Niacinamide or vitamin C: which serum and what percentage?
People search this as “niacinamide vs vitamin c serum which percentage to use” · updated 2026-08
Short answer
Vitamin C (L-ascorbic acid 10-15%) is an antioxidant best used in the morning for brightness and sun-damage protection. Niacinamide (5%) helps with oil control, pores and barrier repair, and suits morning or night. Higher percentages are not better — 10% niacinamide commonly irritates, and vitamin C above 20% is unstable.
- Start with one active at a time and give it 8-12 weeks.
- Vitamin C degrades with light and air — opaque, airtight packaging matters.
- They can be layered; the old claim that they cancel each other out is outdated.
Which one for your concern
| Concern | Better pick | Percentage |
|---|---|---|
| Dullness, sun damage | Vitamin C | 10-15% L-ascorbic acid |
| Oiliness, large pores | Niacinamide | 5% |
| Post-acne marks | Either, or both | Niacinamide 5% + Vit C 10% |
| Sensitive skin | Niacinamide | 2-4% |
Label checks
- Ingredient position: an active listed near the end is present in a token amount.
- pH matters for L-ascorbic acid (below 3.5) — derivatives are gentler but weaker.
- Airless pump or dark glass for vitamin C; a clear dropper bottle oxidises fast.
- Patch test on the inner forearm for two days before using on the face.
Common follow-up questions
Can I use both in the same routine?
Yes. A common approach is vitamin C in the morning before sunscreen and niacinamide at night, or layering them with a minute's gap.
Is this medical advice?
No. This is general product-spec information. For persistent acne, pigmentation or reactions, see a dermatologist.