The best vitamin C serums for men

Two numbers, and only one of them gets printed

Every vitamin C serum on the shelf leads with a percentage. Almost none of them publish the second figure, and without it the first one is not interpretable.

L-ascorbic acid is only absorbed by skin below roughly pH 3.5. Above that it exists in an ionized form that does not cross the skin barrier. So a serum at 20 per cent formulated at pH 4 delivers less than one at 10 per cent at pH 3.2 - and you cannot tell which you are holding unless the maker says.

What this page ranks on

1. Published pH. First, because it decides whether the percentage means anything. One of the three publishes it.
2. Published concentration, in the useful band. 10 to 20 per cent. Higher is not better here, and that is a real finding rather than a hedge.
3. Stabilizers on the published list. Ferulic acid and vitamin E alongside L-ascorbic is the combination with the best evidence behind it, and both are checkable on an ingredient list.
4. What else is in it. An acidic serum costs you barrier; ceramides put it back. Alcohol high on the list costs you more.

Published figures, side by side

The pick: Paula's Choice C15 Super Booster

Fifteen per cent L-ascorbic acid at a published pH of 3.1 to 3.5. That is the only product in this category that tells you both halves of the specification, and it is why it wins without much argument.

Fifteen per cent is also the concentration most of the research on topical vitamin C actually uses, and the published list carries ferulic acid and vitamin E alongside it - the combination shown to stabilize L-ascorbic acid and improve its antioxidant effect rather than just sitting in the bottle as marketing.

The honest cons. Twenty milliliters is the smallest container here, which matters because vitamin C is a use-it-or-lose-it product - it oxidizes on a clock whatever the packaging. Neither the ferulic nor the vitamin E percentage is published, only their presence. And it costs several times the CeraVe for the same active.

For reactive skin: CeraVe Skin Renewing

Ten per cent L-ascorbic acid with all three ceramides published by name - NP, AP and EOP - plus hyaluronic acid and panthenol, in a full 26-item published list. CeraVe also publishes it as free of added fragrance, allergy-tested, non-comedogenic and paraben-free.

The ceramides are the reason to pick it. An acidic serum is a mild insult to the skin barrier; a formula that rebuilds the barrier in the same step is doing something the others are not, and on skin that reacts to actives that matters more than two extra percentage points of vitamin C.

The honest cons. No published pH, which on a water-based L-ascorbic serum is exactly the figure you want. Alcohol denat. is sixth on the published list, which is high for dry or reactive skin and sits oddly against the rest of the formula. CeraVe does not publish the container size on its own page. And 10 per cent is the slowest-acting concentration here.

The strongest one, and why it is the skip

The Ordinary publishes 23 per cent L-ascorbic acid - the highest here - in an anhydrous, water-free base. Water-free is genuinely clever: L-ascorbic acid degrades in water, so removing the water keeps the active stable in the bottle rather than quietly oxidizing.

It is the named skip for a first purchase for two reasons, and The Ordinary publishes both of them itself. The texture is granular, because the powder is suspended rather than dissolved. And a tingling sensation is to be expected - stated plainly on the product page, which is more honesty than this category usually offers.

The third reason is ours: 23 per cent is past the point where more concentration buys more benefit. Above roughly 20 per cent the research flattens while irritation keeps rising, so the biggest number on the shelf is not the best product on it.

The product that makes it worth using

Vitamin C is an antioxidant. It works alongside sunscreen against daytime damage, which means using it without sunscreen is spending money on the smaller half of the job.

EltaMD UV Clear is on this page for that reason: it publishes zinc oxide at 9 per cent, octinoxate at 7.5 per cent and niacinamide at 5 per cent, which is an unusually complete disclosure for a sunscreen. The sunscreen roundup ranks the field, and the mineral-versus-chemical comparison covers why that particular product is a hybrid rather than the pure mineral it is often taken for.

Using it without wasting it

• Morning, on clean dry skin, before moisturizer. Then sunscreen over the top - the layering order is here.
• A few drops, not a pipette. More does not absorb; it oxidizes on your face.
• Not at the same time as retinol. Vitamin C in the morning, retinol at night. Both at once is how people decide they cannot tolerate actives.
• Watch the color. Clear or pale straw is fine; amber or brown means oxidized. Replace it rather than finishing it.
• Store it away from light and heat. Not on a sunny windowsill, and not in a steamy shower.
• Give it eight to twelve weeks. Tone changes are slow, and almost every verdict on this category gets delivered at week two.