Nothing. The best tanning lotion is water. It creates a reflector and that's how u get dark. In a tanning bed they will sell u all this stuff that tells u it will make u darker. Actually it doesn't. U should never put anything on ur skin that u cannot eat. It absorbs into ur body and causes all different kinds of diseases. I have never used any tanning lotion and I get too tan. I have been to dermatologist that say u shouldn't use anything... Even sunscreen. Skin cancer is growing in the US. They say the reason is from all the stuff We use to protect us. Places like Africa have NO skin cancer. Just use a spray bottle with water and call it good.
Some of the best types of tanning lotions to help you become or get dark include Brown Sugar American Princess and Hemperor Black Bronzer among others. It is not advisable to use these kinds of tanning lotions outside of the tanning bed. Check out lotionsource.com/topsellers.html for more information.