How To Use The Ordinary Lactic Acid

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The Ordinary is a beloved brand that produces quality, no-fuss skincare at a low price in a (mostly) cruelty-free manner.

They offer two lactic acid serums: Lactic Acid 5% + HA  and No products found.. As one of their most popular products, lactic acid promises to ease texture and increase the brightness of your skin.

While The Ordinary makes fantastic products, it can be difficult to figure out how to use them and which are right for you.

In this article, we’ll look at how to use The Ordinary Lactic Acid.

Never fret because we’ve got all the information you need to implement this new acid into your skincare routine!


What Is Lactic Acid?

Lactic Acid

Before we get into how to use The Ordinary Lactic Acid, let’s talk about what it is.

Lactic acid is an alpha hydroxy acid that exfoliates the skin and removes dead skin cells. 

After your skin goes through the shedding process, it’ll reveal brighter and smoother-looking skin. It can also reduce signs of inflammation and sensitivity.

The benefits don’t stop there.

Lactic acid can improve uneven skin tone, skin texture, dark spots, and acne scarring, and it can also reduce the look of fine lines and wrinkles.

The Ordinary Lactic Acid serum is on the gentler side. It contains Tasmanian Pepperberry, which helps reduce the irritation commonly associated with acid use.

Lactic acid can even help with blackheads on a superficial level. 

What Skin Types Can Benefit From Lactic Acid?

Lactic acid is a great serum for most skin types.

It is a good choice for oily or acne-prone skin, as it can help with clogged pores and reduce the impact of acne scarring.

Because of its moisturizing properties, Lactic Acid can also be used on dry skin types. While it will exfoliate your skin, it shouldn’t dry you out or cause excessive peeling.

If you have sensitive skin and want to give lactic acid a try, you may want to use a lighter concentration. Do your research and patch test on your neck or upper forearm before using any product on your face. 

Lactic acid can be irritating on sensitive skin. If your skin is extremely sensitive, easily irritated, or compromised, do not use this product.

How To Use The Ordinary Lactic Acid

The Ordinary 5% Lactic Acid

Let’s discuss how to use The Ordinary Lactic Acid + HA serum.

As mentioned above, The Ordinary offers two formulas: Lactic Acid 5% + HA  and No products found..

The only difference is the strength of the lactic acid concentration.

Start Low

It is recommended that beginners or people with sensitive skin use the 5% formula to start.

Sun Protection!

Because lactic acid is an AHA, it can cause an increase in sun sensitivity and a higher chance of burning.

Night Application

This serum should be added to your nighttime routine, and you should implement sunscreen into your daytime routine. 

The Ordinary Lactic Acid + HA serum should be used at night, after toners but before moisturizer. 


You can use it every day, but it is recommended that you slowly introduce it to your routine. 

Aim to use it every other day, or three times a week, to start. Once your skin builds a tolerance, you can increase use.

Test Test Test!

Do not forget to patch test your product on your neck or forearm before applying it to your face. If irritation, burning, itching, redness, or blisters occur, do not use this product.

How To Dilute Lactic Acid

If you have sensitive skin or are new to lactic acid, you can dilute it with other products in your skincare routine.

The Ordinary Lactic Acid + HA serum can be mixed with other serums, such as their No products found. or their Niacinamide 10% + Zinc 1%  solution.

You can also mix it with your moisturizer.

For extra hydration, try a moisturizer with hyaluronic acid.

What Products Should I Avoid Mixing With Lactic Acid?

Because lactic acid is an alpha hydroxy acid, it can easily irritate when mixed with certain acids.

Combining your lactic acid serum with products containing these ingredients can result in irritation or reduce the efficiency of your products.


Retinol is used to increase cell turnover while removing dead skin cells. Because the two products do similar things, it isn’t recommended to mix retinol with lactic acid.

This is because there is a possibility of overdoing it and irritating your skin, causing redness or burning.

Another reason you should not mix lactic acid with retinol is due to their varying pH balances. Retinol has a higher pH balance than lactic acid and, when combined, renders it ineffective.

To include them both in your skincare routine, use the products on alternate nights.

Vitamin C

Vitamin C is an unstable acid, and its pH balance can be thrown off balance if mixed with lactic acid. This would render both products ineffective.

As well, Vitamin C is an ascorbic acid that works best at 3.5 pH. The Ordinary Lactic Acid serum has a pH balance of 3.6 – 3.8. 

Because these pH balances are so close, it may not put the effectiveness of the products at risk; however, you may experience irritation, burning, redness, or peeling.

If you wish to use both products in your skincare routine, apply your Vitamin C serum in the morning and your lactic acid at night, or use them on alternate nights.

AHAs and BHAs

The rule of thumb when it comes to lactic acid is to avoid most other acids or exfoliants unless it’s something your skin can handle.

AHAs and BHAs are strong exfoliants and, when mixed, can irritate your skin or cause redness.

This means that you should avoid mixing your serum with acids such as salicylic acid, glycolic acid, or any benzoyl peroxide treatments.


Peptides have a low pH of lactic acid. When combined with a direct acid, it can compromise the effectiveness of the peptide product, rendering it useless. 

The Ordinary does not recommend the combination of their Lactic Acid + HA serum and their Buffet + Copper Peptides 1% solution  or their Buffet solution . They also advise that their Lactic Acid serum not mix with their EUK 134 0.1% serum.


When diving into Lactic Acid solutions, start low! Stick to the 5% at first, and dilute as needed. When you’re ready, jump to the 10%. And don’t overdo the acids and exfoliants in your routine.

Good luck!

The Ordinary Lactic Acid 5% + HA 1 oz/ 30 mL For Exfoliating
The Ordinary Lactic Acid 5% + HA 1 oz/ 30 mL For Exfoliating
The Ordinary is born to disallow commodity to be disguised as ingenuity
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Written by Kayla Young

Kayla is the founder of LuxeLuminous. She has worked professionally in the tanning industry for years. She has been interested in esthetics since childhood, and has tried every hair, skin, and makeup product ever produced (more or less).