Can you use retinol and vitamin C together?
Yes, just not at the same time. Most people get the best of both by using vitamin C in the morning and retinol at night.
Why split them
Pure vitamin C (L-ascorbic acid) works best at a low pH, and both can irritate when you're starting out. Layered together, the chance of stinging and redness goes up. Vitamin C also pairs well with sunscreen, which makes the morning its natural place.
Other combinations to keep apart
- Retinoids + AHA/BHA exfoliants: alternate nights.
- Benzoyl peroxide + retinol: can deactivate some retinoids. Use them at different times.
- Several strong acids at once: pick one per routine.
Fine together
- Niacinamide with almost anything.
- Hyaluronic acid, glycerin and ceramides with any active.