Load up on Vitamin D3. The strength coach, Charles Poliquin has given the heads up that Vitamin D3 is as important to the human body as Omega 3. So both I and my mother have followed his advice and taken his high quality Vitamin D. As a result we have both found we have tanned more quickly, without burning and the tan has lasted longer.
It has to be D3. D2 is not bio-available.
Here is a link to read more about just what good D levels can do for you: www.charlespoliquin.com