By Steven Gabel, MD, FACS – Gabel Hair Restoration Center, Portland, Oregon
Understanding how nutrition affects hair health is essential, especially for individuals experiencing increased shedding without an obvious medical cause. One of the most influential papers on this topic is Rushton’s comprehensive review, Nutritional Factors and Hair Loss. This publication remains a cornerstone in understanding which dietary factors truly impact hair biology and which popular beliefs lack scientific support.
Why This Paper Is Important
Many assumptions about nutrition and hair loss stem from anecdotal reports or advertising rather than controlled studies. Rushton’s work is valuable because it evaluates the evidence objectively and focuses on otherwise healthy individuals—those who are not malnourished or suffering from systemic illness. The review also makes a critical distinction: some nutritional factors affect the hair follicle itself, while others influence the scalp skin, which in turn can contribute to shedding.
Iron Deficiency: The Most Significant Factor Identified
Among all nutrients reviewed, iron—measured through a blood test called serum ferritin, which reflects iron stores—shows the strongest association with persistent shedding. Rushton reports that:
- 65% of women with chronic telogen effluvium (CTE)—a condition defined as hair shedding lasting more than six months—had ferritin levels below 40 µg/L.
- 96% had ferritin levels below 70 µg/L, a level considered necessary for healthy hair cycling, according to Rushton.
These findings demonstrate that iron deficiency can quietly disrupt the hair growth cycle even when routine blood counts appear normal. Improving ferritin levels has been shown to reduce the proportion of hairs entering the shedding (telogen) phase.
L-Lysine: An Essential Amino Acid With a Meaningful Role
Another important contribution of Rushton’s paper is the discussion of L-lysine, an essential amino acid found in foods such as meat, eggs, and fish. The review highlights that some individuals with low ferritin do not respond adequately to iron alone. When L-lysine was added to iron therapy:
- Ferritin levels increased more effectively
- Hair shedding decreased by nearly 40% over six months
Although the exact mechanism is still being studied, L-lysine appears to support iron absorption or utilization and should be considered when dietary protein intake is limited.
Zinc, Biotin, and Other Supplements: Limited Evidence of Benefit
Zinc and biotin are frequently marketed for hair growth, yet Rushton’s review shows very limited evidence supporting their use for common hair-shedding conditions. True zinc deficiency was extremely rare, and correcting it did not improve CTE. Biotin deficiency is also uncommon in individuals with balanced diets, meaning supplementation is usually unnecessary.
Equally important, the paper warns that excess supplementation can worsen shedding. Fat-soluble vitamins such as vitamin A, as well as high-dose multivitamins, may create metabolic imbalances or interfere with iron absorption.
A Measured Approach to Nutrition and Hair Health
The primary message of this review is that nutrition matters, but only certain nutrients have strong, reproducible evidence linking them to hair loss. Those include:
- Iron (serum ferritin), ideally ≥70 µg/L
- L-lysine, particularly when ferritin is low or difficult to raise
Other popular supplements lack convincing evidence and may cause harm when taken unnecessarily.
Conclusion
Nutrition is not the sole driver of hair loss, but it is an essential part of the overall picture. Hair follicles are among the most metabolically active structures in the body, and they rely on a steady supply of vitamins, minerals, amino acids, and energy to function properly. When nutritional intake is unbalanced—whether through deficiencies, restrictive diets, impaired absorption, or excessive supplementation—the hair cycle can be disrupted, leading to increased shedding, reduced density, or poor-quality regrowth.
It is also important to recognize that nutritional factors rarely act in isolation. They often intersect with genetics, hormonal influences, aging, stress, medical conditions, and scalp health. For many individuals, addressing nutritional status is one meaningful component of a broader, multifactorial approach to treating hair loss. Ensuring adequate iron stores, supporting protein intake, and avoiding unnecessary supplements are practical steps that help reduce the physiological stress placed on the hair follicle.
While nutrition alone cannot solve every form of hair loss, it remains an important foundation for maintaining healthy hair and optimizing the results of both medical and surgical hair restoration therapies. Taking a thoughtful, evidence-based approach ensures that patients receive safe, effective, and rational care—one that respects the complexity of hair biology and avoids the misconceptions often promoted in popular media.
Support Your Hair Health With a Professional Evaluation
If you’re experiencing increased shedding or want a personalized evaluation of how nutrition may be affecting your hair health, the Gabel Hair Restoration Center is here to help. Dr. Gabel provides comprehensive assessments and evidence-based treatment plans tailored to your individual needs. To schedule a consultation or learn more about the most effective, science-backed options for hair loss, contact us today.
Reference
Rushton DH. Nutritional factors and hair loss. Clin Exp Dermatol. 2002 Jul;27(5):396-404. doi: 10.1046/j.1365-2230.2002.01076.x. PMID: 12190640.
