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Lactic Acid in Skin Care

Lactic Acid in Skin Care


Lactic acid is a skincare ingredient that has been used for centuries to smooth, brighten and hydrate the skin. Cleopatra herself used to bathe in soured milk and honey…reportedly for the skin smoothing and rejuvenating properties it was able to provide…and if it’s good enough for an iconic Egyptian queen, it’s good enough for me!

Produced from the fermentation of lactose (found in milk), this water-soluble alpha-hydroxy-acid (AHA) has been incorporated into a variety of at-home and in-office treatments.

When applied to the skin, lactic acid exerts effects at the epidermal layer by breaking down the bonds between cells, thereby providing a gentle exfoliating effect. At the deeper level of the dermis, they are able to increase collagen and mucopolysaccharide formation – thus improving skins firmness and smoothness.

The unique properties of lactic acid being a larger molecule than its AHA cousins; for example, glycolic and mandelic acids, mean that it has additional benefits of skin hydration, which these other acids do not. Think brightening, hydrating, polishing, and firming…these are the benefits you can expect if you choose to introduce lactic acid to your routine!

Let’s delve a little deeper…

Lactic acid has the following benefits and properties:

  • Increases cell turnover and provides gentle exfoliation
  • Gives a brighter and smoother complexion
  • Improves pigmentation
  • Improves fine lines and wrinkles
  • Has antimicrobial properties which can help inflammatory skin conditions such as eczema, psoriasis and acne
  • Improves acne lesions

Lactic acid has the ability to penetrate as deeply as the dermis when used in concentrations of 12% (think level 1 or 2 in the adjacent diagram).

At lower concentrations, you’ll get the epidermal, or more superficial, effects of smoothing and hydrating the complexion.

Dr. Walter Smith Ph.D. compared the effects of 5% and 12% lactic acid on the skin, looking at how deeply it penetrated and what the effects in the skin were. At 12% concentration, lactic acid penetrated through the epidermis to the dermis underneath, with benefits in increasing the skin’s thickness and firmness and improving collagen production. At 5% concentration, the effects were seen at the epidermis, however, he still was able to demonstrate improvements in skin firmness using this concentration over a period of 4 weeks.

Lactic acid has also been studied with regards to its application in photo-aging in this paper by Stiller, Bartolone, and Stern (1996), they demonstrated that 8% lactic acid was able to significantly improve the appearance of moderate-severe signs of photo-damage (pigmentation, roughness, sallowness, and fine lines and wrinkles) when compared to a placebo. These benefits were seen after use for 22 weeks.

How can I add lactic acid to my routine at home?

If you’re considering adding lactic acid to your routine, it’s perfect for you if you have sensitive or acne-prone skin, as well as want to improve hydration and manage the signs of photo-aging. It’s gentle, anti-inflammatory and on the most part, well-tolerated.

General tips

Tip #1

Even though it’s a mild exfoliant I’d still recommend not to use too frequently – low concentrations can be used daily but ideally every few days. The “3-on 3-off method” advocated by celebrity skin specialist Renée Rouleau advises using lactic acid for 3 consecutive nights and then having 3 nights off. Use your nights off to hydrate and nourish your newly exfoliated skin that’s just been uncovered.

Tip #2

Use it at night as a leave-on treatment to get the most benefit and to give the product time to penetrate. You can also incorporate it as a daily wash at low concentrations.

Tip #3

Avoid using alongside retinoids and other exfoliants. The reason here is that you’ll likely cause over-exfoliation and you risk increased adverse effects of redness, swelling, and damage to your skin barrier.

Tip #4

Always use SPF. As you’ll be uncovering fresh new skin, it’s essential to use SPF of at least 30 on sun-exposed, AHA-treated areas.

Tip #5

You can reduce the chance of side effects with your at-home products by selecting products that are formulated for your skin type, have a concentration of less than 10%, and have a pH of greater than 3.5

Tip #6

Lactic acid also works well with other AHAs and hyaluronic acid. When used together, hyaluronic acid further enhances skins hydration and plumpness.

So what are the potential drawbacks of lactic acid?

Adverse effects with this gentle acid are uncommon, but they can include redness, swelling, burning and itching sensation, and visible peeling of the skin.

Over-use or higher concentrations can also increase your risk of post-inflammatory hyperpigmentation, so be sure to select the right formulation and concentration for you. If you’re not sure, you can always conduct a patch test to check before using it on your whole face. Here’s how to patch test, according to Jennifer M. Segal, MD, a board-certified dermatologist and founder of Metropolitan Dermatology Institute in Houston, who spoke with wellness blog, The Healthy.

Some of my favourite products for at-home use:

At-home lactic acid skin care
At-home lactic acid treatments. I have no financial interest in any of these brands, they are simply products I have tried and like to use!

1) Sunday Riley Good Genes All-In-One Lactic Acid Treatment – formulated with purified, high-potency lactic acid, this product is great at exfoliating, hydrating, and smoothing the skin. It can also help improve pigmentation with continued use.

2) The Ordinary Lactic Acid 10% + HA – the addition of hyaluronic acid makes this a great smoothing and hydrating treatment to use at home.

3) REN Clean Skincare Ready Steady Glow Daily AHA Tonic – lactic acid combined with azelaic acid and willow bark all work to brighten the complexion and give your skin a glow.

4) Ameliorate Transforming Body Lotion – a great product to use for your body to smooth and hydrate your skin. This can be used to treat keratosis pilaris (goose-bump skin) and exfoliate and renew skin cells while adding hydration.

If you’re looking for a more intensive lactic acid treatment, take a look at what an in-office lactic acid peel can do for your skin here.

Masters in Clinical Dermatology Dissertation. This PDF download is provided for personal use and is the intellectual property of Dr. Sarah Tranter  and Dr. Tranter Aesthetics. It cannot be copied or reproduced without permission.

The Efficacy and Safety of Topical Retinoids for preventing and reversing the effects of photoageing (pdf)

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