If you've ever mixed some liquid highlighter into your base or boosted your moisturizer with a few drops of face oil, welcome to our club: We love a bit of freewheeling, product-enhancing skin cocktailing in the Cosmopolitan beauty department. But it's possible to take things too far, as evidenced by an innocent exchange between two Cosmo colleagues that went as follows:
"Do you like this sunscreen?"
"Yes! It's not too heavy and it mixes really well with my foundation."
This made me choke on my lunch, and actually shout "No!" across the office. First of all, points to my colleague for even entertaining the thought of daily facial sunscreen, and making a valiant effort to incorporate it into her routine in a way that makes it quick and easy to stick with. As any skincare expert and beauty journalist will tell you in any skincare feature you've ever read, sunscreen is your number one face-saver, halting the signs of aging (which include lifeless skin, pigment blotches and crow’s feet) in their tracks—or before they even start. If you don't use a broad-spectrum (meaning it deflects UVA and UVB) sunscreen all year round, either in your moisturizer or as a separate UV protectant, you're basically wasting your money on your line-plumping or pigmentation-busting serums, as the UV damage will just cancel out their effects.
But here's the thing: You have to apply it properly to get the protection promised on the tube (SPF30 or 50 is best; don't go under 20 no matter how dark your skin is). That means it should be the last skincare product you put on before your foundation and/or other makeup. It also means applying the right dose, which is 1.25ml for the face: that's a quarter of a teaspoon, or a blob the size of a 10-peso coin.
And, importantly, "never, ever adulterate sunscreen by mixing it with other products," says dermatologist Dr. Sam Bunting. "Like medicine, you will hamper and dilute its effectiveness when you tinker with it, and sunscreen is too important to risk that." Lest you'd forgotten: apart from ruining your glowy looks, UV rays also cause pesky skin cancer.
Now, I hear you ask, with so many foundations boasting a high SPF these days, can't that just serve as my sun protection? Unfortunately, the expert verdict is a resounding NO. "I never recommend it," says Bunting. "Foundation should be applied just where needed for a 'real skin but better look,' whereas sunscreen must cover the entire skin generously and evenly in order to give every inch proper protection. If you tried that with foundation, you'd end up with a mask-like appearance." If you're thinking "Hell, that's how I use foundation," you're still not off the hook. "Foundations rarely have adequate UVA (the rays that age skin and cause DNA damage) protection, unlike good dedicated facial sunscreens, which effectively deflect or absorb both UVB (the burning rays) and UVA."
The holy grail for most people is a facial sunscreen that's not too oily, so you can use it on top of other skincare and even on oily skin without feeling like you've basted your face in lard. It will also double as a primer, so you can do away with that extra layer. We’ve lined up some of our favorites right here.
This article originally appeared on Cosmopolitan.com/uk. Minor edits have been made by the Cosmo.ph editors.