When we eat foods containing beta carotene the body converts it into Vitamin A (Retinol).
Retinol - now widely marketed in anti-wrinkle creams - stimulates skin cell growth and builds collagen, which is essential to help maintain the skin's elasticity.
The theory is that because this algae is found on sea shores it contains a natural enzyme to protect it from the sun, which the body can also use to help boost the production of melanin.
Makers claim this allows you to tan more quickly and so limit your time in the sun - therefore doing your body less damage.
Again, this product is often aimed at people with sensitive skin as manufacturers claim it allows users to spend less time in the sun.
They also warned that pregnant women should not take beta carotene as too much vitamin A can harm an unborn baby.Tyrosine is an amino acid which helps the body produce melanin - the pigment produced by the skin to protect us from the damaging effects of sunlight. The theory is that if taken for a period before you go into the sun these pills will allow your body to be better able to produce melanin and so you will tan more easily.Makers claim you can therefore get the same amount of tan with less exposure to the sun - so causing less damage to your skin.The verdict Professor Hawk said: 'This is sometimes used in sunscreen and when applied as a sun cream can prevent sunburn.But there is no evidence that it affects your tan in any way.'Himanthalla elongata The claims This algae is said to promote the production of melanin.