While many skincare ingredients come and go, acids have stood the test of time when it comes to exfoliation, cleansing, and hydration. If you feel like you’re constantly playing a guessing game when it comes to choosing acid-based products for your dark spots, acne, fine lines, or dry skin, you’re not alone. So if you don’t know your lactic from your glycolic and can barely even pronounce hyaluronic let alone understand what it does, we’re here to change that.
Here are eight of the best tried and tested skincare acids we think you should get to know. In no particular order, say hello to…
Otherwise known as sodium hyaluronate or hyaluronan, hyaluronic acid is quite different from most facial acids, which typically exfoliate the skin. Nevertheless, it’s one of the most popular ones in skincare and for good reason.
Hyaluronic acid (or HA for short) is a molecule that is produced naturally by the human body. It works as a lubricant in your eyes and joints and is a major component of your skin’s structure where it acts as a powerful humectant, which attracts water molecules to hydrate the skin.
Studies have shown that hyaluronic acid can hold almost 1,000 times its weight in water, which makes it one of the best humectants in the world (either natural or synthetic) for retaining moisture. And that’s not all. Hyaluronic acid also helps reduces inflammation, promotes collagen production, strengthens your skin’s unique microbiome, and fights free radicals.
However, like most good things in the human body, your levels of naturally-occurring hyaluronic acid drop as you age. Inflammation and sun damage also cause further depletion, so it’s important to look to an outside source of hyaluronic acid after the age of 30 to maintain soft, plump, and youthful-looking skin.
The answer is to include hyaluronic acid in your daily skincare routine.
Lactic acid is a is part of a group of acids known as alpha-hydroxy acids, or AHAs.
AHAs are water-soluble chemical compounds that stimulate exfoliation. Unlike physical exfoliants that use tiny beads, seeds or (often harsh) pieces of shell to slough away dead skin cells, AHAs work by breaking down and dissolving the bonds between skin cells to gently remove the dead skin cells. This increase in cell turnover also stimulates collagen and elastin production, which leads to smoother, softer skin and a reduction in fine lines, discoloration, and even acne scars.
Lactic acid is extracted from sour milk and is also known to increase water retention and boost ceramides in the skin’s protective barrier, which is perfect for dry, dehydrated or sensitive skin types. Studies also show that it may help kill bacteria, which is awesome news for acne sufferers.
Due to its larger molecular size, lactic acid doesn’t penetrate as deeply as other AHAs, making it ideal for treating surface issues like dullness, sun damage, and light scarring from acne spots. It’s also why it’s known as the ‘sensitive skin acid.’
Fancy trying a little lactic acid in your skincare routine? Then try our Overnight Star Lactic Acid Treatment, a gentle but powerful exfoliating treatment that also contains hyaluronic acid (as a bonus) to hydrate and moisturize as you sleep.
L-ascorbic acid is one of the most studied and effective ingredients in skincare. Those may sound like bold words, but there’s a lot of science to back up the benefits of l-ascorbic acid, or vitamin C as you more commonly know it.
Firstly, vitamin C is a powerful antioxidant, which means it has the power to hold off damage to the skin caused by lifestyle or environmental-induced free radicals (like UV radiation, stress, or a poor diet). Vitamin C also helps soothe the skin, brighten dullness, fade discolorations, reduce lines, and protect the skin against sun damage.
Although somewhat sensitive to light and air, vitamin C, when used in the correct form and concentration, improves the quality of your skin.
Most studies agree that l-ascorbic acid is the most effective form of vitamin C (others include sodium ascorbate, ascorbyl palmitate, and sodium ascorbyl phosphate), but it must be formulated in a high concentration and at a low pH for it to penetrate the skin efficiently. This means you should look out for products that contain at least 10 percent l-ascorbic acid and a maximum pH of 3.5 for it be beneficial to your skin. However, always do a patch test before adding it to your daily routine.
Like lactic acid, glycolic acid is a water-soluble AHA that renews your skin.
Derived from sugar cane, glycolic acid contains very small molecules – the smallest of all AHAs – which means it penetrates the skin very effectively to work its magic and speed up cell turnover. It is excellent for repairing photodamage, reducing acne, smoothing fine lines, and fading dark spots and is often used in professional chemical peels.
However, glycolic acid is not tolerated well by all skin types, especially those with sensitive skin or rosacea. It also makes your skin more sensitive to the sun, so wearing a broad-spectrum protective moisturizer with an SPF of 30 or above is a must while using it. If you ask us, we prefer lactic acid to glycolic acid.
Topical retinoic acid, which is also known as tretinoin, is a prescription-only retinoid (retinol is its over-the-counter, gentler cousin) and often seen as the top dog of anti-aging ingredients.
Retinoids are vitamin A derivatives that work by stimulating skin turnover more efficiently. They also help the outermost layer of the epidermis, the stratum corneum, by increasing the presence of skin-nourishing glycosaminoglycans to help soften and visibly improve the plumpness of your skin. If that sounds like a lot of science, all you need to know is that retinoids target concerns like wrinkles, sagging skin, dark spots, acne, and milia (small white bumps created by dead skin trapped below the skin's surface).
Retinoic acid is the most potent, active form of vitamin A, which makes it fast and effective. It is only available by prescription, however, and should only be used under strict instructions. On the other hand, non-prescription retinol is more forgiving and has fewer side effects, if any, but offers very similar benefits as long as you are patient. While topical retinoic acid can give you visible results in just a couple of months, retinol can take up to six months.
Salicylic acid is derived from willow tree bark and, like lactic and glycolic acids, is another effective skin exfoliating acid. Unlike its water-soluble AHA buddies, however, salicylic acid is a beta hydroxy acid, or a BHA.
BHAs are oil-soluble substances, which means they not only exfoliate the top layers of your skin, but also penetrate through the lipid layers of your skin and into the sebaceous glands where they cut through excess sebum. Sebum is essential to the health and suppleness of your skin, but too much of it can clog your pores, which in turn leads to blackheads, whiteheads, and pimples. This makes BHAs outstanding compounds for fighting acne.
Without a doubt, salicylic acid is a powerful exfoliating ingredient, and it has awesome antibacterial and anti-inflammatory properties as well. This helps calm redness and reduce the recovery time of breakouts.
OK, so it may not have ‘acid’ in its name, but don’t let that fool you because gluconolactone is another acid exfoliant that totally deserves a mention.
Gluconolactone is a poly hydroxy acid, which makes it a PHA.
Much lesser known than the As and Bs of this world, PHAs have similar benefits, but due to their larger molecular size, they work on a very superficial level to provide much gentler exfoliation. This makes them a great choice for extremely sensitive skin types that have problems dealing with other more potent acids like glycolic and salicylic acids. Gluconolactone can even be gentle enough for those with rosacea or eczema.
Ferulic acid is a plant-based substance that is derived from the seeds of certain fruits, vegetables, nuts, or grains. A powerful antioxidant, ferulic acid fights pesky free radical damage and, like vitamin C, is also thought to help protect the skin from the sun.
So what makes it so special? Well, its biggest impact comes from the clever way in which it works with other antioxidants, like our good friends vitamins C and E. For example, ferulic acid helps lower the pH level of l-ascorbic acid to make it more stable and, therefore, more effective. Research also suggests that the combination of ferulic acid with vitamins C and E may offer eight times more environmental protection than the same ingredients can offer alone.
The only drawback is that ferulic acid has a rather unusual metallic scent and is often referred to as smelling a bit ‘hot doggy.’ Does the smell outweigh its skincare benefits though? No way.