Expensive supplements promising to provide younger, firmer and glowing skin could be a waste of money, according to a new study.
Scientists at the British Nutrition Foundation (BNF) found that a balanced diet, sunscreen and not smoking were more likely to protect skin than the craze for "neutraceuticals".
The global beauty supplements market is expected to reach $7.1bn by 2023, with many containing vitamins A, C, B2, B3, B7, and the minerals iodine and zinc.
Although these supplements are beneficial, BNF scientists said there was little evidence that added exotic ingredients such as green tea or pomegranate extract, fish oil, collagen and co-enzyme Q10 had any effect.
The BNF found these ingredients could be beneficial as part of a healthy diet, but there was only limited evidence that they contained any benefit when they were used in supplements.
In the review Nutraceuticals And Skin Appearance: Is There Any Evidence To Support This Growing Trend? the BNF said some results from lab experiments suggested these ingredients could have antioxidant, anti-inflammatory or collagen enhancing effects.
But it said it could not be assumed that these results would be relevant beyond studies on skin cells in a dish.
The BNF was only able to identify a few well-conducted human trials, and said the findings of these were inconsistent.
It concluded that a healthy diet and lifestyle was much more likely to provide the effects consumers hoped to gain from skin supplements.
Ayela Spiro, nutrition science manager at the British Nutrition Foundation, said: "As consumers can spend hundreds of pounds a year on oral beauty supplements, we felt it was important to investigate the association between the ingredients in these products, and the signs that we associate with skin ageing, such as wrinkles, loss of elasticity and moisture.
"While there is a body of research on the science of skin ageing, evidence for the benefit of nutraceuticals to skin appearance is currently not strong enough to draw firm conclusions."