Beauty Skincare The TikTok-Famous Serum That "Changed" Hailey Bieber's Skin Is on Rare Sale for Prime Day Snag the potent Beautystat vitamin C serum for 20 percent off. By Christina Butan Christina Butan Instagram Christina Butan is an Ecommerce and news writer with five years of experience. She focuses on fashion, beauty, home, lifestyle and celebrity commerce content and strategy for InStyle and PEOPLE. Before covering all things shopping, she was an editorial assistant and freelance writer at PEOPLE for two years, where she fact-checked limited edition print issues, reported on celebrity news, the royals, pop culture, and more. Her writing has also appeared on Real Simple, Health, Travel + Leisure, among other digital publications. She is a graduate of SUNY Purchase, where she was awarded the Peter Keller Journalism Prize. InStyle's editorial guidelines Published on July 13, 2022 Pin Share Tweet Email We independently research, test, review, and recommend the best products—learn more about our process. If you buy something through our links, we may earn a commission. Photo: Instagram @beautystat It's no secret that Hailey Bieber has good skin, and fortunately for us, she's always sharing her favorite beauty products with her fans. Amongst all the goodies in her arsenal is one particular serum that Bieber has claimed transformed her skin — and you can get it on sale during Prime Day. The serum in question is none other than the Beautystat Universal C Refiner Serum, which went viral on TikTok last year (the brand's hashtag has racked up 9.3 million views to date). Bieber spoke about the serum in a YouTube video as part of a series highlighting her favorite Black-owned beauty products. "It's the world's first serum containing 20 percent stable and pure vitamin C, which was groundbreaking in the skincare industry," Bieber said. "It has changed my skin. One of my holy grail products." You can currently snag the serum for as low as $24 during Amazon Prime Day if you opt for the travel-size version. Courtesy Shop now: $24 (Originally $30); amazon.com Courtesy Shop now: $64 (Originally $80); amazon.com The potent formula, which also includes hydrating squalane and exfoliating tartaric acid (naturally found in certain fruit) alongside vitamin C, has several benefits, from fading dark spots to firming the skin to tightening pores. Bieber isn't the only one who noticed a drastic difference after using it — Amazon shoppers said they "immediately saw a difference" and that it's led to much firmer and smoother skin. "I had a very dark sunspot on the side of my nose, [now] it is almost gone," one shopper raved. "My skin is very hydrated and looks dewy without being oily. I have found the missing key to my skin regimen!" Bieber is also a fan of the brand's Universal Pro-Bio Moisture Boost Cream, which she called an "everyday all-around solid moisturizer," and Universal C Eye Perfector. Both products are marked down during Prime Day, along with the rest of the Beautystat lineup. Courtesy Shop now: $40 (Originally $50); amazon.com Courtesy Shop now: $52 (Originally $65); amazon.com The Beautystat Universal C Refiner Serum doesn't normally go on sale, so make sure to add it to your cart for less while you can — Prime Day will be over before you know it. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit