PHA vs BHA: which should you choose?

What does BHA do?

BHA means beta hydroxy acid. These acids dissolve in oil and work inside pores, helping remove dead skin and sebum, the oily substance your skin produces. Salicylic acid is the most common BHA in skincare. Its ability to remove oils inside pores makes it a useful choice for blackheads and whiteheads, rather than just surface roughness. You can find salicylic acid in cleansers, toners, serums and moisturizers. Choose the product for the concern you want to address, because the bathroom does not need an alphabet filing system.1

What can you compare confidently?

How should you start using an exfoliant?

1. 1Review your current routine first. Retinol, prescription retinoid creams and benzoyl peroxide can make skin more sensitive or cause peeling. Adding exfoliation can worsen dryness or breakouts.
2. 2Follow the product's application directions and warnings. Do not invent a contact time or use a rinse off product as a leave on treatment.
3. 3Choose frequency by the product and your skin's response. More aggressive exfoliation generally needs less frequent use; twice daily use is not a target you have to reach.
4. 4Apply moisturizer immediately after exfoliating, and use SPF 30 or higher sunscreen on your face every day.

Facial acids need regular use and time to improve skin's appearance. Salicylic acid can be used twice daily by many people, but your product's directions and tolerance should determine your schedule. There is no ingredient specific PHA schedule or fixed results deadline to give for this comparison.1

Who should be careful?

Dry or sensitive skin often needs mild exfoliation rather than an aggressive treatment. Avoid strong exfoliation if you have darker skin or develop dark marks after skin injuries: aggressive exfoliation can increase pigmentation. Never exfoliate sunburned skin or areas with open cuts or wounds. Stop exfoliating if your skin becomes red and irritated. A dermatologist can help you decide whether exfoliation is suitable, particularly if your skin already stings or burns after products.2

How do AHA, BHA and PHA compare?

AHA means alpha hydroxy acid. AHAs dissolve in water and loosen the bonds holding surface skin cells together, while BHAs also work on oils inside pores. Glycolic and lactic acid are common AHAs; lactic acid is one of the gentler options for sensitive skin. PHA's position alongside these categories remains unresolved in this comparison. The initials save space on a bottle, but they do not finish the shopping decision.1

For an AHA, the degree of exfoliation depends on the acid, concentration, pH and other ingredients, not just the percentage. Leave on AHA products are generally applied at night. AHAs can increase sun sensitivity, so use sunscreen, wear protective clothing and limit sun exposure during use and for a week afterwards.34