The Complete Guide To Using Lactic Acid

Acids are the best ingredients in skincare for the sole reason that they work great, give instant results, and can have a transformational effect on the skin.

However, there seems to be a lot of misconception floating around the internet when it comes to using acids, layering them properly, combining them with the right products to boost the effects, as well as which acid can help you with your particular skin concern.

Not every acid works for everything, so you need to know which one to choose to effectively tackle your skin concerns.

Lactic acid is one of those acids that many people claim works for everything when this is simply not the case. So today, I will give you the “complete guide” to using lactic acid and transform your skin with this great ingredient.


NB: I can show you how to never have acne again. If you have acne and want it gone, read this message.

What Is Lactic Acid?

Lactic acid is an exfoliating acid that belongs to the alpha-hydroxy acid (AHA) family. This ingredient is derived from sour milk or sugar-rich foods and it is a water-soluble substance that possesses larger molecules than other AHAs such as glycolic acid.

Due to its large molecules, lactic acid won’t penetrate deeper into the skin and will instead work on the surface, which leads to a lighter degree of exfoliation that is more suitable for sensitive skin types.

What Does Lactic Acid Do To The Skin?

The Complete Guide To Using Lactic Acid

Lactic acid is a well-known part of the skin’s natural moisturizing complex, therefore it can efficiently moisturize the skin. Lactic acid is naturally present in the gut and skin and it also contributes to the cell cycle in human keratinocytes (the skin cells).

Besides this, lactic acid can successfully acidify the skin, which means that when our skin is exposed to more alkaline environments that can have a negative effect on the epidermis, lactic acid can effectively bring the pH level of the skin back to normal.

Besides this, here are a few other benefits of lactic acid on the skin:

What Percentage Of Lactic Acid Is Most Effective?

Lactic acid is one of those gentler alpha-hydroxy acids, however, overusing this ingredient in higher concentrations can still lead to potential skin irritation. However…

The most effective percentage of lactic acid in an at-home treatment is anywhere between 5% for more sensitive skin types or 10% for more resilient skin types.

Additionally, lactic acid like all other exfoliating acids works best at a lower pH and the optimal pH level for an effective lactic acid treatment should be anywhere around 3.5-4.0.

How To Start Using Lactic Acid?

As with all chemical exfoliants, it is important to start introducing lactic acid into your skincare routine slowly and always opt for a lower concentration when first starting out.

Depending on the formula, initial tingling is pretty normal, especially if your skin is dehydrated or super sensitive, however, if this initial tingling becomes uncomfortable burning, this may mean that the product is too strong for you, therefore, you should wash it off and opt for something else instead.

Additionally, make sure to always follow up with a high SPF in the morning as lactic acid can make your skin sensitive to the sun.

Can You Use Lactic Acid If You Have Milk Allergy?

Can You Use Lactic Acid If You Have Milk Allergy

Due to lactic acid being derived from milk products, you might be thinking that it is related to lactose (which is a type of glucose found in milk).

However, lactic acid that goes into your skincare products won’t affect you if you are lactose intolerant because this type of lactic acid is synthetically produced.

But, if you are truly allergic to milk and you get the most severe reactions such as hives, shortness of breath, etc, then you should definitely have a little chat with your health provider before using lactic acid products.

On the other hand, it is always helpful to test a product somewhere in a small area like the inside on your wrist or behind your ear.

Especially with products such as The Ordinary Lactic Acid that cost around $10, even if you are sensitive to it or an allergic reaction happens, you can always give it to someone that might benefit from it.

Is It Okay To Use Lactic Acid Every Day?

No, it is definitely not okay to exfoliate every day, no matter how low the concentration of your product is or how mild the formula is.

Additionally, our skin doesn’t need daily exfoliation because the mature cells that sit tightly packed on the surface of your skin are a part of what’s called NMFs or natural moisturizing factors, therefore, they play an important role in helping your skin retain moisture.

Exfoliating daily, and thus constantly removing these mature cells may potentially damage your skin barrier and lead to irritation, sensitivity, and all sorts of skin problems.

Therefore, be mindful about exfoliation as this is a practice that happens regularly in a good skincare routine, but exfoliating daily is just excessive and your skin doesn’t need it.

Should You Moisturize After Lactic Acid?

Yes, you should always moisturize after any type of exfoliation you do.

Lactic acid naturally moisturizes the skin, however, once it’s absorbed into the skin, you still want to use something a little heavier and create that nice, occlusive barrier that will help your skin retain moisture.

Can You Combine Lactic Acid With Other Actives?

Lactic acid is still a strong exfoliant on its own, so combining it with other active ingredients is really unnecessary because this can potentially increase redness, irritations, and sun sensitivity.

Combining lactic acid with other actives isn’t a good idea. A good solution to this would be to alternate your actives and use them on different days.

What Should You Not Use Lactic Acid With?

What Should You Not Use Lactic Acid With

If you have sensitive skin, you should not be using lactic acid with other alpha-hydroxy acids such as glycolic or mandelic acid as well as beta-hydroxy acid such as salicylic acid.

However, the same rule doesn’t apply when you purchase a product that contains a blend of different AHAs as this is a properly formulated product with the right percentage of acids to complement each other in the formula.

Using a decent concentration of lactic acid and following it up with a decent concentration of glycolic acid, for example, will most definitely lead to unwanted irritation and sensitivity.

Additionally, you should also avoid combining lactic acid with retinol because of the potential irritation and sensitivity it can cause on the skin. If you are already using lactic acid on sensitive skin, it is best to keep these two apart.

Is Lactic Acid Good For Acne?

Lactic acid is not a good treatment for acne.

While mild exfoliation can always help the skin, you will definitely need a stronger ingredient such as salicylic acid or benzoyl peroxide to eliminate breakouts.

Lactic acid is a good exfoliator and may have a mild effect on soothing inflamed pimples. Still, there are many more useful treatments out there for this particular skin concern, so if you plan on incorporating lactic acid for this sole reason, this will not yield any significant results.

Can Lactic Acid Cause Breakouts?

Yes, lactic acid can cause breakouts.

Like all exfoliating acids, lactic acid is considered to be an “active” and what these actives do is they can speed up cellular turnover and push the gunk that’s inside the pore to the surface of the skin.

This means that what was going to become a pimple in a few weeks will come out on the surface sooner than that.

This is called a “purging period” and is very common when using actives, so if you start getting some mild breakouts while using lactic acid, this is not something you should be afraid of.

However, if this turns into a bigger concern such as severe breakouts, or inflamed cystic acne, you should definitely stop using the product and seek professional advice.

Can You Mix Lactic Acid With Other Ingredients?

Can You Mix Glycolic Acid With Lactic Acid?

Can You Mix Niacinamide With Lactic Acid?

5 Best Lactic Acid Products

Here are some excellent lactic acid products with different price points you should take a look at:

The Inkey List – Lactic Acid Serum

The Inkey List is a new and revolutionary skincare brand that is often compared to The Ordinary due to their ridiculously low prices and great product quality.

Their lactic acid serum is a gentle blend of naturally derived acids from milk and fruit sugars and what I love about it is that the product has a short list of straight-to-the-point ingredients.

This serum is a very gentle exfoliant, super-suitable for sensitive skin and it also contains 1% hyaluronic acid for extra hydration.

The Ordinary – Lactic Acid 5%

The Ordinary - Lactic Acid 5%

This was by far my favorite lactic acid product before the Inkey List stepped on the dancefloor and now I have to make a comparison review between the two.

Anyhow, this one is a super-gentle lactic acid exfoliant, very suitable for sensitive and acne-prone skin types with an additional 2% of hyaluronic acid for an extra hydration boost.

The Ordinary – Lactic Acid 10%

The Ordinary - Lactic Acid 10%

My skin loved the 5% version, however, the 10% was a completely different story for me. Since I enjoyed using the milder version, I thought I should step up my game and try to take on the bigger sister instead. I wanted even better results, so who can blame me for that?

But, little did I know my skin would immediately start rebelling against this decision. My skin broke out very badly after using this product and I have been avoiding it ever since. It still has a place on my shelfie, but it’s not going anywhere near my skin anytime soon.

I added it to this list because many people seem to enjoy this product and my skin’s reaction seems to be falling in the category of “isolated incidents” when you take a look at the customer reviews on this product.

So, I am not writing off the fact that I might have done something wrong with this product, but anyhow, it’s here. Let me know in the comments if you have had a similar experience with the 10% lactic acid. I would love to know.

Paula’s Choice – Smoothing Treatment 10% AHA

Paula's Choice Advanced Smoothing Treatment AHA 10%

I’ve already mentioned this product in my guide to using glycolic acid, but since it’s a blend of exfoliating acids and I briefly touched on this earlier, I will mention it again.

This product isn’t the best option for beginners, however, my skin liked it, and I also suggested it to my beloved mother, who also enjoyed using it.

It’s great for mature skin types as it has a blend of several alpha hydroxy acids, including glycolic, lactic, and malic acid. It works to rejuvenate the skin and minimize fine lines and wrinkles.

It is excellent to be followed up with low percentage retinol such as the Barrier Repair Moisturizer or the Retinol + Bakuchiol Treatment for amazing anti-aging benefits.

This is what I mean when I say that using a properly formulated product that contains multiple exfoliating acids is totally fine, however, you should never go ahead and use one lactic acid product and follow it up with another salicylic acid or glycolic acid product, for example.

Biossance – Squalane Lactic Acid Resurfacing Night Serum

Biossance - Squalane Lactic Acid Resurfacing Night Serum

I don’t have this product and I have never tried it, however, it comfortably sits in my CultBeauty cart, waiting for this global pandemic to end so it can be on its way to me (because, delays, ugh).

I have heard some great reviews on this product, and while I am not really impressed with several ingredients on the bottom, I am willing to forgive and try it out.

So I will be updating this post and obviously give you a proper, detailed review once that happens.

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