Biotin, also known as vitamin B7 or vitamin H, pops up in every supplement marketed for strengthening hair and nails. Do biotin supplements actually work for brittle nails?

The answer is – it depends. Gah! Read on for the gory details…

Are you getting enough biotin in your diet?

Nutritional supplements generally only make a difference if you’re not getting enough of that nutrient normally, and biotin seems to play by this rule.

The daily recommended intake of biotin for adults is 30 μg/day, and a Western diet generally contains enough biotin. You can find biotin in leafy green vegetables, nuts (peanuts and almonds in particular), avocados, corn, cooked eggs, liver, salmon and meat. Some intestinal bacteria make biotin, which could also contribute to your overall consumption.

Some factors can decrease your biotin though. Biotin seems to be lower with high alcohol consumption, smoking, gastric acid disorders, in burn patients, epileptics, athletes, the elderly and with some inborn genetic disorders. Pregancy and breastfeeding also decrease biotin.

Eating uncooked egg whites can also decrease biotin, even though cooked eggs are a good source! Raw egg white contains a protein called avidin which binds tightly to biotin, preventing it from working. Cooking the egg destroys the avidin.

How can I tell if I have a biotin deficiency?

As well as thin nails that are brittle and break easily, other signs of biotin deficiency are:

• hair loss
• conjunctivitis (eye infections)
• a red scaly rash around on face and genitals
• neurological problems such as depression, lethargy, numbness and tingling

What’s the evidence that biotin works?

There have been a few clinical studies on the effect of biotin supplements on brittle nails. In these studies. 2.5 mg were taken each day for several months, and about two-thirds of women had improved nails (thicker, harder, less splitting).

It’s worth noting that about 1/3 of women in these trials saw no effect. This is why it’s thought that you need to have a biotin deficiency to see any improvement with biotin supplements. If your brittle nails aren’t due to a biotin deficiency – for example, if your nails are brittle from using acrylics – then it’s unlikely to have much of an effect.

Are there any side effects of biotin?

Luckily, there’s almost no risk of overdose with biotin, unlike with many common supplements, so it’s quite safe in that regard. However, some people who take biotin supplements have found that they’re more prone to acne breakouts. It’s been suggested that this is due to the extra biotin blocking the absorption of pantothenic acid (vitamin B5), which could cause acne.

Verdict

The best way to get biotin into your system is through food, but if you have brittle nails and you think you might have a biotin deficiency, taking a biotin supplement (2.5 mg/day) could help. Record the condition of your nails regularly while you take the supplement to check if it’s having any effect, and if you get acne breakouts, you may want to stop taking it.

References

LG Hochman, RK Scher & MS Meyerson, Brittle nails: response to daily biotin supplementation, Cutis 1993,51, 303-305.

GL Floersheim, [Treatment of brittle fingernails with biotin], Z Hautkr 1989, 64, 41-48.

VE Colombo, F Gerber, M Bronhofer & GL Floersheim, Treatment of brittle fingernails and onychoschizia with biotin: scanning electron microscopy, J Am Acad Dermatol 1990, 23, 1127-1132.

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