Vitamins and minerals: allies (when documented) against hair loss

IN BRIEF

• Deficiencies of certain micronutrients (iron, vitamin D, zinc, biotin) are often investigated when evaluating diffuse hair loss, but the relationship is not always causal.
• Scientific literature suggests that correcting a deficiency can help in some cases; however, supplements are not a universal solution, and targeted tests are needed before intervening.
• Useful tests include ferritin, 25-OH-vitamin D and, in selected cases, zinc and vitamin B12; interpretation requires clinical contextualization.
• Observational studies and systematic reviews show associations, but causal evidence and randomized studies on targeted supplementation are still limited.

Abstract: what does science say?

Vitamins and minerals are essential components for the hair cycle: they participate in keratin production, follicular cell metabolism, and antioxidant defense. Available evidence shows associations between hair loss (particularly telogen effluvium and some forms of non-scarring alopecia) and low levels of ferritin, vitamin D, zinc, or biotin in some patient groups. However, most data come from observational studies, case-control studies, and reviews; evidence that supplementation improves outcomes in non-deficient individuals is modest or inconsistent. Therefore, it is plausible that correcting a documented deficiency is helpful, while indiscriminate intake of supplements in the absence of a deficit is not robustly supported in the literature. Uncertainties remain regarding the optimal cutoff for ferritin and how individual variability, clinical forms of alopecia, and concomitant factors (e.g., medications, stress, diseases) modulate the nutrient-hair relationship.

Why vitamins and minerals matter for hair

The hair follicle is one of the organs with the highest cellular turnover in the body: hair growth requires energy, proteins, and enzymatic cofactors. Various micronutrients are involved in the cellular processes of the follicle and in keratin synthesis. Recent scientific reviews indicate that iron, vitamin D, zinc, and some B vitamins are among the most studied in relation to hair loss, especially in diffuse forms such as telogen effluvium and in some autoimmune conditions like alopecia areata [1].

Which nutrients are most frequently investigated?

Among the most evaluated micronutrients are:- Iron (often measured as ferritin) because anemia and reduced iron reserves can affect the follicular cycle;- Vitamin D, for its role in cell differentiation and immunomodulation of follicles;- Zinc, involved in protein synthesis and cell repair;- Biotin (vitamin B7), known for its role in the health of rapidly growing tissues. Reviews consolidate the multitude of studies observing associations but call for more robust controlled clinical trials to establish clear causal effects [1].

Plausible biological mechanisms

Multiple mechanisms have been proposed: iron deficiency can alter the proliferation of follicular matrix cells; vitamin D appears to influence the hair cycle and local immune response; zinc acts as an enzymatic cofactor in protein synthesis and antioxidant defense. These explanations are biochemically plausible, but clinical translation (i.e., whether supplementation produces measurable improvements in all patients) depends on dose, duration, and whether a documented deficiency exists [3].

How to assess deficiencies: tests and interpretation

Not all laboratory tests are equally useful for explaining hair loss. For tests to be informative, they must be examined in the clinical context (age, menstrual cycle, diet, medications, systemic signs). Reviews indicate ferritin and 25-OH-vitamin D among the most frequently altered tests in patients with diffuse hair loss; however, there is no single universally accepted threshold to define deficiency in relation to hair [1].

Ferritin: what value to consider?

Ferritin is the marker used to estimate iron reserves. Observational studies show lower average values in groups with telogen effluvium compared to controls, but recommended cutoffs vary between studies. An analysis of a large sample evaluated the diagnostic capacity of ferritin to distinguish cases of telogen effluvium and proposed thresholds that require clinical interpretation along with other blood tests [6].

Vitamin D and other tests

25-OH-vitamin D is often low in patients with alopecia areata and in some with diffuse hair loss; observed differences in the literature suggest associations, but therapeutic interventions with vitamin D show variable results depending on the modality (topical, intralesional, or oral) and the clinical picture [2][3]. For zinc, biotin, and B vitamins, the data are less homogeneous: in the presence of documented deficiency, correction is indicated, while the routine use of tests and supplements in the absence of clinical suspicion is less supported [5][4].

What the research says about supplements and nutritional interventions

The available literature includes observational studies, small controlled studies, and some reviews. An extensive review on vitamins and minerals concludes that the evidence is fragmented: associations exist between some low blood levels and hair loss, but proof that systematic supplementation improves outcomes in non-deficient subjects is limited [1]. A retrospective study on patients with alopecia and laboratory abnormalities did not show a clear effect of supplementation on hair density in overall analyses, while noting individual cases that may benefit from documented deficit correction [7].

Biotin: when is it useful?

Biotin is often found in commercial hair products. Systematic reviews indicate that evidence supporting the use of biotin in people without a specific deficiency is scarce; the most solid benefits are observed in cases of confirmed deficiency or in rare conditions (e.g., congenital biotinidase deficiency) [4]. High-dose use can also interfere with some laboratory tests.

Combined supplements and clinical studies

Some combined formulations (nutraceuticals with amino acids, plant sterols, vitamins, and minerals) have been studied in controlled trials: results show occasional improvements in density or thickness, but the quality of the studies is variable and generalizability remains limited. In the absence of deficiency, current guidelines advise caution and prefer targeted correction over empirical intake [7].

What this means in practice

For those experiencing diffuse hair loss, the first practical indication is an accurate clinical evaluation: the doctor or dermatologist will assess medical history, medications, triggering events (e.g., fever, childbirth, surgery, weight loss), and skin signs. First-level tests usually include ferritin, 25-OH-vitamin D, complete blood count, and, if indicated, TSH and B vitamins. A targeted approach to documented deficiencies is supported by literature; however, the general and unevaluated use of supplements has limited evidence and can be useless or potentially harmful.

Practical advice for the public

- Do not start high-dose supplements without tests: correcting a documented deficiency is reasonable. [6][7]- A varied and balanced diet often makes supplementation unnecessary in healthy individuals; those following restrictive diets or with specific medical conditions need checks. [1]- In case of drug therapy, consult your doctor: some supplements can interfere with laboratory tests or medications.- Hair fiber care (reducing thermal/mechanical stress) and stress and sleep management are complementary measures, not alternatives to clinical evaluation.

Key points to remember

• Hair loss can have many causes; nutrients are only one of the possible components.
• Correcting a documented deficiency (iron, vitamin D, zinc, or biotin) can be helpful in individual patients, but does not always guarantee complete regrowth.
• There is no solid evidence that indiscriminate intake of supplements improves hair in people with normal values.
• Interpreting tests requires clinical context: threshold values vary between studies and populations.
• For safety and efficacy, always act under medical supervision when using supplementation for therapeutic purposes.

Limitations of evidence

It is important to distinguish between types of studies: observational studies show associations between low nutrient levels and hair loss, but do not in themselves prove causality. Many studies are small, with variable diagnostic criteria and without randomized control of supplementation, which limits the interpretation of effects. Furthermore, the variability of thresholds (e.g., for ferritin) and measurement techniques complicates direct comparisons. To move from biological plausibility to causal evidence, well-designed clinical trials are needed, with defined populations and standardized clinical endpoints. In the meantime, interpretive caution remains necessary [1][5][6].

Editorial Conclusion

Current science confirms that vitamins and minerals are necessary for hair health and that, in the presence of documented deficiencies, correction is a reasonable strategy. However, there is no nutritional panacea that solves all cases of hair loss: loss can depend on genetic, hormonal, metabolic, pharmacological factors, and lifestyle. A structured clinical approach — medical evaluation, targeted tests, correction of deficiencies when present, and measures for hair fiber and scalp care — is the most consistent path with available evidence. Working with healthcare professionals avoids waste, risks of overdose, and missed diagnoses of underlying conditions.

Editorial Note

This article has been updated to reflect the latest scientific knowledge. The aim is to inform the reader clearly and reliably; it is not intended to replace individual clinical evaluation. For specific questions or to start a diagnostic-therapeutic path, consult your doctor or trusted dermatologist.

SCIENTIFIC RESEARCH

1. Almohanna, H. M., Ahmed, A. A., Tsatalis, J. P., & Tosti, A. The role of vitamins and minerals in hair loss: a review. Dermatology and Therapy (Heidelb). 2019;9:51–70. https://doi.org/10.1007/s13555-018-0278-6
2. Hussein KA et al. Vitamin D deficiency in patients with alopecia areata: a systematic review and meta‑analysis. J Am Acad Dermatol. 2018 (meta‑analysis). https://doi.org/10.1016/j.jaad.2017.07.051
3. Gerkowicz A., Chyl‑Surdacka K., Krasowska D. The role of vitamin D in non‑scarring alopecia. Int J Mol Sci. 2017;18(12):2653. https://doi.org/10.3390/ijms18122653
4. Patel D.P., Swink S.M., Castelo‑Soccio L. A review of the use of biotin for hair loss. Skin Appendage Disord. 2017;3(3):166–169. https://doi.org/10.1159/000462981
5. Meta‑analysis: Changes of serum trace elements level in patients with alopecia areata: a meta‑analysis. J Dermatol. (meta‑analysis on zinc/selenium). 2017. https://doi.org/10.1111/1346-8138.13705
6. Elbasiouny S. K. et al. The Diagnostic Value of Serum Ferritin for Telogen Effluvium: a Cross‑Sectional Comparative Study. Clin Cosmet Investig Dermatol. 2021; DOI: 10.2147/CCID.S291170. https://doi.org/10.2147/CCID.S291170
7. Klein EJ, Karim M, Li X, Adhikari S, Shapiro J, Lo Sicco K. Supplementation and hair growth: a retrospective chart review of patients with alopecia and laboratory abnormalities. J Dtsch Dermatol Ges (JDIN/JAAD Int. 2022). https://doi.org/10.1016/j.jdin.2022.08.013
8. Karakoyun Ö., Ayhan E., Yıldız İ. Retrospective review of 2851 female patients with telogen effluvium: a single‑center experience. J Cosmet Dermatol. 2025;24(2):e70037. https://doi.org/10.1111/jocd.70037