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What Are Skin Acids and How Do You Use Them? A Definitive Guide

April 18, 2020

What Are Skin Acids and How Do You Use Them? A Definitive Guide

Skin acids are some of the most powerful active ingredients in skin care. They have the power to erase blemishes, fade dark spots, lessen fine lines and deliver intense hydration almost instantly.

But, each acid has its own benefits. Knowing the differences between these molecules will help you choose the right one for your skin. From oily to dry, acne-prone to sensitive we’ve compiled a comprehensive skin acid guide below. We’ve also created a cheat sheet breaking down the most common skin care acids, and what they can do for you.

What are Skin Acids?

Skin acids include both humectant or exfoliating active ingredients. An active is an ingredient that causes physiologic changes in one of the skin layers that is measurable both scientifically and visually.

  • Some skin acids provide your skin with a targeted boost of nutrients or hydration. 
  • Many also speed up cell turnover. Cell turnover is the process in which the skin produces new skin cells from the lowest layer of the epidermis to the top and eventually shed off the skin. 
  • Other skin acids help dissolve the bonds that hold dead skin cells together, allowing old cells to slough off more easily. These skin acids essentially help you get new skin quicker.

Common Skin Acids in Skin Care

Two of the most common types of acids in skin care are alpha hydroxy acids and beta hydroxy acids. These two groups encompass the majority of the actives you’ll find in skin care. But, there are many more to be aware of too!

Read on to learn more about the different types of acids and how to incorporate them into your skincare routine.

1. AHAs or Alpha Hydroxy Acid

AHAs are water-soluble compounds, often used as exfoliants. Alpha hydroxy acids are a class of chemical compounds that can be either naturally occurring or synthetic. 

AHAs offer chemical exfoliation as an alternative to manual exfoliation, working by dissolving the bonds between skin cells to allow the removal of dead cells resulting in a smoother skin surface.

Thanks to their exfoliative properties, AHAs target sun spots, pigmentation, unevenness, fine lines and wrinkles. Many are derived from organic sugars, with glycolic acid and lactic acid being the most common.

Glycolic Acid

Glycolic acid is an AHA derived from sugarcane and sugary plants. This skin acid  gently dissolves dead skin. It helps with lightening dark spots, reducing fine lines, and smoothing skin's texture. It's effective in pretty much any form. Glycolic acid is great for people with oily skin, but anyone can benefit from regular use.

Lactic Acid

Lactic acid is another AHA. It's derived from milk. so it has a moisturizing element that the other exfoliating acids lack. This makes it perfect for reducing hyperpigmentation and fine lines in those with sensitive skin.

Malic Acid

Malic acid is a gentle AHA, naturally found in apples and pears. It's perfect for people with acne-prone skin as it can help open pores and clear out sebum.

Tartaric Acid

Tartaric acid is found naturally in many plants and fruits. This skin acid is great for smoothing out the texture of the skin.

Citric Acid

Citric acid is derived from citrus fruits. It is considered an AHA mostly, but some versions are classified as BHAs.  Citric acid is a strong antioxidant, ideal for those with sun damage or fighting the early signs of aging.

2. BHAs or Beta Hydroxy Acids

Beta hydroxy acids are also chemical exfoliators, but work best on oily skin that is prone to acne and blackheads. BHAs are oil-soluble, meaning they can penetrate clogged pores to deeply cleanse skin.

BHAs not only exfoliate the top layer of skin, but penetrate deeply blocked pores. They clean up oil glands, dissolving the accumulation of sebum and dead skin that leads to breakouts and blackheads. The most popular BHA in skincare is salicylic acid, used for acne.

Salicylic Acid

Salicylic acid loosens dead skin cells to relieve clogged pores and blackheads. It also reduces bacterial growth on skin’s surface and in oil glands. Salicylic acid is effective in almost any form and is best for people with oily and acne prone skin but can also be used by people with normal skin who have the occasional break out. 

3. Gluconolactone

Gluconolactone is a polyhydroxy acid or PHA. PHAs are a gentler class of exfoliant than AHAs or BHAs. Gluconolactone is effective without the redness, peeling, and sensitivity that comes with heavier-duty acids. But, it also doesn't penetrate as deep as they do.

4. Retinoic Acid

Retinoic acid is what retinoids and other derivatives of vitamin A turn into when applied to the skin. Retinoic acid boosts the amount of collagen your body makes, plumping skin and reducing fine lines and wrinkles. This skin acid improves skin texture and evenness. 

5. Hyaluronic Acid

Hyaluronic acid is a humectant, meaning it helps skin attract and retain moisture. This skin acid helps to strengthen the barrier of the skin so that its softer, smoother and appears more plump. Hyaluronic acid boosts skin vitality and vibrance making it perfect for fighting the signs of aging. Although called an acid, it is not exfoliative or harsh. Hyaluronic acid is tolerated well by all skin types.

6. L-Ascorbic Acid

L-Ascorbic acid is a synthetic version of vitamin C. This skin acid is an antioxidant that reduces fine lines and fights free-radicals as well as acting as a brightening agent. Most skin types can benefit from adding Vitamin C/L-Ascorbic acid into their skin care regimen.

7. Ferulic Acid

Ferulic acid is another anti-aging, free-radical fighting skin care superstar. Ferulic acid is great for fighting sun damage and those looking to reduce fine lines and wrinkles.

8. Acetic Acid

Acetic acid is vinegar. Although not recommended to use alone, gentler apple cider vinegar can be paired with malic acid to tone the face.

9. Azelaic Acid

Azelaic acid is most commonly found in prescription skin care treatments for acne and rosacea. Azelaic acid decreases inflammation and redness as well as a breakout busting antibacterial.

10. Fatty Acids

Fatty acids are found in oils. These are not exfoliating or harsh acids like AHAs and BHAs. Fatty acids hold hydrating and nourishing properties for skin.

Oleic Acid

Oleic acid is high in almond oil and olive oil. Oleic acids create a moisturizing seal on the skin. This skin acid is ideal for very dry skin.

Linoleic Acid

Linoleic acid is a fatty acid with a much lighter consistency. This one is better for people with oily or acne prone skin. Linoleic-rich oils include maracuja, grapeseed and sea buckthorn oil.

Lipoic Acid

Lipoic acid, or more specifically alpha lipoic acid, is said to be the universal antioxidant because it is both fat and water soluble. It works as an anti-aging ingredient that is anti-inflammatory and fights free-radicals. Foods like broccoli and spinach are high in lipoic acid.

How to Use Skin Acids in Your Skin Care Routine

Because skin acids change the skin on a chemical level, they have an almost instantly noticeable effect on the appearance of skin. This occurs by sloughing off the outer skin layer and making it visibly brighter. Skin acids also reduce the visible effects of ultraviolet damage, decrease collagen degradation and help restore the skin’s barrier.

  1. Start Slow

It’s important to introduce skin acids into your skin care routine slowly if you’ve never used them before, so start with once a week and increase your frequency to three to four times a week, skipping a day in between uses (salicylic acid, however, can be used daily). 

  1. Avoid Mixing with Harsh Actives

Be mindful of any other active ingredients in your product line-up. Using too many actives at once can cause an imbalance in the skin, resulting breakouts or irritation. Try to avoid using vitamin C or retinol immediately after any other skin acid, allowing a single active ingredient to work at a time, reducing the risk causing reactions. 

  1. Always Wear Sunscreen

And because acids remove the top layer of skin, they can make your skin more sensitive so always use a sunscreen spray as the last step in your shin care routine during the day.  


Common Skin Acids Cheat Sheet

Skin acid

What it does

Best for


Exfoliates, reduces fine lines and dark spots, evens skin texture

All skin types


Exfoliates, clears pores, treats breakouts

Combination skin and oily skin 


Hydrates and plumps dry skin

All skin types


Anti-inflammatory, prevents UV damage, stimulates collagen, brightens

All skin types


Enhances retinoids, fights free radical damage, protects collagen

All skin types


Speeds up cell renewal, balances skin pH

Hyperpigmented skin and sensitive skin 

You may be weary of adding skin acids into your skincare routine if you’ve never used them before, especially if you have sensitive skin. But skin acids are powerful active ingredients that fight off serious skin care woes like hyperpigmentation, sun spots, fine lines, wrinkles, dryness and breakouts. 

From Alpha hydroxy acids (AHAs) and beta hydroxy acids (BHAs) to salicylic acid, glycolic and hyaluronic acid, there’s a hard-working superstar skin acid for every type of skin. These skincare acids can be used for smoothing, making pores look smaller and removing surface dryness. They work just as well at making the skin look brighter. And, let’s not forget their ability to fight breakouts and smooth bumps. 

If you’re not already using a skin acid as a part of your skin care regimen, it’s time to step up your product game!