- Beta hydroxy acid (BHA), is a lipid-soluble ingredient best suited for exfoliating oily skin.
- This ingredient penetrates deep into the skin to help clean and unclog skin pores and hair follicles.
- BHA exfoliants are available over-the-counter (OTC) or via prescription.
- Exfoliants containing BHA are safe to use for all skin tones and types and do not increase the skin’s sensitivity to the sun.
Exfoliation is the process of removing oil, dirt and dead skin cells from the skin leaving it fresh and with a renewed, healthier surface.
Exfoliating products are made with different agents and ingredients to combat a multitude of skin conditions and to better exfoliate certain types of skin. An exfoliant containing BHA as the active ingredient is one type that is effective for exfoliating skin, especially so for those with oily skin.
What is BHA?
Beta hydroxy acid is a nonabrasive acid derived from salicin, a chemical similar in nature to aspirin. Salicin is primarily extracted from willow bark, but may also originate from wintergreen and sweet birch.
When added to OTC and prescription exfoliants, creams, lotions and peels, BHA functions as an exfoliator, anti-inflammatory, anti-aging and antimicrobial agent.
BHA exfoliants are commonly made with salicylic acid (SA), a type of BHA. Other forms of BHA are tropic acid, malic acid and less frequently, citric acid.
How does it work?
BHA is desmolytic in structure, possessing the ability to loosen and break the attachment between cells. This process causes the formation of new cells while exfoliating the epidermis, or outer layer of skin.
BHA is also lipid-soluble, which means it can more easily bypass the fats and oils in and on your skin. This ability enables BHAs to penetrate the surface of the skin to counter the formation of comedones (acne lesions, such as blackheads and whiteheads) by entering the skin’s pores to break up and remove dead skin cells, oils and bacteria—all the debris that helps comedones form.
BHA vs. AHA exfoliants
Alpha hydroxy acid (AHA) exfoliants are water-soluble. AHAs, such as lactic acid and glycolic acid, are humectants, retaining and preserving the skin’s moisture.
AHA exfoliants thin the outermost layer of the epidermis by peeling away dead skin cells and revealing the healthier skin beneath. The process also helps prevent the formation of comedones and skin blemishes. In addition, AHA exfoliants stimulate collagen production to tighten skin and reduce wrinkles and fine lines.
In general, AHA exfoliants are a good choice for those with dry skin, as their use will not cause further dryness. BHA exfoliants are best used for oily skin, as the lipid-soluble BHA can penetrate the epidermis through the oil and fatty tissue to deeply exfoliate and remove dead skin and oil.
Benefits of BHA Exfoliants
The properties of BHA help treat and prevent a number of skin issues. The antimicrobial, anti-inflammatory and anti-aging nature of BHA exfoliants remove the oil, skin cells and debris responsible for causing and exacerbating common skin conditions.
The accumulation of dead skin cells may lead to pores becoming clogged and prevent sebum, an oily substance that helps skin stay hydrated, from releasing. This leads to a buildup of sebum in the sebaceous glands, the glands responsible for producing sebum, and the formation of comedones, such as whiteheads, blackheads and pimples – a condition called acne vulgaris.
BHA’s lipid solubility means the chemical can concentrate in the oily sebaceous glands. In doing so, the material blocking the pores and hair follicles are removed and the pores are reopened.
Bacteria feed on fatty acids produced during the overproduction of sebum, which further contributes to the formation of acne lesions. However, as BHA is antibacterial, it also fights the bacteria that contribute to the formation of acne.
Wrinkles and fine lines
Aging, genetics and damage from the sun’s ultraviolet rays cause the skin to lose its elasticity, leading to the formation of wrinkles, or rhytids, and fine lines.
BHA exfoliants, in the derivative forms of beta-lipohydroxy acid (LHA) and sodium salicylate (SS), aid in reducing fine lines and wrinkles. While the exact reasoning for this isn’t yet understood, it is believed that it is the turnover of skin in the exfoliating process that contributes to BHA’s ability to reduce wrinkles and fine lines.
Postinflammatory hyperpigmentation (PIH), is the darkening of the skin. While PIH affects individuals of all skin types, it more commonly impacts individuals with darker skin tones.
Inflammation or injury to the skin can cause PIH. It may also present as a side effect of certain skin care products and cosmetic treatments.
Although chemical exfoliation with SA does not have a significant impact on reducing PIH, it does effectively reduce redness, dryness, scaliness and oily skin associated with a PIH flareup.
Rosacea is an inflammatory skin disease that causes erythema, or skin redness, and visible blood vessels. It may also cause red bumps to appear on the skin, leading to uneven texture, and cause the skin to thicken or dry out. Rosacea can also enlarge the sebaceous glands, causing bumps on the skin and increased sebum production.
BHA exfoliants possess anti-inflammatory properties that can help treat the erythema caused by rosacea. In contrast to other topical exfoliants, BHA is less likely to exacerbate irritation caused by a rosacea breakout.
Milia are small cysts filled with a protein called keratin which, along with dead skin cells, become trapped beneath the surface of the skin. The underlying cause of milia isn’t known, but its appearance may sometimes be caused by using harsh skin care products.
BHA exfoliants can go a long way toward preventing the buildup of dead skin cells or softening or reducing the number of milia already present on the skin.
Psoriasis is an inflammatory disorder that most commonly affects the scalp and presents as thick red plaques and silver scales. Psoriasis may also be visible on the neck, hairline, forehead and ears.
BHA exfoliants, in the form of SA, have a keratolytic effect on psoriasis, in which skin is thinned and keratins are softened to make plaques and lesions less apparent.
Treating psoriasis with a BHA exfoliant is more effective when combined with other topicals because BHA, in the form of SA, helps other cosmetic products better penetrate the skin.
Dandruff is an itchy condition that leads to flaky and scaly skin on the scalp. A more extreme type of dandruff, seborrheic dermatitis, or SD, may occur in areas of the body with a high concentration of sebaceous glands. Where dandruff is relatively mild, SD is inflammatory, reddening the skin in addition to flaking.
The keratolytic effect of BHA exfoliants is an effective treatment for dandruff. When used on symptoms of SD, BHA has been demonstrated to reduce scales, redness, itching, dryness and discomfort when used as part of a consistent skin care routine.
Warts present themselves on the epidermis and may manifest in a variety of forms and can be skin-colored or dark and flat, rough or smooth.
BHA exfoliants are a first-line treatment in removing warts. The keratolytic nature of SA removes the outer layer of the epidermis that is infected by HPV, the cause of warts.
BHA Exfoliant vs. Exfoliating Scrubs
Physical or mechanical exfoliating scrubs are abrasive, which means they physically remove skin. This process can disrupt the skin barrier and cause a loss of moisture. Additionally, scrubs made with particularly rough or gritty ingredients, such as ground fruit pits or shells, can cause microtearing of the epidermis, resulting in a rough and uneven texture.
In contrast, BHA exfoliants are chemical exfoliants. When compared to exfoliating scrubs, BHA exfoliants are less harsh and cause fewer, milder side effects, if any. BHA exfoliants also penetrate deeper into the skin as opposed to the surface-level exfoliation provided by a physical scrub, which tend to be considered more harsh and irritating to the skin than their chemical alternatives.
How to Choose a BHA Exfoliant for Your Skin Type
In addition to BHA, which serves as an active ingredient, BHA exfoliants can also include a number of other ingredients designed to treat a given skin concern.
When looking for the best BHA exfoliant for your skin, look at the ingredients list to ensure you choose one that meets your needs.
Ingredients to look for
- BHA exfoliants for acne often include fruit extracts for their antioxidative properties, which help protect your cells from damage, and niacinamide, an anti-aging ingredient that helps improve skin elasticity.
- Licorice, green tea, aloe vera and other botanicals are added to BHA exfoliants to aid in treating rosacea.
- Licorice root extract is antimicrobial, antiviral, anti-inflammatory and anticarcinogenic, and useful in treating PIH.
- Glycerin, a humectant, is commonly included in BHA exfoliants to hydrate and moisturize the skin.
Certain combinations of ingredients can also complicate or irritate the skin condition you’re looking to treat. When buying an exfoliating BHA product, avoid:
- Combining SA and benzoyl peroxide; together these two ingredients may increase the efficacy of a cosmetic product, particularly one used to treat acne. However, some people may develop skin irritation by using both ingredients at the same time.
- Combining SA with other active ingredients, such as retinol, can also lead to skin irritation. This is especially important for those with sensitive skin or who suffer from rosacea.
- Denatured alcohols derived from petroleum-based ingredients can cause dry skin in some individuals. Such alcohols are alcohol-denat, ethanol and isopropyl alcohol.
AHA and BHA together
BHAs may be combined with AHAs—as ingredients in the same product, or as separate products used at different times in your skin care routine—for a more intensive exfoliation.
While you may be tempted to use both types of exfoliants one after the other, begin by alternating usage of each product. If your skin is oily and you typically exfoliate with BHA in the morning, you can try using an AHA product at night.
Before incorporating both exfoliants into your skin care routine, experiment on your skin by using the newest product as a spot treatment.
The downsides of combining both AHA and BHA are the potential for causing your skin to become overly dry or irritated. If you begin to notice negative side effects as a result of using AHA and BHA together, consider:
- Using them on an alternating basis
- Reducing the concentration or strength of one or both exfoliants
- Reducing how much, or how often, you’re exfoliating
OTC BHA exfoliants are sold in concentrations ranging from 0.05–5%, although most OTC products are available in concentrations of 2% or lower. Stronger concentrations are available by prescription. Likewise, chemical peels, which offer stronger exfoliation, typically use SA in concentrations between 20–30%.
BHA exfoliants purchased OTC are strong enough to exfoliate your skin as part of your regular routine. They are also effective for mild to moderate acne. Conditions such as warts, psoriasis and hyperpigmentation may warrant using a prescription-strength BHA exfoliant tailored to treat your specific issue.
Who should avoid BHA exfoliants
While BHA exfoliants are mild enough to treat even sensitive skin, there are some individuals who should avoid using products made with BHA or its derivatives.
- BHA exfoliants with greater than 5% concentration should not be used in individuals with Fitzpatrick skin types IV–VI, or light brown, brown or black skin, without supervision or permission of a dermatologist, as higher concentrations of BHA can worsen skin conditions in these skin types.
- Cosmetic products containing BHA should be used sparingly on children, and not used on children under two years old.
- Using BHA on areas of the skin that are already irritated or infected may significantly worsen conditions.
Additionally, women who are pregnant or breastfeeding should consult a doctor prior to using BHA exfoliants. Individuals with an aspirin allergy, NSAID allergies, diabetes, kidney disease or liver disease should also avoid using BHA exfoliants.
How to Use a BHA Exfoliant
BHA exfoliants can be added to your skin care routine based on your desire to treat a given condition and your existing regimen.
For example, individuals with moderate to severe photodamage may use a 3-product skincare regimen:
- Massage a combination AHA/BHA exfoliant onto the skin; rinse and pat dry.
- Apply an anti-aging retinol serum to the same area.
- Apply sunscreen with SPF 50 or more prior to sun exposure and reapply as needed throughout the day.
BHA exfoliants tend to work best when there’s little to no existing material to pass through, including residue from other skin care products. As such, a BHA exfoliant should be one of the first products you use as part of your routine.
An example of a good skin care routine incorporating a BHA exfoliant is:
- Wash with a gentle cleanser; pat dry.
- Apply a toner with ingredients suited to your skin type and skin concern.
- Exfoliate with a BHA.
- Apply a moisturizer followed by sunscreen with SPF 50 or higher prior to sun exposure.
If you use any skin care serums, apply them prior to moisturizing.
When you first incorporate an exfoliant into your routine, try to use it no more than two or three times per week if you have normal or a combination of dry and oily skin. Those with sensitive skin shouldn’t use exfoliants more than once or twice per week. You may adjust or limit usage depending on your skin’s reaction.
A word about sun sensitivity
Studies have demonstrated that AHA increases the skin’s sensitivity to the sun’s ultraviolet radiation. As a result, individuals who use AHA without proper protection from the sun are subject to skin redness, photodamage and sunburn.
In contrast, BHA does not cause an increase in the skin’s sensitivity to UV radiation. It is recommended that BHA exfoliants be formulated in a way to avoid skin irritation and sensitivity to the sun, or to provide directions for proper sun protection in the event skin sensitivity to photodamage is increased.
With this in mind, the use of a BHA exfoliant should be followed by an application of sunscreen if the product containing BHA does not already provide sun protection.
DIY BHA Exfoliators
A DIY exfoliant can be made using a combination of household and natural ingredients, although balancing the acidity of a DIY solution can be difficult.
The safest exfoliating solution is a professionally-formulated cosmetic product. DIY BHA exfoliators, especially those using ingredients such as lemon and papaya, may increase your skin’s sensitivity.
Aspirin-based DIY BHA exfoliator
This DIY BHA face mask relies on the chemical similarities between aspirin and salicylic acid.
- Combine 1 tablespoon of baking soda with 1 cup of water; stir until the baking soda dissolves.
- In a dish, sprinkle the juice of one lemon over 12 uncoated aspirin tablets.
- Using the backside of a spoon, crush the aspirin and combine with the lemon juice to form a paste. Add lemon juice as needed.
- Apply the exfoliant to your face, avoiding the eye areas, and leave for 10 minutes.
- Remove the mask using a cotton ball soaked in the baking soda and water mixture.
Aspirin face masks can be used up to 2 times per week.
All-natural DIY BHA exfoliator
A number of fruits, such as papaya and pineapple, serve as natural sources of SA. As a result, you can make an all-natural DIY exfoliator without using aspirin tablets.
- Skin and slice a pineapple and papaya, removing the seeds from the latter.
- Blend both fruits to a pulp in a blender.
- Apply 2–4 ounces of the pulp to your face for 10 to 15 minutes, avoiding the eye area.
- Wash the pulp from your face; pat dry.
An all-natural exfoliator can be used 2–3 times per week.
BHA exfoliants are lipid-soluble and capable of penetrating deep into the epidermis and pores to break down and remove dead skin cells, oil and bacteria. As an exfoliating agent, BHA loosens the attachment between skin cells to shed the outer layer of the epidermis and trigger the formation of new skin cells.
As an anti-inflammatory, anti-aging and antimicrobial agent, BHA is effective in helping to treat a number of skin conditions without harm. In addition, BHA with a concentration of less than 5% is safe for all skin types and there are very few contraindications.
In contrast to AHA, BHA does not increase the skin’s sensitivity to sun damage. Still, sunscreens are recommended in skin care routines that include BHA exfoliants.
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