Vitamin C serum guide

Forms of vitamin C

L-ascorbic acid is the most researched but can sting and oxidise quickly. Derivatives like ascorbyl glucoside or magnesium ascorbyl phosphate are gentler and more stable.

Typical strengths: 10–15% for L-ascorbic acid, 2–10% for derivatives.

How to use

Apply in the morning on clean skin, followed by moisturizer and SPF. Start every other day for sensitive skin.

Store in a cool, dark place.

Troubleshooting

Orange or brown serum has oxidised. Stinging means reduce frequency or choose a derivative.

Track tone changes at eight to twelve weeks.

Choosing by skin type

Sensitive or dry skin often prefers derivatives or lower percentages in a creamy base, while oily or resilient skin may tolerate L-ascorbic acid in a lightweight serum.

If you notice stinging, check that you are not applying after an exfoliating acid, and consider using it every other day.

At a glance

Short on time? Here is the essence of vitamin c serum guide in a few lines.

Myth, reality and when to pause

Myth: A higher percentage is always better.

Reality: Stability, formulation and tolerance matter. A well-formulated lower strength can outperform a harsh one.

Frequently asked questions