Zinc PCA vs Niacinamide, Honestly: Which One for Oily Skin — and Do You Need Both?

Search for zinc PCA vs niacinamide and most of what you find is written by companies that sell the raw ingredients or the serums. This one is written by a brand too: we make a gel with each, and nothing with both.

So this is the version with the sources attached: what each ingredient is, what was tested on people and what was only tested in a dish, whether you need both, what EU law says about zinc, and exactly what is in ours. If you only want the decision, skip to which is better for oily skin.

What niacinamide and zinc PCA are

• Niacinamide (also called nicotinamide) is a form of vitamin B3. It dissolves in water, so it works in light gels and serums, and it is one of the better-studied cosmetic ingredients. Our niacinamide gel guide covers the trials on tone and dark spots.
• Zinc PCA is the zinc salt of pyrrolidone carboxylic acid. PCA is part of the skin’s own natural moisturising factor, and its sodium salt, sodium PCA, is a common humectant. Binding zinc to it gives a zinc compound that dissolves in water, which is why it fits in a gel or a serum.

People compare the two because they so often arrive together. The best-known serum of this kind pairs 10% niacinamide with 1% zinc PCA, and the format has been widely copied. That makes it hard to tell which ingredient is doing the work — and it is the question the published research answers least well.

Zinc PCA vs niacinamide: what the evidence shows

Niacinamide: tested on people

The key paper is from 2006 and reports two separate trials of a moisturiser with 2% niacinamide. In Japan, 100 volunteers were split into two groups: 50 used the niacinamide moisturiser and 50 a placebo moisturiser for four weeks. The rate at which their skin produced oil was the same at the start, and significantly lower in the niacinamide group after two and four weeks.

In the United States, 30 Caucasian volunteers used it on one side of the face for six weeks. Here the result was mixed: the amount of oil sitting on the skin was significantly lower, but the rate of production was not. The authors’ own conclusion is cautious — niacinamide “may be effective”.

Both trials used 2%, which is less than the 5% in many moisturisers and far less than the 10% in popular serums. Nothing in this paper shows that a higher strength controls oil better.

Zinc PCA: tested in the lab

The claim you will read most often is that zinc blocks 5-alpha-reductase, the enzyme that converts testosterone into the form that drives the oil glands. It comes from a 1988 study in Paris. The researchers added zinc sulphate — not zinc PCA — to samples of human skin in a test tube, and the enzyme’s activity fell. They were careful about what that meant, writing that zinc could be useful “if this inhibition is confirmed in vivo”. We could not find a study that confirmed it on living skin with zinc PCA.

Zinc PCA itself was studied in 2012 by researchers employed by Ajinomoto, a Japanese ingredient manufacturer. In cultured human skin cells exposed to UVA, it reduced an enzyme that breaks down collagen and increased the cells’ production of type I collagen. The same paper notes that zinc PCA has long been used in cosmetics for its astringent and anti-microbial properties. All of it is cells in a dish, reported by a company in the ingredient business.

Zinc does have human evidence as a medicine. A 2020 analysis of the published trials concluded that zinc, taken by mouth or applied to the skin, reduced the number of inflamed spots in people with acne. In the same year a Cochrane review of topical treatments, including nicotinamide and zinc, judged most of the evidence to be of low or very low quality. Neither tells you what a cosmetic gel with zinc PCA does for shine.

Both together: one trial, as a medicine

The only trial we found that includes zinc PCA by name combined it with nicotinamide. In 2020, five teaching hospitals in Indonesia enrolled 140 people with moderate acne. Everyone used adapalene, a prescription retinoid; half added a cream containing nicotinamide, zinc PCA and an antibacterial agent, and half a placebo cream, twice a day for six weeks. The group using the combination cream had significantly fewer non-inflamed spots at the two-week check. The trial was funded by a pharmaceutical company, and it cannot separate the zinc from the niacinamide.

Which is better for oily skin?

On published human evidence for oil, niacinamide. It is the only one of the two shown to lower a measure of sebum in a controlled trial, and even that result was clearer in one population than the other.

Zinc PCA is a reasonable supporting ingredient with a plausible mechanism and a long record of use. It is not a proven oil regulator, and anyone who tells you it “switches off” sebum is quoting a test tube.

In practice the rest of the formula matters at least as much as the headline ingredient. An oil-free gel with good humectants can leave skin looking less shiny simply because it adds water without adding oil. A formula high in alcohol feels matte at first and can leave skin tight later. Read the whole ingredient list, not the front of the bottle.

Can you use zinc PCA and niacinamide together?

Yes. Nothing in the research suggests they interfere with each other, they are routinely formulated in the same product, and the 2020 trial that combined them found no significant difference in side effects from placebo at its two- and four-week checks.

Using both does not have to mean layering two moisturisers. One moisturiser step is enough for most skin. If you want both ingredients and own two products, use one in the morning and the other in the evening.

Is there an EU limit on zinc PCA?

Yes, indirectly. Annex III of the EU Cosmetics Regulation limits water-soluble zinc salts to 1%, calculated as zinc, in a finished product. Zinc PCA dissolves in water, so it falls under that entry. Zinc makes up about a fifth of zinc PCA by weight, which puts the ceiling at roughly 5% zinc PCA. Zinc oxide, the mineral sunscreen filter, is a different substance with its own rules.

What is in ours

Oil-Free Zinc Face Gel for Men

The Oil-Free Zinc Face Gel for Men has 21 ingredients. Aloe leaf juice comes first, in place of water, followed by glycerin, pentylene glycol, butylene glycol and betaine, which draw water into the skin. Zinc PCA is seventh, ahead of the fragrance. The manufacturer does not publish the percentage, so we do not state one. There are no oils in the formula and no alcohol (ethanol).

Three things worth knowing. It is listed for normal and dry skin that is prone to blemishes or dehydration, so think of it as a hydrating gel first and an oil-control product second. It contains fragrance (parfum, with limonene, linalool, geraniol and citral from natural essential oils). And “for men” describes the packaging and the scent, not the chemistry: nothing in the list is specific to male skin.

Niacinamide Gel Moisturiser

The Niacinamide Gel Moisturiser has 13 ingredients and states its strength: 5% niacinamide. Water is first, alcohol second and niacinamide third, so there is at least as much alcohol as niacinamide. That is what makes it dry down fast, and it is also why it may not suit skin that is dry or easily irritated. It has no oils, and it contains fragrance.

No product in our range contains both ingredients.

How to choose between them

• Shine, plus uneven tone or marks left by spots: the niacinamide gel. It has the better evidence for both, and sunscreen in the morning does as much for tone as any serum.
• Shiny but tight or dehydrated, or you avoid alcohol: the zinc gel. It is alcohol-free and built on humectants.
• You want both ingredients: one in the morning, the other in the evening, rather than layered together.
• Fragrance bothers your skin: neither. Both are scented; the Sensitive Skin Moisturiser, Fragrance Free has no parfum, and the fragrance-free edit lists the rest.
• Spots that are painful, deep or leave scars: see a doctor or dermatologist. A cosmetic is not an acne treatment.

Where to start

If oil is your main concern and your skin tolerates alcohol, start with the Niacinamide Gel Moisturiser: it is the ingredient with the human evidence. If your skin is shiny and tight at the same time, the Oil-Free Zinc Face Gel for Men is the gentler formula, whoever is using it. The rest of the men’s range and the edit for blemish-prone skin are built around the same light textures.

And if a product stings, or your skin feels tighter after two weeks than it did before, stop. Less shine is not worth a damaged barrier; our skin barrier guide explains how to tell.