Skin Texture: We took detailed notes about what our skin texture was like before we used each serum, and recorded how the products interacted with our skin. Did the serum cause any irritation? Did it have a plumping effect or smooth lines and wrinkles? We also recorded how our skin texture changed after the eight-week testing period.

Hyaluronic acid creams may be particularly helpful as skin ages, especially as the levels of hyaluronic acid in the skin drop with age. Made with only seven ingredients, this serum is designed to calm, soothe, and replenish the skin. During testing, we found it to be incredibly effective— we actually noticed a difference in the appearance and feel of our skin on days when we used it vs. the days we didn’t use it. Our skin appeared healthier and younger; wrinkles and fine lines were less obvious, and the overall feel of our skin was supple, smooth, and super-soft. Vitamin C is an antioxidant that’s naturally present in high levels in the skin. It helps protect the skin from ultraviolet (UV) sun and other environmental damage. We spent over 432 hours testing hyaluronic acid serums, and in the end Isdinceutics Hyaluronic Concentrate was the clear winner. The serum left our skin feeling and looking glowy and even reduced the appearance and frequency of acne breakouts. We’ll keep our list updated as we test new products, so watch this space. However, I must admit that I didn't get that energised and rejuvenated look that everyone was raving about and, quite frankly, other products work just as well.An excellent serum for calming irritated or sensitive skin, cult brand Glossier’s Super Bounce serum combines the hydrating power of hyaluronic acid with healing and moisturising vitamin B5. The result is deeply hydrated, plumper and bouncier skin that glows from within. The fragrance- and paraben-free serum is suitable for all skin types, including sensitive and inflamed skin, and the formula is particularly beneficial for acne-prone and scarred skin. The serum contains fragrance, and although we found the scent calming and not at all overpowering, it could be irritating to very sensitive skin. Frenkel JS. The role of hyaluronan in wound healing. International Wound Journal. 2012;11(2):159-163. doi:10.1111/j.1742-481x.2012.01057.x According to dermatologists, hyaluronic acid is a gentle active ingredient that can be paired with many other active ingredients. You can use hyaluronic acid in the same routine as ingredients like retinol, vitamin C, and others. However, you should try to avoid layering multiple products that each contain hyaluronic acid. In doing so, you could cause some irritation from using too much of the same ingredient.

A 2015 study involving 60 women with light to medium skin tones had participants in the study group apply a solution containing 5% vitamin C followed by a moisturizer. The control groups applied a moisturizer without the vitamin C solution. If you need extra soothing or hydration, this is the formula to lean on. We found that with repeated use of the product, the inflammation had dissipated, and our skin appeared calmer and less red. Dr Lynch explains why. “The best hyaluronic acid serum can provide a potent hydration boost compared to regular moisturisers," he says. "Regular use can help maintain a healthy skin barrier, preventing dryness, dullness, and flaking, and keeping skin looking youthful.”

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Favuzza E, Cennamo M, Vicchio L, et al. Protecting the ocular surface in cataract surgery: The efficacy of the perioperative use of a hydroxypropyl guar and hyaluronic acid ophthalmic solution. Clinical Ophthalmology. 2020;14,1769–1775. doi:10.2147/OPTH.S259704 Because hyaluronic acid can be a large molecule, it's difficult for the ingredient to penetrate the top layers of the skin, so you want to look for a formula that features varying weights and sizes of hyaluronic acid molecules, instructs Dr. Gohara. If you use one with just one size that’s too big, the product will just sit on top of your skin and you won’t get any long-term hydrating benefits. Think about other ingredients in the formula. So, as a HA serum superfan, most of my favourite, tried-and-tested, repeat buys are on this list. I know these products inside out – often using them for months if not years at a time. Jegasothy SM, Zabolotniaia V, Bielfeldt S. Efficacy of a New Topical Nano-hyaluronic Acid in Humans. J Clin Aesthet Dermatol. 2014;7(3):27-29. Farmacy Filling Good Hyaluronic Acid Serum: A clean option, we like the gentle ingredients in this formula for those with sensitive skin or anyone who actively avoids fragrance, parabens, and the like. We wanted to love it as much as the ingredients list, but at the end of the eight-week testing period, we couldn’t tell much of a difference. Compared to others we tested, this one fell short, though it feels and smells nice.

Our editor with dry skin gave this serum a try and had nothing but positive results. It smoothed out fine lines and wrinkles, got rid of some stubborn dry patches, and significantly reduced redness, giving our editor enough confidence to go without makeup. Clinique Moisture Surge 72-Hour Lipid-Replenishing Hydrator Moisturizer ( Ulta.com) contains sodium hyaluronate and no fragrance, meaning it’s gentle on sensitive skin. One thing I will also say, is that it works well as a base for your make-up - particularly foundation - as it almost felt like a primer that prepped the skin. Gross C, Dhawan A, Harwood D, Gochanour E, Romeo A. Glenohumeral joint injections. Sports Health: A Multidisciplinary Approach. 2012;5(2):153-159. doi:10.1177/1941738112459706It’s up to you if you use your HA serum as part of your morning or your night-time routine; if applying in the morning, give the product time to sink in before applying moisturiser and makeup, as serum formulations can be quite runny and may cause your makeup to slide off if not properly absorbed. To compile this list, our team of editors spent hours researching the best hyaluronic acid formulas on the market, evaluating features like ingredients, size, and design, before landing on about 30 formulas to try out for ourselves. We tested each formula over the course of eight weeks, taking into account how well each serum absorbed into our skin, whether or not the serum left a residue behind, and how our skin looked and felt after the testing period. Throughout the testing period, our skin felt more hydrated overall (a huge win), with a huge difference in the softness of previously dull and dry areas on our faces. Our T-zones never felt too oily; rather, the serum provided a supple, glossy feel that proved to be a great base for both skincare and makeup. The only thing we wish we could change is that the bottle is a bit small; a larger bottle would last longer. But when you consider the price and accessibility (you can find it in any drugstore, no matter where you are), it can’t be beaten.