Janelle says…Hi Beauty Brains! Let me start off my expressing how much I love your website! It’s informative, interesting, and best of all…SCIENTIFIC!! I am a college student, and love the last point! My question is, does Vaseline darken lips? I’ve always used it on my lips before I go to bed, but my roommate tells me that it darkens lips because it can be used to get a greater tan – as it is like an oil. Many people are adding their own anecdotal evidence about how it has darkened their lips – but I don’t know what to think! As it is, I have moderately dark lips. Is there any scientific proof? Please help! And many thanks!
The Right Brain responds:
Thanks for the kind words, Janelle! Vaseline is essentially petrolatum (which is closely related to mineral oil) so it’s reasonable to assume that they might work the same way. But we were surprised to find very little research on the effect of tanning oils on skin. (We did find studies on tanning accelerators like L-tyrosine but that’s a story for another day…) Still, after much searching, we did find one reputable source that should definitively answer your question.
Everyone seems to know that rubbing baby oil (aka mineral oil) on your skin will make you tan faster and deeper. Many articles claim that mineral oil “attracts” UV rays. But WHY is that? What’s really happening? According to a paper we found in the Journal of the American Academy of Dermatology, mineral oil (and similar lubricants) are used to in the photo-therapy treatment of psoriasis to enhance the effects of UVB treatment. Apparently the mineral oil smooths scaly skin and decreases the amount of UV radiation that is reflected. Less reflection means skin absorbs MORE UVB rays. And since UVB rays are responsible for tanning, the skin gets darker. That must be how tanning oils work!
Remember, though, that your lips don’t tan. So if you’re asking about the actual lips themselves, this won’t work. But, if you’re asking about the skin of your upper lip, yes, it is very possible that putting Vaseline petroleum jelly on it will make it get darker (after exposure to sun.)