None. A tan is not a health marker. It is extra melanin after UV has already injured DNA. UVB burns the surface; UVA goes deeper and drives aging and cancer risk. Both are in daylight. Both are in tanning beds.

A base tan is a weak filter

Induced melanin is often compared to about SPF 2 to 4. The FDA sun-safety advice still starts at real clothing and sunscreen, not a pre-tan. SPF 30 in a bottle is a different object from a leftover glow.

Intentional UV for color is the risk you can skip

The AAD and IARC treat tanning lamps as carcinogens. They can run hotter than noon sun. Damage adds up: a childhood blister still counts decades later.

Vitamin D is a poor excuse for a tan. Brief incidental UV, food, or a supplement covers most people without chasing color. See how UV causes skin cancer.

Color without the lamp

DHA self-tanners stain the outer layer. They are not a UV filter—wear sunscreen over them outdoors. If you tan anyway, at least read today’s peak on the live index so you know the rate you are paying.