Vitamin C Serum: Three Forms of Vitamin C, Plus Fragrance — and How to Tell If It Has Gone Off

Vitamin C Serum — $20.00, 1 fl oz. The best-value product in our skincare range.

It contains three forms of vitamin C

• L-Ascorbic Acid — the pure, most-studied form
• 3-Glyceryl Ascorbate — a derivative
• Magnesium Ascorbyl Phosphate — a more stable derivative

Plus Ferulic Acid, which is commonly included alongside vitamin C because it helps stabilise it.

Using multiple forms is a sensible approach — pure L-ascorbic acid is the most researched but the least stable, and the derivatives are gentler and keep better. No percentages are given, so we cannot tell you the strength, and we will not estimate it.

Vitamin C goes off, and you can see it happen

This is the practical thing nobody tells you. L-ascorbic acid oxidises on exposure to air, light and heat. As it does, the serum turns yellow, then orange, then brown.

A brown or dark orange vitamin C serum has oxidised and should be thrown away. It is not doing what you bought it for, and oxidised vitamin C can be irritating.

To slow it down:

• Keep the cap tightly closed
• Store it somewhere cool and dark — not on a sunny windowsill, not in a steamy shower
• Some people keep vitamin C in the fridge, and it genuinely helps
• Use it within a few months of opening

A slight yellow tint is normal. Brown is not.

It contains fragrance

Listed near the end of the ingredient list: Fragrance.

If you have sensitive or reactive skin, fragrance in a leave-on facial product is the single ingredient most worth avoiding. Our 10% Niacinamide Serum carries a fragrance-free badge; this one does not. That may decide it for you.

"Avoid sun exposure after application" — what that means

Our directions say this, and it is worth explaining rather than leaving as a bare instruction. Vitamin C is an antioxidant and is generally used in the morning because it complements sun protection — but a fresh acidic serum on skin going straight into strong sun is not ideal.

The practical version: apply it, let it absorb, then moisturiser, then sunscreen. Do not apply it and walk straight outside. And wear sunscreen regardless — that advice does not change.

The rest of the formula

Water, Propanediol, L-Ascorbic Acid, Sorbitan Oleate Decylglucoside Crosspolymer, Glycerin, Rice Extract, Calendula Flower Extract, Chamomile Flower Extract, 3-Glyceryl Ascorbate, Magnesium Ascorbyl Phosphate, Jackfruit Extract, Imperata Cylindrica Root Extract, Ferulic Acid, Xanthan Gum, Phenoxyethanol, Ethylhexylglycerin, Fragrance, Sodium Gluconate.

One note: calendula and chamomile are both in the daisy family. If you have a ragweed or daisy-family allergy, those are the ingredients to be aware of.

Badges: vegan, cruelty-free, paraben-free, sulfate-free, silicone-free, phthalate-free, mineral-oil-free, alcohol-free, gluten-free.

How to use it

A small amount on clean, dry skin, massaged gently until absorbed. Morning. Do not use it in the same session as the retinol serum — see the layering guide.

What it claims

A brighter complexion and a more even-looking skin tone. Cosmetic, appearance-level claims. It does not treat hyperpigmentation or melasma as conditions, does not remove dark spots permanently, and "collagen-boosting" in a cosmetic context means the appearance of firmness — not a measured change in your skin's collagen.

For external use only. Avoid contact with eyes. Discontinue use if irritation occurs. If you have very sensitive skin, patch test first — L-ascorbic acid is acidic and can sting.