AHA (Alpha Hydroxy Acid)

What it does

Smallest AHA; penetrates deeply to exfoliate and brighten.

Commonly found in: toners, peels, serums

• Oily skin — Effective deep clean.
• Dry skin — Can over-dry — use weekly.
• Acne-prone skin — Clears dead skin from pores.

• Sensitive skin — Can sting and irritate.
• Damaged or compromised barrier — Acids worsen broken-skin irritation — pause until healed.
• Heavy sun exposure — Daily SPF 30+ is non-negotiable while using exfoliating acids.

Common conflicts & pairings

Click any pairing to see the full compatibility report.

• Avoid
  AHA (Alpha Hydroxy Acid) + Retinol — Prescription tretinoin is significantly stronger than OTC retinol. Combining it with AHAs can cause severe irritation, peeling, hyperpigmentation, and barrier breakdown.
• Caution
  AHA (Alpha Hydroxy Acid) + Retinol — Retinol accelerates cell turnover; AHAs chemically exfoliate the top skin layer. Stacking them on the same night can compromise the barrier, cause flaking, redness, and stinging.
• Caution
  AHA (Alpha Hydroxy Acid) + BHA (Salicylic Acid) — AHA works on surface skin cells, BHA penetrates oily pores. Some formulas combine them intentionally (e.g. Paula's Choice BHA) but DIY layering two separate acid products usually over-exfoliates, especially on sensitive skin.