Ingredient index
Retinol
The most studied over-the-counter retinoid; two conversion steps from retinoic acid.
What it can share a night with
| With | Verdict | Why |
|---|---|---|
| Salicylic acid | Alternate nights | Both increase turnover, and stacking them is the most common route to the stinging and flaking people mistake for sensitive skin. Alternate nights and the irritation usually resolves without dropping either. |
| Vitamin C | Use with care | Commonly repeated advice that they cannot be layered, which is weaker than it sounds. |
Sources
- Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety - Clinical Interventions in Agingsystematic review