The Ordinary lactic acid serums are two The Ordinary products that provide rather quick visible results and can be purchased at very low prices (see my complete review here). The Ordinary offers two different strength lactic acid serums: one at a 5% concentration and the other at a 10% concentration. But how should these lactic acid serums be used?
Today we’ll be discussing how to use The Ordinary lactic acid serums and how to easily incorporate them into your skincare routine.
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What is Lactic Acid?
Found naturally in sour milk and synthetically produced for skincare products, lactic acid is an alpha hydroxy acid (AHA) that acts as a chemical exfoliant to sweep away dead skin cells on the surface of the skin to improve dark spots, uneven skin tone, and skin texture while brightening dull skin. It also helps to smooth the appearance of skin and reduce the look of wrinkles and fine lines.
Lactic acid is a good choice if you want an effective chemical exfoliant that isn’t too strong or irritating. Lactic acid has a larger molecule size than glycolic acid, a more potent alpha hydroxy acid, so lactic acid tends to create less irritation, tingling, and redness than a stronger AHA like glycolic acid.
Lactic Acid: Great for Most Skin Types
Lactic acid is a popular skincare exfoliant because it works well for most skin types. It helps to smooth fine lines and wrinkles on aging/mature skin. Lactic acid can help open clogged pores and help reduce acne lesions, making it a good choice for oily and acne-prone skin types.
Lactic acid also has moisturizing properties, which makes it a good option as a mild exfoliant for those with dry skin. Depending on the concentration, it can also be gentle enough for those with sensitive skin.
Lactic Acid Concentrations
Lactic acid can be effective at different concentrations. This study had participants apply either 5% or 12% lactic acid concentrations twice a day for three months. While both concentrations improved epidermal firmness and thickness and skin smoothness, lines, and wrinkles, the 12% concentration of lactic acid also improved dermal firmness and thickness.
The dermis is located beneath the epidermis, so the study indicated that the higher 12% lactic acid was able to penetrate the skin better than the 5% lactic acid concentration.
How To Use The Ordinary Lactic Acid in Your Skincare Routine
The first thing to note about these lactic acid serums is that you should not use them on sensitive, peeling or compromised skin. So if your skin is sensitive, easily irritated, or damaged in any way, you should not use these serums.
Alpha hydroxy acids can make your skin sensitive to the sun, so it is important to apply a broad-spectrum sunscreen with an SPF of 30 or higher while using lactic acid (and all alpha-hydroxy acids) and for a week after.
These lactic acid serums may be diluted with other skincare treatments to reduce their concentration until your skin can tolerate them undiluted. An easy way to dilute them is to mix a drop or two into a few drops of The Ordinary Hyaluronic Acid 2% + B5 Serum.
How Often To Use Lactic Acid in Your Skincare Routine
First choose a lactic acid concentration: The Ordinary Lactic Acid 5% + HA or The Ordinary Lactic Acid 10% + HA. If you are new to acids, start out using The Ordinary lactic acid serum once a week. See how your skin responds and slowly increase usage as your skin builds a tolerance. While you can use the lactic acid serum daily, most can get good results using lactic acid 2 or 3 times a week. Try to use it in the evening if possible.
The Ordinary recommends patch testing before using their lactic acid serums and any new product. For additional details on patch testing, please see their patch testing guide.
When To Use The Ordinary Lactic Acid Serums in Your Skincare Routine
These water-based lactic acid serums should be applied during the treatment step of your skin routine, which is after cleansing and toning, but before other serums and moisturizers.
What Not to Mix with The Ordinary Lactic Acid Serums
Since lactic acid is potentially sensitizing, you should not use it at the same time as other direct acids like salicylic acid or azelaic acid, other AHAs like glycolic acid or mandelic acid, or other actives like benzoyl peroxide acne treatments.
You should also avoid using lactic acid with strong actives like pure vitamin C (ascorbic acid). Ascorbic acid works best at a pH of 3.5 or under. The Ordinary lactic acid serums are formulated at a pH of 3.6 – 3.8. While the lactic acid pH should be close enough not to compromise the effectiveness of ascorbic acid, you may experience redness, stinging, peeling, or irritation if you use both ascorbic acid and lactic acid at the same time. Your best bet is to use ascorbic acid in the morning and lactic acid in the evening or use them on different days.
Retinol and retinoids increase cellular turnover and remove dead skin cells. Since lactic acid also works to sweep away dead skin cells, you may overdo it, causing irritation and redness if you use both simultaneously. Additionally, the pH of retinol is higher than acidic lactic acid, so using them together may render both much less effective.
These lactic acid serums conflict with peptides like The Ordinary “Buffet” serum or The Ordinary “Buffet” with Copper Peptides since the low pH of lactic acid may compromise the effectiveness of the peptide products. The Ordinary also notes that their lactic acid serums are not compatible with their EUK 134 0.1% antioxidant serum.
The Ordinary Lactic Acid 5% + HA
The Ordinary Lactic Acid 5% + HA is an alpha hydroxy acid serum and mild superficial peeling formula that exfoliates the skin. This is the milder of the two The Ordinary lactic acid serums, as it contains 5% lactic acid. The serum contains a purified Tasmanian pepperberry derivative to help offset the irritation that often comes along with chemical exfoliation.
This lactic acid serum also contains sodium hyaluronate crosspolymer, a cross-linked type of hyaluronic acid with even better moisture-retention abilities than traditional hyaluronic acid. It forms a film on the skin’s surface that delivers moisture over an extended period of time compared to regular hyaluronic acid. Glycerin, a humectant, is included for additional moisture.
Both The Ordinary lactic acid serums are formulated at a pH between 3.60 – 3.80. This is important because lactic acid has a pKa of 3.8. PKa denotes acid availability. So when pH and pKa are close, salt and acidity are in balance, and the formula will reach prime effectiveness with minimum irritation.
This low 5% concentration lactic acid product is a great option for those new to acids and for those with sensitive skin. It gently exfoliates while hydrating and moisturizing the skin with glycerin and hyaluronic acid.
Ingredients: Aqua (Water), Lactic Acid, Glycerin, Pentylene Glycol, Propanediol, Sodium Hyaluronate Crosspolymer, Tasmannia Lanceolata Fruit/Leaf Extract, Acacia Senegal Gum, Xanthan Gum, Isoceteth-20, Trisodium Ethylenediamine Disuccinate, Sodium Hydroxide, Ethylhexylglycerin, 1,2-Hexanediol, Caprylyl Glycol.
The Ordinary Lactic Acid 10% + HA
The Ordinary Lactic Acid 10% + HA contains a 10% concentration of lactic acid to exfoliate the skin. It contains a purified Tasmanian pepperberry derivative which helps calm irritation and sensitivity that comes along with direct acids like lactic acid.
This serum also contains moisturizing glycerin and sodium hyaluronate crosspolymer to hydrate and plump the skin.
This is a mild exfoliating acid that helps to brighten the skin and even out skin tone while improving skin clarity. If your skin does not build a tolerance to this 10% formula and you continue to experience irritation, redness, and stinging, you may want to consider The Ordinary Lactic Acid 5% + HA or The Ordinary Mandelic Acid 10% + HA, which are gentler exfoliating AHA formulas.
Ingredients: Aqua (Water), Lactic Acid, Glycerin, Pentylene Glycol, Propanediol, Sodium Hydroxide, Sodium Hyaluronate Crosspolymer, Tasmannia Lanceolata Fruit/Leaf Extract, Acacia Senegal Gum, Xanthan Gum, Isoceteth-20, Trisodium Ethylenediamine Disuccinate, Ethylhexylglycerin, 1,2-Hexanediol, Caprylyl Glycol.
The Ordinary Lactic Acid 5% + HA vs The Ordinary Lactic Acid 10% + HA
Both The Ordinary Lactic Acid 5% + HA and The Ordinary Lactic Acid 10% + HA are effective exfoliating alpha hydroxy acid treatments. The Ordinary Lactic Acid 5% + HA is a great choice for beginners and those with sensitive skin. I see more immediate results with The Ordinary Lactic Acid 10% + HA, but you choose 5% or 10% based on your skin type and skin concerns.
The serums are very similar in appearance. The Ordinary Lactic Acid 10% + HA (on the right) is slightly darker in shade than The Ordinary Lactic Acid 5% + HA.
The Ordinary Lactic Acid serums can be used with water-based niacinamide serums like The Ordinary Niacinamide 10% + Zinc 1%. Niacinamide provides additional skin barrier support, making it a great choice to pair with lactic acid.
The Ordinary lactic acid serums are leave-on products and should not be washed off the skin.
Apply a product after The Ordinary lactic acid that complements its formula, like skin-barrier protecting The Ordinary Niacinamide 10% + Zinc 1% or hydrating The Ordinary Hyaluronic Acid 2% + B5.
The Ordinary lactic acid serums should be used no more than once a day. A few times a week will be optimal for most.
Yes, you can use The Ordinary lactic acid serums with The Ordinary Hyaluronic Acid 2% + B5. These serums work well together, as the hyaluronic acid will replenish hydration and moisture, and support a healthy skin barrier.
Using retinol and alpha hydroxy acids like lactic acid together can cause irritation and redness. Additionally, the variance in pH between the two may compromise product effectiveness. Consider using The Ordinary lactic acid serums and The Ordinary retinol/retinoids on different days or times of the day.
Related Post: The Ordinary Anti-Aging Skincare Review
Final Thoughts on The Ordinary Lactic Acid Serums
Even though these The Ordinary lactic acid serums are affordable and provide noticeable results, in general, The Ordinary suggests indirect (non-acid) forms of facial exfoliation instead of direct acids due to potential inflammation and sensitivity from acid use.
If you are interested in indirect forms of exfoliation, please check out The Ordinary’s sister brand NIOD’s Non-Acid Acid Precursor.
Still, I think that if you are looking for mild peeling formulations for under $10 each, these lactic acid chemical exfoliants from The Ordinary are some of the best available.
Thanks for reading!