The hype about cosmetic acids and their presence in all kinds of skincare products is on the rise.
On one hand, this can be called a positive trend, as it shows that people understand the importance of regular exfoliation. But on the other hand, many people use cosmetic acids without knowing how they function and what risks they may pose when used incorrectly.
Besides, as not all acids are suitable for all skin types, another important question to look into is who can use these cosmetic ingredients safely!
Before using cosmetic acids it’s important to “meet them” and get to know them. This way you can have better control over your skincare routine and the products you use to improve your skin appearance.
There are two types of cosmetic acids: Alpha Hydroxy Acids (AHA) and Beta Hydroxy Acids (BHA). And while we delve deep into the topic of AHAs in a whole another blog post, this article focuses entirely on BHAs, their function, benefits, drawbacks, and safety.
Let’s get started!
What are beta hydroxy acids?
Beta Hydroxy Acids are active cosmetic ingredients that are naturally occurring in various plants. Even though they are from natural origin, they may be drying and as a result are frequently used as an ingredient in chemical peels. The degree of peeling is frequently dependent on the concentration and the duration of application of this ingredient.
That being said, evidence suggests the BHA concentration between 1-2% can ensure optimal skin results after long term use. 
There are different types of beta hydroxy acids  :
- Salicylic acid (also listed as salicylate, sodium salicylate, and willow extract)
- Beta hydroxybutanoic acid
- Tropic acid
- Trethocanic acid
The most commonly used BHA is salicylic acid, which can be found on its own or in combination with AHAs in different skincare products, including moisturizers, toners, and serums.
How betа hydroxy acids work?
BHAs and Alpha Hydroxy acids (AHAs) have similar benefits and uses, including treatment of fine lines and wrinkles, hyperpigmentation, improving skin texture and treatment of acne. 
That being said, according to the US Food and Drug Administration, the main differences between AHAs and BHAs are in terms of penetration and irritation. 
While AHAs are water soluble and penetrate only in the epidermis (top skin layer), BHAs are lipid-soluble, which enables them to penetrate deeper through the sebaceous follicles and directly influence the sebum production.
In addition, BHAs are less likely to cause skin irritation in contrast to AHAs (i.e. glycolic, lactic or malic acid).
Why are BHAs good for skin?
Pregnancy and breastfeeding: Topical use of glycolic and lactic acid (i.e. AHA), in lower concentrations, is considered safe to use during pregnancy and lactation. Discuss with your board-certified dermatologist prior to using skincare products during pregnancy.
Targeting dark marks: If your goal is to target stubborn dark marks, hyperpigmentation and melasma, AHAs reduce the appearance of hyperpigmentation and help to even out skin tone.
Targeting premature aging: Though AHAs and BHAs are both used to reduce the appearance of fine lines and wrinkles, AHAs have the added benefit of stimulating collagen production in the skin.
Combination of AHA and BHA: Can I use AHAs and BHAs together in the same product? Well yes you can! Some topicals contain a combination of both ingredients which help target both acne, shallow acne scars and hyperpigmentation.
Nighttime application: As mentioned above, AHAs and BHAs may increase sensitivity to sunlight and nighttime application is recommended.
Frequency of application: In general, when starting topicals, especially exfoliants it is recommended to start 2-3 times weekly and increase to nightly as tolerated. If you are using other topical or manual exfoliants, it is recommended to talk to your dermatologist to create a treatment plan and regimen to avoid skin irritation.
Evidence suggests that beta-hydroxy acids (particularly salicylic acid) may offer you various skin benefits when used consistently  :
- Even pigmentation and fading dark spots
- Less visible scars
- Reduced appearance of wrinkles, fine lines, and other signs of aging
- Better skin texture
- Stronger skin barriers
- Improved water-retention mechanism
- Balanced sebum production
- Softer skin
- Improved symptoms of keratosis, psoriasis, or other skin conditions related to keratin buildup
- Faded warts and calluses
- Reduced comedonal and inflammatory acne symptoms
- Reduce inflammation
What are the downsides of BHAs?
Generally, cosmetic products with beta hydroxy acids are considered safe when used in allowed concentrations (usually about 3% in leave-on products and 30% in rinse off products with salicylic acid). 
Although BHAs are less likely to cause skin irritation, photosensitivity, and DNA damage in comparison to their counterpart, AHAs, BHAs may still cause skin irritation and dryness, especially in individuals with dry, sensitive skin. 
Here are some downsides that shouldn’t be underestimated:
The use of BHAs may result in photosensitivity, increasing one’s risk for sunburns, pigmentation, and other UV-light related damage. For that reason, applying SPF (at least 30) when using products with acids is essential to prevent such damage.
If used in higher concentrations, these acids may lead to irritation symptoms, including burning, peeling, redness, swelling, or excessive dryness.
BHAs in drugstore skincare products can be found at different concentrations. Before reaching for such products, it’s important to seek advice from a board-certified dermatologist about the appropriate acid concentration and the suitability of such cosmetics for your skin.
Are beta hydroxy acids safe for all skin types?
It depends! As BHAs can trigger irritation and dryness, they should be used carefully by people with sensitive, reactive, and dry skin.
However, beta hydroxy acids can be effectively used in anti-acne therapies. For that reason, these cosmetic ingredients are highly suitable for people with comedogenic or inflammatory acne. In addition, they can be used for fading signs of aging and pigmentation in mature skin.
Besides, BHAs can be also suitable for people with keratosis, psoriasis, or another keratin-related skin condition.
That being said, everyone’s skin differs and not everyone’s skin fits a single category or skin type: oily, mature, sensitive, etc. In order to identify whether BHAs are suitable for your skin type, have a consultation with a board-certified dermatologist.