What vitamin deficiency causes nails to split from the nail fold?

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From the Guidelines

A vitamin B7 (biotin) deficiency is the primary vitamin deficiency that causes nails to split from the nail fold. This condition is also known as onychoschisis, and biotin supplementation has been successful in its treatment, as noted in a study published in the American Journal of Clinical Dermatology 1. Biotin plays a crucial role in keratin production, the protein that forms the structure of nails, which explains why insufficient levels can lead to brittle, splitting nails.

Key Points to Consider

  • Biotin deficiency can be caused by genetic abnormalities or malabsorption, and supplementation can help alleviate symptoms such as hair loss and brittle nails 1.
  • The recommended daily dose of biotin for nail health is 2.5-10 mg, and it may take at least 3-6 months to see improvement.
  • Other nutrients like zinc, iron, and protein also support nail health, so ensuring adequate intake through diet or supplements is essential.
  • If nail problems persist despite supplementation, it is crucial to consult a healthcare provider to rule out other conditions like fungal infections or psoriasis that may cause similar symptoms.

Additional Considerations

  • While using nail hardeners and avoiding harsh chemicals can provide temporary relief, addressing the underlying nutritional deficiency is essential for long-term improvement.
  • More research is needed to fully understand the role of biotin in nail health, but current evidence suggests that it is a critical nutrient for preventing nail splitting and other related issues 1.

From the Research

Vitamin Deficiency and Nail Health

  • The vitamin deficiency that causes nails to split from the nail fold is often associated with a lack of biotin, also known as vitamin B7 2, 3, 4.
  • Biotin plays a crucial role in maintaining nail health, and its deficiency can lead to brittle nails, characterized by nails that split, flake, and crumble 5, 2, 3, 4.
  • Studies have shown that oral supplementation with biotin can improve nail strength and reduce brittleness 2, 3, 4.
  • Other factors, such as environmental and occupational factors, nutritional deficiencies, and systemic diseases, can also contribute to nail brittleness and splitting 2, 3.
  • While biotin supplementation may be beneficial for nail health, it is essential to note that biotin can interfere with laboratory testing, and physicians should be aware of this potential interference when recommending biotin supplements 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Brittle nails.

Journal of cosmetic dermatology, 2004

Research

[Treatment of brittle fingernails with biotin].

Zeitschrift fur Hautkrankheiten, 1989

Research

Vitamins and minerals: their role in nail health and disease.

Journal of drugs in dermatology : JDD, 2007

Research

A survey-based study of physician practices regarding biotin supplementation.

The Journal of dermatological treatment, 2022

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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