Fingernail strength -- like hair thickness, skin tone, and shoe size -- is subject to normal variation. Weak, brittle nails are most commonly caused by excess exposure to water, but may also be a consequence of certain disease states and severe malnutrition. While vitamins are essential for normal growth and function, most vitamin supplements are unlikely to help strengthen your nails. However, there are other steps you can take to improve nail health.
Causes of Weak Nails
Although a common cause of brittle and weak nails is repeated exposure to water, fingernails can reflect a general state of health, according to the American Academy of Dermatology. A well balanced diet that includes all essential nutrients, including vitamins, is important for the growth, development, and maintenance of all body tissues -- including the formation of a the keratin found in nails and hair. Keratin is made of protein, and also contains components such as sulfur and minerals including magnesium, calcium, iron, zinc, sodium and copper, according to a review in the July-August 2010 issue of "Clinics in Dermatology." Any condition or severe nutrient deficiency that affects the formation of keratin can impact nail strength.
Many supplements are sold with the promise of strengthening nails, but the available scientific research doesn't back up most of those claims. A review of research on vitamins and nail strength, published in the August 2007 issue of "The Journal of Drugs in Dermatology," found no evidence to support the use of vitamin C, vitamin E, vitamin B12, or vitamin A and related compounds in improving nail health. These researchers also found no link between the use of zinc, iron, copper or selenium and nail health. An exception was the use of biotin, a vitamin which appeared to help in some cases of brittle nail syndrome.
Biotin, sometimes referred to as vitamin H, is commonly recommended to strengthen nails, but the evidence supporting this claim is based on older, small studies. One study of 44 people, published in the April 1993 issue of "Cutis," reported a 25 percent increase in nail plate thickness in 63 percent of participants who received biotin supplements. Another study of 32 people, published in the December 1990 issue of "Journal of the American Academy of Dermatology" reported similar benefits, but found that biotin was not equally effective in all study participants.
The Adequate Intake of biotin is 30 mcg for adults -- a much smaller amount than the 1 to 3 mg dose used in these studies. However, available research suggests these doses do not pose a safety risk, according to the Institute of Medicine of the National Academies. Larger studies are needed to determine if biotin produces benefits in healthy, well-nourished individuals who do not already have brittle nails, or if improvements will be noted in nails affected by a health condition.
Tips for Strong Nails
The American College of Osteopathic Dermatology offers these tips to prevent nails from becoming brittle, split or overly soft:
- Avoid getting hands repeatedly wet and dry by wearing gloves when doing housework, such as washing dishes.
- Use lotion containing lanolin if dryness is a problem.
- If overly soft nails are the problem, limit exposure to household cleaners, nail polish removers and other household chemicals, as these substances can weaken nails.
- Be gentle with your nails to prevent additional breaking or splitting.
If you have unusually soft or brittle nails, see your doctor for advice. In addition to nail damage caused from excessive water or chemical exposure, certain health problems such as anemia, diabetes, or heart, liver, kidney and lung disease can also cause discoloration, weakening or changes to the thickness of the nail structure. Getting the appropriate diagnosis is key to knowing how to treat your problem nails, so it's wise to see your doctor before taking biotin or any other supplement.
Reviewed by Kay Peck, MPH, RD