Though we often don't think much about it, hair provides us with some protection from the sun. Where your hair is fairly thick, it is very effective in blocking the sun's rays. As a result, you usually don't tan in areas where you have a significant amount of hair.

When people shave their heads for the first time, this effect is often visible. Especially in summer, the scalp will look paler than the rest of your skin initially. Given some regular exposure to the sun, your scalp will tan normally and will soon match the colour of the rest of your exposed body. For most people, it is probably a matter of a week or two.

Some people can't wait that long, though. Perhaps they find the appearance of a pale scalp embarrassing, or perhaps they're about to have photos taken, and don't want the paleness immortalized. For such people, a 'sunless' tanning product might be appropriate.

Probably the best choice for most people who want a self-tan are the many tanning lotions on the market. Effective tanning lotions contain dihydroxyacetone (DHA), a colourless sugar which reacts with the dead skin cells on the outer layer of your skin to cause a colour change. Dead skin cells slough off fairly regularly (in slightly more than a month, your skin has re-grown itself completely), so the tan will only last a few days to a week. Once it starts fading, you'll need to re-apply the tanning lotion to maintain the look.

All the tanning lotion does is change the colour of dead skin cells. As such, your newly 'tanned' skin will not protect you from the sun's rays the way melanin (from a real tan) would. It is therefore important to continue to protect yourself from the sun, or you'll get a real burn to go with your fake tan.

Sunless tanning lotions are considered safe for the skin, and I haven't read about any dangers associated with them. In fact, they're probably safer than getting a real tan, since regular exposure to ultraviolet radiation results in a high risk of skin cancer. Even if you don't get skin cancer, sun damage will make you look older significantly faster than you should. Remember, wear sunscreen.

After a week or two with a tan-in-a-bottle, the skin tone of your scalp will probably have caught up with the rest of your skin, and you won't need tanning lotion for your skin to be an even colour.

Related Links

Sunless.com - An excellent site, filled with reviews, advice, and message boards. It looks very thorough, and should probably be your first stop if you're looking to pick out a good product or trying to find out how to do it right.

Sunless tanning [yestheyrefake.net] - A good look at one person's experience with sunless tanning, filled with suggestions and comments.

How do sunless tanning products work? [chemistry.about.com] - A brief article explaining some of the hows and whys of self-tanning.