What is Lactic Acid? Benefits, Treatments, Etc.
So what does lactic acid do?
It brightens and resurfaces the skin, helps with rosacea, protects the skin barrier and locks in moisture (Agent Nateur.) Here's the official definition:
Lactic acid is a gentler form of alpha-hydroxy acid (AHA). AHAs are organic, naturally-occuring acids found in foods and milk sugars. AHAs include glycolic acid (GA), citric acid (CA), malic acid (MA), tartaric acid (TA), and lactic acid (LA). (National Library of Medicine). AHAs can be used in a wide spectrum of skin treatments such as acne, scars, melasma, hyperpigmentation, etc.
The nice thing about lactic acid is that it's mild, and not abrasive like the majority of other acids. One of my favorite products infused with lactic acid is the Agent Nateur holi(mask). It is not only gentle, but effective. It's called "Botox in a jar" because truly after just one use, your skin is tighter, brighter and visibly less dull.
How do you incorporate into your skincare routine?
Lactic acid works really well paired with Vitamin A (aka retinol) but it can also be a great option if you can't (or prefer not to) use retinol.
Lactic acid, similarly to retinol, increases cell turnover and removes dead skin cells. This, in turn, will help improve the overall skin texture. Not to mention, it helps the skin retain moisture. As you can imagine this is a less abrasive way of getting that cell turnover because retinol can definitely irritate the skin (especially the less diluted it is.) Read this breakdown of vitamin A to understand the ins and out.
With lactic acid, just as we know with retinol, you want to 10000% use an SPF. Anything that exfoliates and removes dead skin cells increases skin's sensitivity to UV rays. It's important to really lather that SPF when using lactic acid.
How often should you use it?
Lactic acid skin care products come in varying concentrations and it's always best to follow the label's instructions. In my experience, a serum with a 5% concentration of lactic acid is mild enough to use every other day. However, the concentrations can go up from there.
If you tend to have more sensitive skin, you can limit lactic acid to 1-2 times a week. However if your skin is used to consistent exfoliation, you can use lactic acid products on the daily. You may already be using products that have lactic acid in them, but you may not be aware.
Is it okay for sensitive skin?
Actually the founder of Agent Nateur references lactic acid over glycolic and salicylic because of its gentle nature in comparison to these other two acids. She specifies that lactic acid has been found to increase the levels of ceramides in the the skin and studies have also shown that this increase in ceramides leads to improvements in the barrier function of the skin (think thicker stronger skin) which in turn reduced transepidermal water loss. This means that using lactic acid can lead to firmer, plumper, better hydrated skin which will help to reduce and soften the appearance of fine lines and wrinkles (National Library of Medicine.)
What's the final conclusion?
The results demonstrate that cosmetic benefits from the use of alpha-hydroxy acids are caused by modification of the skin surface, the epidermis and the dermis. Although 5% lactic acid modulates surface and epidermal changes, 12% lactic acid influences both the epidermis and the dermis" (National Library of Medicine).
Overall it's clear that lactic acid has a nature to bind water, and along with its antioxidant properties, it truly hydrates the skin.