Lactic acid possibly already features in your skincare line-up, but if you’ve never given much thought to just how hardworking it is, it’s time to brush up on the topic. Adept at softening and smoothing skin by gently but effectively exfoliating the top layer of skin, or the epidermis, lactic acid can significantly improve the appearance of all skin types with regular use. Here’s what you need to know.
What is lactic acid?
Lactic acid is an exfoliant derived from the fermentation of lactose found in milk. You might recognise it as Cleopatra’s skincare ingredient of choice, although today’s sophisticated formulations mean there’s thankfully no need to bathe in sour milk in order to benefit. An alpha hydroxy acid, or AHA for short, lactic acid is from the same family of acids as glycolic acid and mandelic acid, and like them is renowned for its ability to encourage cellular turnover and keep skin healthy and bright.
How does it work on the skin?
A water-soluble compound, lactic acid works by breaking down dead skin cells. “Lactic acid disrupts the bonds between dead skin cells in the outer layer of the skin, allowing them to be shed more easily,” explains Dr Derrick Phillips, CeraVe’s consultant dermatologist. “This process not only reveals fresher and more youthful-looking skin but also helps to unclog pores.” Because it’s a larger molecule than other AHAs, lactic acid can’t penetrate the skin as deeply, and so it’s ideal for more superficial exfoliation on the surface of the skin. As well as giving brightening benefits, that means it’s a great option for anyone with sensitive skin, as it doesn’t have as much potential to irritate.
What are the benefits of using lactic acid?
Skin brightening is one of the main benefits of using lactic acid, which means softer, smoother skin comes as standard, but it also plays a part in diminishing the appearance of fine lines and wrinkles. That’s because they’re often formed in the very top layers of skin and once you eliminate those, you reveal the fresh, younger skin underneath. “Lactic acid can stimulate production of collagen and structural molecules called glycosaminoglycans (GAGS),” adds Dr Phillips, “which results in firmer and plumper skin with fewer fine lines and wrinkles.” The same is also true of shallow hyperpigmentation and even some spots and imperfections. “It has been shown to be effective at killing bacteria in the skin and some studies show it to be helpful in reducing acne lesions,” says Dr Emma Craythorne, consultant dermatologist and Klira Founder, so look out for it in your spot treatments too.
Another major benefit of lactic acid is its ability to hydrate skin. Unlike other AHAs, lactic acid has a unique structure that allows it to bind with water in the skin. This helps keep it hydrated by promoting moisture and encouraging skin to hold on to more of its own natural reserves. Skin barrier health may be a buzz phrase in beauty right now, but it’s essential if you want a healthy, hydrated complexion. A key component in this, lactic acid encourages the skin to make more ceramides, the lipids that form the glue between skin cells, helping to maintaining the skin barrier’s integrity and reduce inflammation.
Can lactic acid be used on the body?
Its exfoliating prowess means lactic acid is an excellent ingredient to incorporate into your top-to-toe exfoliating regime. If you have dry, scaly or bumpy skin on areas like your elbows, knees or the backs of your arms, it does a great job of sloughing off skin and helping to keep it smooth and soft, while also protecting the skin barrier’s integrity. “It’s very, very good for keratosis pilaris,” adds Dr Craythorne.
What’s the best way to use lactic acid?
Its versatility means lactic acid is found in many different formulations. Depending on what you’re looking to achieve, you can use it in any type of product you like, although it’s commonly combined with other hardworking AHAs in toner or serum form, which offers even better exfoliating results. “The optimal percentage is the concentration that you can tolerate and comfortably incorporate into your skincare routine,” advises Dr Phillips. “Higher concentrations are not necessarily better and jumping to a high concentration may cause unwanted skin irritation. It is best to establish a percentage that your skin can tolerate and gradually increase over time. If you are new to lactic acid, I would recommend products containing five to 10%.”
If you want more of an intensive treatment, then it’s worth looking at lactic acid peels done in a professional setting, where concentration strengths can be greater. “At home strength is around 10 to 20%, and you are less likely to have problems, plus this can be just as effective when used daily or several times a week,” says Dr Craythorne. “An in-clinic peel would be for a more dramatic result, and if it’s being used as a professional peel it will be more than 30%. That would be a strong exfoliating peel which some people might use for fine lines, ageing and removing blackheads.”
Can you use lactic acid every day?
Unlike some BHAs like salicylic acid, which treat deeper layers of the skin, and even some other AHAs, lactic acid is usually a safe – and effective – bet for almost everyone. That said, you should always exercise caution when using actives in your routine, which means not overdoing it, even if it seems to be working well. “Most people are unable to tolerate using lactic acid every day, unless at very low concentrations,” warns Dr Phillips. “Daily use may cause excessive exfoliation, disruption of the skin barrier, dryness and irritation. It will also increase the sensitivity of the skin to sunlight, increasing the risk of sunburn.” For best results (and a happy, healthy skin barrier long-term) try to incorporate your chosen lactic acid product two to three times a week – provided your skin can tolerate it.
This article was originally published on British Vogue.