The Ultimate Guide to Acids in Skincare: Types, Benefits & How to Use Them Safely

In skincare, “acids” are common ingredients used to exfoliate, brighten, and smooth the skin. Though the term might seem scary at first, acids are actually great for achieving clear and healthy skin. The trick is knowing which ones suit your skin type and how to use them without causing irritation or damage.

In this blog post, I will explore the most common acids in skincare, how they work, and how to choose the right one for your skin.

The first step to deciding which acid works for you is to determine what your skin type is (your can learn about that HERE). The second step is to know what your skin concerns are and use the right acid that suits you.

What are acids in skincare?

To simplify one can say that acids are active ingredients that target specific skin concerns such as acne, hyper pigmentation, fine lines, and texture.

Most skincare acids work by exfoliating the skin—removing dead skin cells from the surface to reveal fresher, more even-toned skin underneath. But there are also hydrating acids.

Exfoliating acids generally fall into three main categories:

• Alpha Hydroxy Acids (AHAs)
• Beta Hydroxy Acids (BHAs)
• Polyhydroxy Acids (PHAs)

Each group of acids has unique properties and benefits for the skin. There is an acid for every skin type, it is just a matter of finding the right one.

Alpha Hydroxy Acids (AHAs)

AHAs are water-soluble acids derived from fruit, milk, or sugar. They are primarily known for their exfoliating properties and are ideal for people with normal to dry or sun-damaged skin. They also help to improve skin texture, tone, and hydration.

The most common types of AHAs:

Glycolic Acid

Glycolic acid is one of the most popular and effective AHAs. It has a small molecular size, allowing it to penetrate deep into the skin to exfoliate and brighten.

• Benefits: Helps fade hyper pigmentation, hydrates, improves skin texture, and stimulates collagen production.
• Best for: Normal to dry skin, aging skin, uneven skin tone.

Lactic Acid

• Lactic acid is derived from milk and has a larger molecular size than glycolic acid, making it gentler on the skin compared to Glycolic acid.
• Benefits: Exfoliates while hydrating and brightening the skin.
• Best for: Sensitive skin, dry skin, and those new to acids.

Mandelic Acid

• What it does: Mandelic acid is an AHA with an even larger molecular structure, which means it penetrates the skin more slowly and causes even less irritation.
• Benefits: Helps with acne, hyper pigmentation, and fine lines while being suitable for sensitive or darker skin tones prone to post-inflammatory hyper pigmentation.
• Best for: Acne-prone or sensitive skin.

Benefits of AHAs:

• Exfoliate the skin for smoother texture
• Improve the appearance of fine lines and wrinkles
• Fade dark spots and even out skin tone
• Increase hydration by improving moisture retention
• combating signs of sun damage
• Enhance absorption of other skin care products

How to Use AHAs:

When starting to use AHAs it is always best to start slow and gentle. All skin’s are different and some people can tolerate a high concentration of AHAs whilst others find lower concentrations to work the best. Today you can find AHAs in almost any type of skincare like cleansers, toners, serums and masks. This doesn’t mean you should be using them all.

Stick to one (I prefer toner or serum) and use that 2-3 times a week and then gradually increase. Always use sunscreen when you are using acids since your skin becomes more sensitive to UV damage.

Beta Hydroxy Acids (BHAs)

BHAs, unlike AHAs, are oil-soluble, which means they can penetrate deeper into the pores. This makes them an excellent choice for treating acne and blackheads.

The most common BHA:

Salicylic Acid

• Salicylic acid is the most common and widely used BHA in skincare. Its oil-soluble properties allow it to unclog pores, exfoliate dead skin cells, and reduce inflammation.
• Benefits: Helps treat and prevent acne, clears blackheads and whiteheads, and minimizes oil production.
• Best for: Oily, acne-prone skin, and those with blackheads or clogged pores.

Benefits of BHAs:

• Unclog pores and prevent acne
• Exfoliate inside the pore to clear blackheads
• Reduce inflammation and redness
• Control excess oil production

How to Use BHAs:

As with AHAs, BHAs are also found in a lot of different skincare products like cleansers, toners and serums. You start using BHAs gently and then increasing how often you use it. I would start with 2-3 times a week and then gradually increase. Make sure that you wear sunscreen after using acids on your skin.

Polyhydroxy Acids (PHAs)

PHAs are a newer class of acids similar to AHAs but with a larger molecular structure, making them much gentler on the skin. They are ideal for those with very sensitive skin or conditions like rosacea, as they exfoliate without causing irritation.

Common Types of PHAs:

Gluconolactone

• Gluconolactone gently exfoliates the surface of the skin without disrupting the moisture barrier.
• Benefits: Improves skin texture, hydrates, and provides antioxidant benefits.
• Best for: Sensitive or reactive skin, or those with rosacea.

Lactobionic Acid

• Lactobionic acid not only exfoliates but also acts as a humectant, drawing moisture into the skin.
• Benefits: Helps with skin texture and hydration while strengthening the skin’s moisture barrier.
• Best for: Dry, sensitive skin, and anyone looking to maintain a healthy moisture balance.

Benefits of PHAs:

• Gentle exfoliation suitable for sensitive skin
• Strengthen the skin’s moisture barrier
• Provide antioxidant benefits to protect against free radical damage
• Reduce fine lines and improve skin texture

How to Use PHAs:

PHAs can also be found in toners, serums, and moisturizers. Because they are so gentle, they can be used daily and are less likely to cause irritation or sun sensitivity compared to AHAs and BHAs.

How to Choose the Right Acid for Your Skin Type

When incorporating acids into your skincare routine, it’s important to choose the right type of acid based on your specific skin concerns and tolerance level. As always it is better to start with lower concentration and a more gentle acid. The goal is to find an acid that works, not an acid that causes damages to your skin. Even though you want a quick result that is not what you are going to get. Acids should be used over time and be incorporated into a working skincare routine.

For dry, normal or Mature Skin:

• Opt for AHAs like glycolic or lactic acid to exfoliate dead skin and improve hydration while targeting fine lines and uneven skin tone.
• PHAs are also a great choice for gentle exfoliation without compromising moisture.

For Oily or Acne-Prone Skin:

• BHAs like salicylic acid are your best bet. They penetrate deep into the pores, helping to clear out sebum and reduce breakouts.
• If you’re dealing with both acne and sensitivity, consider incorporating a mild PHA for gentle exfoliation.

For Sensitive Skin:

• Stick to PHAs or gentler AHAs like lactic or mandelic acid. These acids provide the benefits of exfoliation without the risk of irritation.

For Combination Skin:

• You can mix and match acids. Use BHAs on the oilier, more acne-prone areas (like your T-zone) and AHAs or PHAs on the drier, more sensitive parts of your face.

Tips for Safely Using Acids in Skincare

• Start slow: If you’re new to acids, introduce them into your routine gradually, starting with 2-3 times per week.
• Patch test: Always patch test new acid products on a small area of your skin to ensure you don’t have any reaction.
• Moisturize: Acids can sometimes disrupt your skin barrier, so it’s important to follow up with a hydrating moisturizer to replenish moisture.
• Sun protection: Acids can make your skin more sensitive to the sun, so always apply sunscreen (SPF 30 or higher) when using them.

Conclusion

Acids are powerful ingredients that can transform your skin if you use them correctly. Whether you’re looking to treat acne, smooth out fine lines, or boost your skin’s glow, there’s an acid out there to suit your needs. Just remember to start slowly, choose the right acid for your skin type, and always prioritize hydration and sun protection when incorporating acids into your skincare routine.

Product tips

AHAs

COSRX – AHA/BHA Clarifying Treatment Toner

COSRX – AHA 7 Whitehead Power Liquid

SOME BY MI – AHA, BHA, PHA 30 Days Miracle Toner

Isntree – Chestnut AHA 8% Clear Essence

BHAs

COSRX – BHA Blackhead Power Liquid

Anua – BHA 2% Gentle Exfoliating Toner

SKIN 1004 – Madagascar Centella Tea-trica BHA Foam

APLB – Salicylic Acid BHA Arbutin Ampoule Serum

PHAs

AXIS – Y – PHA Resurfacing Glow Peel

KLAVUU – Green Pearlsation PHA Calming Serum

NEOGEN – Dermalogy Green Tea Moist PHA Gauze Peeling

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