Dr. Shereene Idriss breaks down what sunscreen actually does: broad-spectrum protects against both UVA (which breaks down collagen) and UVB (which causes sunburn). SPF 30 means you can stay in the sun roughly 30 times longer without burning. Most people don't reapply enough, especially after swimming or sweating.
What SPF should you wear every day and how often do you need to reapply?
When we're looking for an spf, we need to make sure that our SPF has broad spectrum on it.
Broad spectrum, so that
it's protecting against both UVA and uvb, because both contribute to skin cancer. One causes more burn, like uvb. One contributes more to the breakdown of your collagen, like uva. But if you're just getting a simple sunscreen, spf, not broad spectrum, you're not protecting against uva.
Oh,
so broad spectrum is not a nice to have. It's a need to have SPF 30. People don't really know. It's just a number.
Should I guess what do you think it is? Yeah, I kind of believed that, like, the 15 is only going so deep in terms of the barrier. The 30s may be going a little deep. Is it actually about the number of minutes that it's helping? Yes,
it is. It's minutes. So it roughly means how much longer you can stay out of the sun without burning compared to no sunscreen. So let's say
this is a lot of math.
Takes 10 minutes for you to burn. With an SPF of 30, it should technically take you 300 minutes. That's what SPF stands for. And so it's something that most people don't even know.
