Self-Tanner (Sun Care)

Self-tanner colors skin without any ultraviolet involved. The active is dihydroxyacetone, a simple sugar known as DHA, and it reacts with amino acids in the dead cells of the outermost skin layer to form brown pigments. Color starts appearing in two to four hours, reaches full depth within about 24, and fades over five to seven days as those cells shed naturally. Say the important part plainly: this offers no protection from the sun at all.

Format decides the difficulty more than the formula does. Mousses carry a guide color so you can see where you have been. This makes them the most forgiving to apply and the messiest on towels. Lotions build gradually across several days at low DHA levels, so mistakes stay small. Water and drop formats mix into your own moisturizer and develop overnight with no guide color, which suits confident hands. Spray booths and aerosols cover fastest, though DHA is approved for external use only, so eyes, lips and any surface you could inhale through stay out of it.

After-Sun sits at the opposite end of the same shelf, treating the consequences of real sun. Body Lotion from the Bath and Body guide is what keeps a finished tan even as it fades. Bronzer in the Makeup guide does the same job for a single evening and washes off.

Anyone who wants color without exposure belongs here, and that is the case for the whole category. It also evens out the look of legs before an event and covers uneven tone on the shins. Broken, sunburnt or freshly waxed skin should wait, and eczema prone skin often finds the alcohol in mousses stinging.

Prepare more than you apply. Exfoliate 24 hours ahead and shave 24 hours ahead, moisturize knees, elbows, ankles and knuckles right before you start so those dry patches do not grab extra color, and use a mitt. Wash your palms immediately after each section. Let it develop for the stated hours before showering, then keep skin moisturized daily, since a tan fades exactly as fast as the dead cells carrying it come off.