The ABCs of AHAs and BHAs

Get to know your acids


What exactly are AHAs and BHAs?

Alpha-Hydroxy Acids (AHAs) are a group of plant and animal-derived acids used in a variety of skincare products, including anti-aging products, like serums, or concentrated treatments such as chemical peels.

Beta-Hydroxy Acids (BHAs) are organic compounds which, in skincare, penetrate the skin and unclog pores, which can help those with oily skin prone to breakouts.

The biggest difference between AHAs and BHAs is their lipid (oil) solubility. AHAs are water soluble and BHAs are oil soluble.

AHAs and BHAs both act as exfoliants, but BHAs are able to penetrate deeper into the skin and pores, and help trigger the exfoliation process of the dead skin cells that build up inside the pores and often cause acne.

AHAs and BHAs both act as exfoliants, but BHAs are able to penetrate deeper into the skin and pores and help trigger the exfoliation process.

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It has been claimed that BHAs are effective in reducing the appearance of fine lines and wrinkles and improving overall skin texture and acne scars without the occasional irritation associated with the use of low level AHAs and higher concentrations often found in acne products. These acids are overseen by the Food and Drug Administration for their concentration and pH levels. Remember, always use a mineral sunscreen when using AHAs and BHAs.

There are several different types of AHAs, including:

  • Glycolic Acid

Glycolic acid has the smallest molecules of all the AHAs. It is colorless, odorless, and water soluble. Glycolic acid is naturally derived from sugar cane but is synthetically produced by several manufacturers. Glycolic acid is commonly known for its use in cosmetic and haircare products.

  • Tartaric Acid

Tartaric acid is found in unripe grapes and is the primary active ingredient that gives wine its distinct taste. Commercially, tartaric acid is found as a white powder and is often used in the food industry to give foods a sour taste.

  • Citric Acid

The highest level of naturally occurring citric acid is found in oranges and lemons; however, it also occurs as part of the metabolic process in most living creatures. Citric acid is an antioxidant and also a natural preservative. It is often used in the food industry to add a sour taste to drinks and foods.

  • Malic Acid

Malic acid is found in several fruits and vegetables but is most associated with apples and cherries. Malic acid also occurs naturally as part of the metabolic process in humans and animals. It is often used to enhance flavors in beverages, candy, confections, and in medicinal products like lozenges.

  • Mandelic Acid

Mandelic acid is an AHA derived from bitter almond. Mandelic acid has antibacterial properties. It has been used medicinally as a treatment for urinary tract infections and as an oral antibiotic. It is also used cosmetically as an anti-aging and acne treatment.

What about Salicylic Acid?

A type of BHA, the natural form of Salicylic Acid is a chemical agent that can be obtained from fermentation of the bark of willow trees. It is an organic acid chemically similar, but not identical, to the active component of aspirin (acetylsalicylic acid) found in some chemical products today. Salicylic Acid is used in cosmetics, mostly acne care and anti-inflammatory products.

Salicylic Acid can also be used as an antidandruff agent, as well as for skin and hair conditioning, and is found in many personal care products including moisturizers, cleansers, shampoos, masks, and serums.

How does Salicylic Acid work on the skin?

Salicylic Acid has keratolytic and comedolytic properties, which eliminate dead cells and black heads, promote cell turn over, and prevent acne and wrinkles. The process is simple. It extracts desmosomal proteins which ensure the cohesion of epidermal cells in the skin. As a result, the cohesion of epidermal cells is lost, leading to exfoliation, thus promoting healthy skin. It also disrupts cellular junctions rather than breaking or lysing intercellular keratin filaments, promoting cellular turn over. 

What types of acne does Salicylic Acid work best on?

Due to its anti-inflammatory properties and its ability to removes superficial keratinized dead skin cells that are clogging pores, Salicylic Acid is especially effective against vulgaris acne. This is an inflammation and obstruction of pilosebaceous units (hair follicles and their accompanying sebaceous gland), caused by the pathogenic activity of Propionibacterium acne bacteria, which cause the formation of papules, pustules, nodules, and cysts.

Salicylic Acid can be used in all grades of acne but can achieve faster results in mild acne activity like grades one to three (papulo-pustules activity), versus grades four to five, which can take more then four months to re-establish balance.

If you have acne or are acne-prone, be sure to use foaming cleansers without sulfates at night to remove all residue of minerals, which prevents acne.

 How much Salicylic Acid should you use?

Ideal anti-acne treatments have the right formulation of actives and percentage in order to not damage the skin and respect its integrity. Most common anti-acne products contain 1-2% salicylic acid concentration, the maximum allowed in over the counter topical products.

Typical concentrations of Salicylic Acid used in dermatology and cosmetics:

Concentration            Uses

0.5%–10%                        Acne

3%–6%                           Hyperkeratotic disorders like psoriasis, ichthyoses, keratosis pilaris

5%–40%                          Warts, corns

20%–30%                       Superficial chemical peeling of face

50%                                  Actinic damage and pigmented lesions

Who should avoid using Salicylic Acid?

Those with skin that is extremely sensitive, including rosacea, should be careful when using salicylic acid as well as AHAs, unless recommended by a dermatologist or skin specialist.