BHA stands for Beta Hydroxy Acid. The best known example in skincare is Salicylic Acid. BHA is an oil-soluble chemical exfoliant that can penetrate deeper into the pores than water-soluble AHAs (Alpha Hydroxy Acids), to remove dead skin cells and reduce excess sebum production. BHA is also antibacterial and anti-inflammatory. It targets the bacteria that colonise pores and cause acne spots, so it’s a great option for oily, combination and congested skin.