We spend millions on supplements every year but when it comes to hair, skin and nails do they really work? Dr Hannah Sweilam finds out.

Let’s talk about hair, skin and nail supplements. We’ve seen adverts that claim these supplements can promote healthy hair, glowing skin and strong nails, but is there scientific evidence to support these claims?

Often these claims centre around the vitamin ‘biotin’ which is commonly included in these supplements and marketed as a go-to vitamin for beauty.  Biotin is a B vitamin- also known as vitamin B7- and in common with other B vitamins, it helps the body to release energy from food.

Biotin deficiency is rare, but when it does occur, symptoms include hair loss and thinning, depression, exhaustion and muscle weakness.  The reason biotin deficiency is rare it that it is found in a wide range of foods, and the bacteria in our gut produce it too.  Good sources of biotin include eggs (in particular, the yolk), salmon, sardines, nuts, whole grains and bananas.

Can supplements help hair?

As you might expect, if someone has hair loss or thinning due to biotin deficiency, biotin-containing supplements will likely be effective in promoting hair growth.  On the other hand, there is no good evidence to support claims that biotin makes hair grow faster or thicker in non-biotin deficient individuals.

There is a study that appears, at first glance, to demonstrate the effectiveness of a biotin-containing supplement in promoting hair growth.  This study (sponsored by the manufacturer) reports that the supplement successfully increased hair thickness in women with thinning hair.  For one thing, this study is too small for the results to be convincing (15 participants) and secondly, the participants may have been biotin deficient which would make them unrepresentative of the general population and distort the results.

Zinc deficiency can cause hair loss and zinc is often found in beauty supplements.  There is no evidence that zinc supplementation is of any benefit to someone who is not zinc deficient.  Only small amounts of zinc are required by the body and it is considered unsafe to consume increased amounts of zinc for extended periods as this can cause anaemia and weakened bones.  Meat, shellfish, dairy foods, bread, pulses and cereals are good sources of zinc and most people get enough zinc from eating a healthy diet.  

Hair strength and thickness are largely determined by our genes. Hair that is naturally thin or weak, and that has already reached it’s full potential, is unlikely to be improved by supplements.  When it comes to actual hair loss, it is best to determine the underlying cause rather than try to treat indiscriminately with supplements.  For example, hair loss that is due to a hormonal imbalance will not improve until that hormonal imbalance is addressed.

Can Supplements help nails?

Thin, brittle nails are a common problem, particularly among women.   Brittle nails are often due to frequent contact with water or chemicals such as detergents and nail polish, or may be a sign of ageing.  Less commonly, they’re a result of an internal imbalance, such as a thyroid problem, or a nutritional deficiency, such as iron deficiency.

Supplement manufacturers commonly market biotin for nail health based on two small-scale studies published in the 1990s.  One of these found that most of it’s participants (22 out of 35) had thicker nails within six months of starting a biotin supplement.  The other reported that 41 out of 45 participants had harder nails after taking 2.5mg of biotin every day for approximately five months. Both these studies were small, and there were no control groups, so improvements could have been due to other factors such as changes to diet.  Biotin might increase the thickness of nails in people with brittle nails but more research is needed.

In terms of other nutrients that may be included in supplements to promote nail growth,  there is no evidence that vitamins A, B12, C, E, or zinc, iron, copper or selenium improve the nail health of well-nourished people who are not deficient in these vitamins.

Wearing gloves while doing work where your hands are exposed to water, regularly applying a good moisturising cream, and limiting use of nail polish will help maintain nail health.  It is important to seek medical advice if your nails have changed in colour, texture, shape or thickness in order to identify any underlying cause.

Can supplements help skin?

The antioxidant properties of vitamin C and its role in collagen production are well known and for that reason, it is often included in beauty supplements with the promise that it will promote healthy skin.  Yet the recommended daily amount of vitamin C is easily obtained from a balanced diet and there is no evidence that taking supplements to exceed this amount will provide any benefit.  In fact, it has been shown that high doses of vitamin C in supplements can increase oxidation in the body rather than reduce it, whereas vitamin C obtained directly from food does not show this trait.  This suggests that vitamin C supplements could do more harm than good where a person already consumes an adequate amount of vitamin C through their diet.

Selenium frequently makes an appearance in beauty supplements. It is an antioxidant mineral which plays an important role in preventing cell damage. Selenium is only required in small amounts and deficiency is uncommon.  Good sources are vegetables, brazil nuts, fish, meat, eggs, liver, and garlic.  A study published in the Lancet recommends that people who are not selenium deficient should steer clear of selenium supplements as they are unlikely to gain any benefit from them and may suffer unwanted effects.  Unwanted effects include an increased risk of type-2 diabetes.  The large SU.VI.MAX study found that supplements containing selenium, vitamins C and E, and zinc increased the risk of skin cancer in women.

The final word…

In the case of someone who is well-nourished, claims that a supplement will make hair grow thicker of faster, or will benefit skin, are unfounded.  It is possible that biotin might increase nail thickness in people with brittle nails though the evidence is preliminary.  It is becoming increasingly apparent that isolating specific nutrients in supplement form does not provide the same health benefits as obtaining these nutrients from whole foods, and that exceeding recommended daily amounts of nutrients through supplementation is associated with risks.  All of this means that the savviest way to nourish your hair, skin and nails is- you guessed it- by means of a balanced diet rather than supplements.