Saranya Wyles, M.D., Ph.D.

But really, your sunscreen has an expiration date or time of two hours.

And this is regardless of whether it's a cloudy day, a sunny day.

You really want to make sure you're reapplying that sunscreen every two hours.

There's a lot of different ways that you can do that.

I know a lot of my male patients don't prefer to feel like they have something thick or heavy on.

They usually equate having sunscreen as...

well, if I'm golfing or if I'm out at the beach or if I'm doing an outdoor activity or hiking, I can put sunscreen on, but not as a daily habit of I'm doing this on my way to work because most of us get a lot of sun exposure actually just in the car ride to and back from work.

So I'd put sunscreen right at the very top as the number one thing you could be doing.

And then I really wanted to highlight how the skin works.

So to understand what to apply for the skin, we have to understand that the skin has its own circadian rhythm.

So the skin functions differently during the daytime than it does at nighttime.

So the skin during the daytime, it's a barrier.

It's a defense system.

This is why your AM routine should really include products like sunscreens and antioxidants.

So you really want to include vitamin C and other antioxidants that are really rich in being able to prevent oxidative stress or free radical damage from getting UV exposure, pollution exposure, etc.

So I would highlight the importance of vitamin C and antioxidants in the morning.

And then at nighttime...

your skin circadian rhythm switches.

So it goes into a more repair.

So it's just endured all the stress during the day and now it flips into repair mode where it gets rid of toxins and it starts to rebuild and repair.