The short answer
Retinol and salicylic acid are two of the most common “I want clearer skin” picks, and both ask a lot of the barrier when left on. Used in the same evening step they stack irritation: flaking, tightness, and the false conclusion that your skin “cannot handle actives.”
The library marks them as a do-not-layer pair for that reason. Congestion-prone skin often still wants both over a week — just not as a sandwich. Put leave-on BHA on nights you skip retinol, or use a salicylic cleanser that rinses off and keep retinol as the only leave-on active at night.
If you are mid-purge or mid-peel from starting retinol, freeze the BHA until skin feels boring again. Clearing pores can wait a fortnight; a stripped barrier takes longer to forgive.
Honest cosmetic-use guidance for home routines. Stop and seek a professional if you get swelling, blistering, or symptoms that worry you.
How to use both without stacking them
- Retinol nights: cleanse → dry skin → retinol → moisturiser. No leave-on BHA.
- BHA nights: leave-on salicylic acid → moisturiser. No retinol.
- Optional: salicylic acid as a short-contact cleanser on retinol nights if your skin stays comfortable — rinse thoroughly.
- Daily sunscreen is non-negotiable on both schedules.
