AHA/BHA

What are AHAs and BHAs? 

AHAs (Alpha Hydroxy Acids) and BHAs (Beta Hydroxy Acids) are a family of skin-refining acids that work to gently dissolve the bonds between dulling surface cells, supporting natural cellular turnover. AHAs, including Lactic and Glycolic Acid, are water-soluble and work on the skin's surface. BHAs – most notably Salicylic Acid – are oil-soluble and penetrate the pore. Together they form the Hydroxy Acid Complexes of The Refining Collection. 

What is the difference between AHAs and BHAs? 

AHAs are water-soluble and work primarily on the skin's surface, refining the appearance of texture, uneven tone, and dullness. BHAs are oil-soluble and penetrate deeper into the pore, making them effective for the appearance of congestion and excess sebum. Many RATIONALE formulations combine both for comprehensive skin-refining benefits. 

What do Hydroxy Acids do for skin? 

Hydroxy Acids support the skin's natural turnover, helping refine the appearance of texture, brighten dullness, address congestion, and maintain skin pH. With consistent use, they reveal a smoother, more radiant complexion. Within RATIONALE's Refining Collection, they sit alongside Peptides and are paired with skin-comforting ingredients to maintain barrier resilience while delivering visible refinement.

Which RATIONALE formulations contain AHAs and BHAs? 

Hydroxy Acids form the foundation of The Refining Collection, with #5 The Refining Serum as the hero formulation. They also feature in #5 The Refining GelCrème and #5 The Refining Cleanser. 

Are AHAs and BHAs safe for sensitive skin? 

Yes, when introduced gradually. RATIONALE Hydroxy Acid formulations are paired with skin-comforting actives to support tolerance across skin types. Sensitive skin types are encouraged to begin with two evenings per week and to layer with Nourishing formulations. Always pair Hydroxy Acid use with daily SPF to help support skin protection and recovery. 

How often should I use Hydroxy Acid formulations? 

We recommend introducing Hydroxy Acid formulations two to three evenings per week, gradually building to nightly use as tolerance develops. Always apply daily SPF the following morning, as Hydroxy Acids increase the skin's sensitivity to solar and environmental damage. For tailored guidance, consult our Client Services Team or a RATIONALE Skin Therapist.

Can I use AHAs/BHAs with retinol? 

Yes. The Refining Collection (Hydroxy Acids and Peptides) and The Rejuvenating Collection (Vitamin A) work in synergy within the PM Ritual. We recommend introducing one active at a time to assess tolerance, alternating evenings as you build, and always layering with Nourishing formulations to maintain barrier comfort. Daily SPF is essential when using either active.