Use thoughtfully
Both are AHAs — choose one
Combining offers little benefit and meaningfully more irritation.
How to use
Pick one and use 2–3 nights per week.
Two ingredients. One considered answer — with the reasoning behind it. Switch ingredients to refine.
Basic mode shown. Advanced analysis includes barrier-stress scoring, sequencing, redundancy, and skin-type considerations.
Combining offers little benefit and meaningfully more irritation.
Pick one and use 2–3 nights per week.
Glycolic Acid and Lactic Acid act through different cellular pathways. Understanding those mechanisms — rather than the marketing claims — is what determines whether they belong in the same routine.
Stacked in the same routine, this pairing measurably raises the cumulative load on the barrier. The effect is gradual — and easy to miss until it appears.
Separate by routine — one in the morning, the other in the evening — or alternate days. Reduce frequency rather than concentration.
Sensitive, rosacea-prone, or recently compromised skin requires more conservative sequencing. Resilient, well-acclimated skin has more latitude — but the same principles apply.
Synthesized from peer-reviewed dermatology and cosmetic-chemistry literature — including studies on barrier function, pH stability, and ingredient interaction. Reviewed against formulator guidance.
Pick one and use 2–3 nights per week.
Establish tolerance to Glycolic Acid and Lactic Acid individually before combining. Always pair active routines with daily SPF.
Sensitive, rosacea-prone, or recently compromised skin should sequence more conservatively. Resilient, well-acclimated skin has more latitude.
Not ideal for beginners. Build tolerance to each ingredient on its own before combining.
Generally considered safe during pregnancy and breastfeeding. Always confirm with your clinician.
Reflects current dermatological consensus and peer-reviewed cosmetic chemistry literature.
Risk and evidence ratings reflect published clinical data where available, and formulator consensus where it is not. Individual response varies — patch test before introducing a new active.
Use thoughtfully
Too much, too fast
Brief pH consideration
Effective when separated
Separate by routine
Compounded exfoliation
A quiet reminder