Lactic acid vs. glycolic acid vs. salicylic acid: which one is better for acne? 

Q & A with Dr. Carolina Fernandez Quiroga, Dermatologist

Table of Content:
What are Alpha Hydroxy Acids? | What are Beta Hydroxy Acids? | What is the difference between them? | Glycolic Acid Benefits, Skin Types and Precautions | Lactic Acid Benefits, Skin Types and Precautions | Salicylic Acid Benefits, Skin Types and Precautions | FAQ

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Glycolic acid and lactic acid are Alpha Hydroxy Acids (AHAs)¹, while salicylic acid is a Beta Hydroxy Acid (BHAs) and has higher acidity².

AHAs and BHAs are chemical exfoliants used in skincare products that help remove dead skin cells from the top layer of your skin.

What are Alpha Hydroxy Acids?

Alpha Hydroxy Acids (AHAs) are a group of plant-derived acids used in skincare products, including anti-aging products such as serums, creams, and chemical peels³.

• Glycolic acid (from sugar cane)
• Lactic acid (from lactose or other carbohydrates)
• Citric acid (from citrus fruits)
• Malic acid (from fruits)
• Tartaric acid (from grapes)⁴

Although there is extensive research on the benefits of AHAs, Glycolic and lactic acids are the most researched and used in skin care while also causing less irritation^5 6.

What are Beta Hydroxy Acids?

Beta Hydroxy Acids work as an exfoliant since they cause the cells of the outermost layer of the skin to shed, making room for the regrowth of new skin⁷. In addition to renewing cells, BHA reduces excess sebum and prevents pores from clogging.

Although there are a few different Beta Hydroxy Acids, only salicylic acid (or related ingredients such as salicylate, sodium salicylate) is used in the skincare industry.

What is the difference between Alpha Hydroxy Acids And Beta Hydroxy Acids when used?

The main difference between glycolic acid and lactic acid (AHAs) and salicylic acid (BHAs) is that glycolic acid and lactic acid are water-soluble⁸, while salicylic acid is oil-and-water soluble⁹. 

salicylic acid can penetrate a pore containing oily sebum and exfoliate the dead skin cells that build up inside the pore. 

“If you have dry skin, an AHA is recommended because it will be more gentle on your skin. If you have oily skin, a BHA is recommended because it will be more effective at penetrating pores and removing blemishes,” says Dr. Fernandez.

“The direct use of a salicylic solution is also not recommended for people with darker skin types (Fitzpatrick Types IV, V, VI) because it can cause hyperpigmentation on untreated skin. Furthermore, people applying a salicylic acid formulation should always use a broad spectrum sunscreen,” added Dr. Fernandez.

Lactic acid vs. glycolic acid vs. salicylic acid: the benefits, precautions and how to use them 

What is glycolic acid and what does it do? 

Glycolic acid is the most used of the AHAs because it improves the appearance of photodamaged skin, reduces fine lines and wrinkles, smooths uneven skin texture, and reduces hyperpigmentation^{10  11} .

The information on this image was obtained from these two sources:
https://onlinelibrary.wiley.com/doi/10.1046/j.1524-4725.2001.00234.x
https://link.springer.com/article/10.1007/s004030050212

What skin type Is glycolic acid best for?

“Glycolic acid is not recommended for people with sensitive, reactive or dry skin. Let’s remember that the appearance of spots on the skin is an all too frequent problem. Therefore, whenever acids are used, regardless of their concentration, sunscreen should be used.

Glycolic acid products can come in a wide range of concentrations, and it’s always a good idea to see a dermatologist if you’re using concentrations higher than 10%,” says Dr. Fernández.

Precautions when using glycolic acid

Dr. Fernandez recommends avoiding glycolic acid under the following circumstances:

• Avoid using too many glycolic acid-containing products at the same time
• Do not use it if you have recently had microdermabrasion or any treatment that removes the top layer of your skin
• Discontinue use while being at the beach or exposed to the sun
• Do not combine it with other acne medication or cosmetics before consulting with your dermatologist
• Do not use it at the same time as any laser treatments 
• Always use sunscreen when using glycolic acid
• If you wish to become pregnant, are pregnant or are breastfeeding, always consult your doctor before applying cosmetic products.

What is lactic acid and what does it do? 

Lactic acid is one of the most common AHAs in cosmetic products, such as over-the-counter chemical exfoliants and professional chemical peels.

Lactic acid is a type of AHA derived from milk, but it can also derive from fermented sugar-rich foods; it removes the top layers of dead skin cells and increases the skin’s thickness, promoting firmness¹⁴.

The information on this image was obtained from this source:
https://pubmed.ncbi.nlm.nih.gov/8784274/

What skin type is lactic acid best for?

“People with all skin types can use lactic acid; however, it is particularly recommended for sensitive, dry, and mature skin,” says Dr. Fernandez.

Precautions When Using lactic acid

“The precautions in the use of lactic acid are similar to glycolic acid, as in any product that performs peeling, avoid using similar products at the same time, avoid high concentrations, consult your dermatologist if you want to combine it with prescription products, or others exfoliants and always use sunscreen with a high SPF factor-like 50,” says Dr. Fernández.

What is salicylic acid and what does it do?

Salicylic acid is BHA that works as a chemical peel, and it has been widely used; it is originally derived from the bark of willow trees¹⁶. 

This ingredient has been widely used to address several skin problems, including acne, psoriasis, rough and bumpy skin (also known as keratosis pilaris), photodamage, and melasma¹⁷.

As part of a skincare routine for acne-prone skin, it can help leave your skin feeling softer and smoother because it supports the shedding of dead skin cells to reveal a healthy-looking complexion.

The information on this image was obtained from these two sources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4554394/
https://pubmed.ncbi.nlm.nih.gov/30972839/

What skin types is salicylic acid best for?

“Since salicylic acid is better lipid soluble, it can penetrate clogged pores, decreases sebum secretion, making it especially beneficial for those with oily or acne-prone skin. Always use sunscreen responsibly. Be careful not to use other exfoliants to avoid adverse reactions. When in doubt, always consult a doctor,” says Dr. Fernández.

Precautions when using salicylic acid

“The precautions on the use of salicylic acid are the same as mentioned above, avoid using the same ingredient on several products, stick to lower concentrations unless you are under medical supervision, and always use sunscreen with SPF 50. If you wish to become pregnant, are pregnant or are breastfeeding, always consult your doctor before applying cosmetic products. Do not use topical acids on children. Topical salicylic acid in children may cause side effects. Tell your doctor before putting any type of cosmetic product on a child’s skin,” says Dr. Fernandez.

FAQ about glycolic, lactic, and salicylic acids

Why should you use glycolic acid, lactic acid, or salicylic acid in your skin care routine for acne?

The skin is renewed approximately every 28 days, so the most superficial cells that are dead are shed naturally. However, certain circumstances, such as age, climate, indoor heating, air conditioning, stress, medication or health-related issues, can slow down the usual flaking phase.

When this happens, dead skin cells remain on the skin’s surface, making the complexion appear dull. In addition, a timely exfoliation helps skin care products penetrate the skin efficiently, so regular exfoliation is essential to a good skin care routine.

Can you use glycolic, lactic, and salicylic acids together?

Yes, if two of the ingredients are combined in the same product. It is not advisable to use different products with these ingredients in consecutive order. Glycolic and salicylic acids work well together. However, because you’re using twice the active exfoliating ingredients, it’s even more important to start slow and pay attention to any sensitivity that may occur.

What acids cannot be mixed in the skin?

AHAs and BHAs, such as Glycolic, Salicylic, and lactic acids, should never be used with vitamin C, which is also an acid. This nutrient is unstable, so by combining these ingredients the pH balance is lost and its effect on the skin is likely to be totally useless or cause irritation.

Which is more hydrating glycolic acid or lactic acid?

Lactic acid is recommended for people with dry, sensitive or mature skin. Through its exfoliating action, lactic acid is used to remove dead skin cells, brighten the complexion, and improve the appearance of fine lines. Unlike other acids, it is also moisturizing.

Are glycolic acid and lactic acid the same thing?

No, they are both Alpha Hydroxy acids which means they both work as exfoliants for the skin but they also have different properties.

Are glycolic, lactic and salicylic acid good for acne?

Yes, all three products can be used to combat acne, always keeping in mind the different skin types and adverse effects. If you’re still unsure about which acid is best for your skin—glycolic, salicylic, or lactic acid—consult a healthcare provider for guidance on the best course of action.

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