What is vitamin C? Vitamin C is one of the most popular skincare ingredients, but is it worth the hype? With an abundance of research backing its impressive benefits, the answer is unequivocally yes. We’ll delve into how this powerful antioxidant works, how to fit it into your routine and which forms are most effective. What we'll discuss: Is vitamin C good for the skin? Do you need vitamin C in your skincare routine? What are the benefits of vitamin C? How does vitamin C work? Forms of vitamin C in skincare Vitamin C formulas When and how to use vitamin C in your routine What not to use with vitamin C Is vitamin C good for the skin? One of the reasons Vitamin C is so effective and fits so easily into your routine is because it is a natural component of healthy skin. When we're young, the vitamin C levels in skin's primary layers (epidermis, the outer layers, and dermis, the middle layer) are abundant. But as we age, these levels naturally deplete and our skin becomes less able to store vitamin C from foods or supplements. Unprotected sun exposure and pollution accelerate this decline, leading to dull and uneven skin that is less firm than it once was. Luckily, topical vitamin C solutions can help mitigate this damage so our skin can look and feel healthier, not to mention better able to repair visible damage. Do you need vitamin C in your skincare routine? Yes if you're looking to target dull or uneven skin tone, fine lines, wrinkles and lax skin. Vitamin C can help meet these needs. Also, it is such a powerful antioxidant that vitamin C can provide a strong defence against environmental stressors (including sun damage), which all of us eventually see visible signs of at some point in our lives. What are the benefits of vitamin C? There are many benefits, including the ability to even out skin tone and diminish the appearance of fine lines and wrinkles. While this powerhouse ingredient is well known for skin brightening results, research also shows that it can shield the skin from visible impacts of environmental stressors, including free radical damage. This synergy of mitigating problems both before and after they occur makes vitamin C a real superpower ingredient. How does vitamin C work? It is a natural component of skin, supporting important functions. For example, it firms the architecture of the skin by stimulating beneficial substances like collagen, which defends against oxidative damage (caused by sun exposure) and regulates melanin production to disrupt factors triggering the development of dark spots and uneven tone. In fact, it’s the most abundant antioxidant found in skin! The research shows that as we age and as we’re exposed to environmental stressors (such as UV rays and pollution), these high vitamin C levels get depleted. Applying a vitamin C product topically – when formulated and packaged correctly – can help counter some of the visible effects (think dark spots, wrinkles and loss of firmness) that occur from this depletion. Forms of vitamin C in skincare There are many forms of vitamin C for skin and while they all have antioxidant benefits, they each work slightly differently. Some are even more effective than others. Ascorbic acid – also known as L-ascorbic acid – has the most skin-related research of any form of vitamin C. When properly formulated at a pH of less than 4 (2.6-3.2 is the ideal range) and used in concentrations of 5% or greater, this form helps create younger-looking, firmer-feeling skin while fading signs of uneven skin tone and darker spots. Ascorbic acid also helps the skin’s surface defend itself from free radicals and external stressors, lessening the effects of exposure to the elements. 3-O ethyl ascorbic acid is considered a next-gen form of vitamin C that’s highly stabilised and is both water- and oil-soluble. Its research-backed benefits include brightening and evening out skin tone, soothing and boosting elasticity by neutralising stressors that would otherwise damage skin’s supportive elements. Other beneficial forms that have notable research demonstrating their efficacy: Ascorbyl glucoside is a stable, water-soluble form of vitamin C proven to brighten dullness, inhibit triggers of discolouration and stimulate firmer-feeling skin. It’s considered gentler than certain other vitamin C derivatives due to the unique way it converts to pure vitamin C within the skin. Ascorbyl palmitate is an oil-soluble, non-irritating (pH-neutral) vitamin C derivative that’s often combined with more potent forms of vitamin C to promote firmer skin and reduce the appearance of discolourations. However, high amounts of this ingredient can lend unpleasant aesthetics to skincare products. Magnesium ascorbyl phosphate promotes deeper hydration but it isn't as potent an antioxidant as pure vitamin C. Still, it is considered one of the more stable forms. Sodium ascorbyl phosphate is a form of vitamin C with research showing it can influence factors linked to breakouts, likely due to its soothing effect. Tetrahexyldecyl ascorbate is a lipid (fat) soluble form of vitamin C, backed by research for its ability to mitigate damaging effects of UV exposure. Some researchers theorise that it has a greater affinity for skin due to its fatty acid component that helps aid penetration. Keep in mind that even the more stable forms of vitamin C will break down over time if routinely exposed to heat, air and light. To see the best results from your vitamin C eye cream or moisturiser– packaging matters. Look for opaque, air-restrictive bottles or pump containers to help ensure the ingredients remain stable. A vitamin C cream that comes in a jar, unfortunately, won’t remain effective for very long. Vitamin C formulas Research shows that moderate to high strengths of vitamin C are particularly effective and provide a host of benefits for the skin: from 5% and higher, with amounts of 10% and above typically found in targeted treatments. If your skin looks dull or has an uneven tone, regardless of your skin type, a lightweight liquid 15% vitamin C booster is ideal for layering. If stubborn dark spots are more your concern, a 25% vitamin C skin treatment works great for discolourations. Lower concentrations of vitamin C (5% or less) are good for your skin as well, providing cumulative benefits in leave-on products like moisturisers, eye creams, serums and SPF moisturisers too. In fact, research has shown that concentrations below 1% provide antioxidant and anti-ageing benefits to the skin. Lower strengths of vitamin C also help enhance the benefits of other youth-preserving ingredients, for instance retinol and ceramides. When and how to use vitamin C in your routine All forms of vitamin C mix well and layer with other skincare ingredients, including retinol, niacinamide and exfoliating acids like salicylic acid. Vitamin C skincare products can be used twice daily, both morning and night. After cleansing, toning and exfoliating, apply the rest of your products in order from thinner to thicker textures (usually, serum, moisturiser, treatments). During the day, always finish with an SPF moisturiser with a broad spectrum factor of 30 or higher. What not to use with vitamin C A myth we love to clear up – there are no skin-beneficial ingredients you cannot use with vitamin C. Despite the idea that other powerhouse ingredients such as niacinamide, hyaluronic acid and retinol can counteract or nullify the effects of vitamin C, that is simply not the case. In fact, using these ingredients together only enhances their efficacy. We will say that there are some ingredients not to use with vitamin C, like fragrance and denatured alcohol, but those are the drying and irritating ingredients that you shouldn't include in your routine anyway! References for this information: 1. The Journal of Clinical and Aesthetic Dermatology, July 2017, pages 14-17 2. Nutrients, August 2017, ePublication 3. Dermatologic Surgery, July 2005, pages 814-817 4. Journal of Cosmetic Dermatology, September 2021, pages 2,349-2,359 5. Cosmetics, September 2019, pages 1-8 6. Free Radical Biology and Medicine, September 2021, pages 151-169 7. International Journal of Cosmetic Science, February 2009, pages 41-46 8. International Journal of Cosmetic Science, June 2005, pages 171-176 9. The Journal of Clinical and Aesthetic Dermatology, April 2019, pages 46-53 10. Clinical, Cosmetic and Investigational Dermatology, May 2018, pages 253-263 11. Journal of Cosmetic Dermatology, February 2019, pages 236-241 12. The Journal of Clinical and Aesthetic Dermatology, July 2019, pages 14-17 13. Journal of Drugs in Dermatology, Volume 7 Supplement, July 2008, pages S2-S6 14. Clinical, Cosmetic and Investigational Dermatology, November 2013, pages 281-288 Related articles Glutathione for the skin Mandelic acid: what is it and how can I use it? Can you use retinol with vitamin C, BHA, AHA & niacinamide?