Optics

Hey, just had a quick question for any scientists about “tanning oil.” I’ve had people tell me that there exists an oil that, when applied, causes a person to get more suntan than they would have otherwise. I take this to mean that more energy will reach the skin. I can’t seem to make sense of it physically. Wouldn’t an oil cause some or no reflection and thus decrease or not change total energy transfer? I thought the result might be due to thin-film diffraction, but conservation of energy must hold in the system. I suspect that there’s some biological factor that I’m missing. Any thoughts?

Wrong site for this question?

Or less energy will be reflected, maybe?

Honestly, I don’t know how, or if, such things work. I was under the impression they were more in the nature of products that allowed you to tan without burning, rather than actively facilitating tanning.

PSquared,
there are suntanning oils out there that tan you even without any sun. How they work is beyong me. My guess would be that they enhance pigment growth.

What’s your take?