metabolism. However, being biologically essential does not automatically mean that taking more of it improves every aspect of health, such as hair growth.

According to clinical reviews, selenium is indeed essential for the synthesis of more than 35 selenium-dependent proteins in humans. These proteins include antioxidants that protect cells, including those in hair follicles, from oxidative stress, a process that can influence the hair growth cycle. However, this biochemical link is not the same as direct proof that selenium supplementation can prevent or reverse hair loss in people without clear deficiency. In fact, in many regions, typical diets already provide adequate selenium for daily human requirements, and supplementation is unnecessary unless deficiency is documented.

What the Clinical Evidence Shows: Rare Cases Linking Selenium Deficiency to Hair Changes

When discussing hair loss related to selenium deficiency, the strongest evidence stems from rare clinical situations in which people lack selenium to an extreme degree. These cases are mostly found in individuals who are already facing severe nutritional compromise, such as patients receiving long-term total parenteral nutrition (TPN) without adequate selenium, and not in the typical population.

**Research dating back decades describes children on TPN solutions without selenium who developed symptoms including hair pigmentation loss and, in some cases, sparse hair growth. ** After selenium was added back to their nutrition regimen, improvements in hair pigmentation and other deficiency symptoms were observed typically over several months. This type of evidence suggests that in the specific context of frank selenium deficiency, replacing selenium can help reverse some biological effects of the deficiency—including some changes in hair appearance.

This evidence, however, does not demonstrate that selenium supplements will prevent or reverse hair loss in people whose selenium levels are already normal. It also does not establish that selenium alone is sufficient to resolve deficiency-related hair loss because many other nutrients and metabolic factors can play a role.

Research in Hair Loss: Mice and Mechanisms, Not Humans

There is at least one study in animal models showing hair abnormalities with both selenium deficiency and excess. In mice, diets either lacking selenium or containing excessive selenium resulted in hair loss and changes in the hair cycle. In that study, selenium imbalance altered the balance between proteins that regulate cell death in hair follicle cells, which was believed to disrupt the normal hair growth cycle. Because this study was conducted in mice, its relevance to humans must be interpreted with caution. Animal metabolism and hair growth cycles differ from human physiology in important ways, and what happens in a controlled laboratory setting does not always translate directly to human clinical outcomes.

Human Studies: Mixed Results and Confounding Factors

When it comes to controlled human research specifically investigating selenium supplements for hair loss, the landscape is limited and inconclusive. A systematic review that examined numerous micronutrients found possible links between mineral deficiencies and hair loss, but selenium was not singled out as a primary factor in human hair loss outside of deficiency contexts. The review highlighted evidence deficits and inconsistency in the clinical literature; for selenium specifically, there is no high-quality evidence showing that supplementation improves hair growth in the general population. This same review emphasized that many nutrient supplements that are marketed for hair growth lack rigorous evidence.

Some combination supplements that include selenium have been tested as adjuncts to established hair loss treatments such as minoxidil or finasteride, and in those cases some trials reported mild improvements in clinical outcomes. However, in those trials selenium is one of many compounds, meaning that the observed improvements cannot be attributed to selenium alone. Thus, even where positive effects are reported in combination formulas, the specific contribution of selenium remains unproven.

Selenium Toxicity: A Much Better Established Cause of Hair Loss Than Deficiency

Crucially, while the evidence for selenium deficiency contributing to hair loss is weak and limited to specific atypical clinical situations, the evidence that excessive selenium intake can cause hair loss is well documented. Selenium toxicity, known as selenosis, can result in symptoms including hair loss, brittle nails, gastrointestinal disturbances, neurological symptoms, and fatigue. This is not theoretical: numerous case reports and occupational health studies describe hair loss linked to high levels of selenium, either environmental or from supplements. Some reports even describe severe hair loss and systemic symptoms following ingestion of misformulated supplements containing extremely high selenium doses.

Why This Matters: Misleading Claims and Consumer Risks

Despite the limited evidence, selenium appears in many commercial “hair growth” supplements. Because the supplement industry is far less regulated than pharmaceutical drugs, consumers may be exposed to products that either do not contain what the label claims or that contain unintended high doses of selenium. In such cases, not only might there be no benefit, but there is a higher chance of causing harm.

References

Almohanna, H. M., Ahmed, A. A., & Tsatalis, J. P. (2018). The Role of Vitamins and Minerals in Hair Loss: A Review. PMC, Article 6380979. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC6380979/

Civas, E., & Akpınar, Ü. (2023). Selenium in the supplement as the probable cause of hair loss and nail dystrophy. Journal of Cosmetic Dermatology, 23(1), 361–363. Retrieved from https://pubmed.ncbi.nlm.nih.gov/37594173/

Guo, E. L., & Katta, R. (2017). Diet and hair loss: effects of nutrient deficiency and supplement use. PMC. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC5315033/

Neumann, V. (1987). Macrocytosis and pseudoalbinism: manifestations of selenium deficiency. Journal of Pediatrics, 111(5), 711–717. Retrieved from https://pubmed.ncbi.nlm.nih.gov/3117996/

Selenium toxicity and deficiency data. (2001). Reviews on Environmental Health. Retrieved from https://pubmed.ncbi.nlm.nih.gov/12041880/

Selenium imbalance effects in mice. (2011). PubMed. Retrieved from https://pubmed.ncbi.nlm.nih.gov/21366699/

Systematic review of selenium and micronutrients. (2025). PMC. Retrieved from https://pubmed.ncbi.nlm.nih.gov/39440586/