TikTok’s Serum Hack Made My Makeup Look So Natural

If you wear makeup, chances are you've Googled how to prevent it looking cake-y. No matter the price tag, level of coverage, or if it was dreamed up by a world-renowned celebrity makeup artist, pretty much all foundation collects in fine lines and pores eventually. While we're no longer averse to skin texture — it's entirely normal and natural — that hasn't stopped TikTok's beauty creators from inventing new ways to apply foundation for a smooth finish that looks believable.

Not long ago, everyone was into creating custom BB cream, mixing foundation, moisturizer, and highlighter (it works, I'm totally convinced). Then came the rainbow-contouring hack, which TikTokers claimed would be the only trick you'd ever need for glowing skin all year round. Ahead of spring, when you might choose to pare back the coverage a little, it's all about being your own alchemist, combining your skin care and makeup for a natural-looking, lightweight result.

I've interviewed countless makeup artists over the years and one thing many of them agree on is that blending skin care and makeup can be a game-changer. I often give my face a spritz with a hydrating toner to help my concealer go on smoothly and I know that makeup artist Caroline Barnes likes to enhance the glow of makeup using a face oil. Recently, TikTok's beauty enthusiasts have enlisted one very specific skin-care product: polyglutamic acid serum.

Beauty pro Kylie Larsen recently went viral for mixing her foundation with The Inkey List's Polyglutamic Acid. She said, the trick is "smoothing and hydrating" and makes her skin "look like a filter," going on to explain that those with dry skin would also benefit from a squeeze of the serum while applying foundation. Like all intriguing TikTok hacks, it wasn't long before other makeup wearers decided to give it a go, like Monique (a.k.a. @skinfiltrator). Her video has also amassed thousands of views and she, too, is sold. "Came out flawless! Felt like butter," she captioned her post.

So what actually is polyglutamic acid? Essentially, it's a souped-up version of hyaluronic acid. "Polyglutamic acid, like hyaluronic acid, is a humectant that chemically attracts water molecules," dermatologist Hadley King, MD recently told R29. "It forms a hydrogel film on the surface of the skin that prevents water from evaporating," Dr. King continued. "Its occlusive property means that it helps the skin retain moisture." In other words, it keeps hydration under lock and key, which, with the cold weather still clinging on, makes it something of a skin-care savior.

Happily, polyglutamic acid isn't as under the radar as it once was, and many beauty brands are jumping on board. Charlotte Tilbury's new Magic Serum Crystal Elixir also contains the ingredient, alongside brightening vitamin C and oil-reducing niacinamide. As I tend to splurge on foundation, I decided to opt for the cheaper polyglutamic acid to mix with Charlotte Tilbury's Beautiful Skin Foundation.

On the back of my hand, I pumped a little foundation and followed with an equal amount of polyglutamic acid serum, mixing the two together with the end of my foundation brush. I have to admit, I panicked a little. The two products just didn't want to join forces and ended up a curdled mess! In the name of Beauty In A Tik, I persisted — and actually, I'm quite glad I did. Surprisingly, the concoction applied smoothly over my skin and totally changed the consistency of the foundation, which I find a bit too heavy on its own. I was impressed by both the coverage — lightweight, yet substantial enough to cover my acne scars — and the luminosity. My skin was glowing in all the right places.

Wary of the initial pilling on the back of my hand, I monitored my makeup throughout the day. Usually, after a good eight hours of wear, I'd have to dab my under-eyes and smile lines — areas where my foundation always ends up creasing — countless times, but I can honestly say that there was no need.

I think this comes down to a combination of two things: Polyglutamic acid is so hydrating (supposedly 10 times more so than hyaluronic acid), so it plumped out and ironed away my dehydration lines. Then there's the coverage. I've found that thicker foundation textures often crease throughout the day, but as the polyglutamic acid diluted my base, I didn't face any of those annoying gripes. A little serum goes a long way, too.

This series has taught me that there are so many TikTok makeup hacks which are useless, like using lube as primer and applying foundation with a jade roller (don't bother). But I can't deny that this one works to make foundation look perfectly natural. This spring, when I want to tone down my makeup coverage, I won't invest in a BB cream or a new tinted moisturizer. This is just as good and it has incredible skincare benefits.

Polyglutamic acid wins.

This story was originally published on Refinery29UK.