Which niacinamide percentage should you use?

Niacinamide products now range from under 1 percent to 20 percent, and the number on the front of the bottle is often the main selling point. The research tells a quieter story: nearly every trial used 2 to 5 percent. This guide lists what each strength was tested for, what the safety tests covered, and how to choose. For the full overview of the ingredient, see what niacinamide does for your skin.

What each strength was tested for

This table gathers the strengths used in the trials read for this hub.

Strength	What it was tested for	Study
2 percent	Lower facial oil	2006, 100 Japanese adults over 4 weeks, and 30 white adults over 6 weeks
2 percent	Dry skin, water loss	2005, 28 people with eczema, cream twice a day for 4 or 8 weeks
2 percent	Skin fats, with 2 percent lotion twice a day for 4 weeks	Reported in a 2010 review
4 percent	Acne	1995, 76 people, gel twice a day for 8 weeks; 2013, 80 people, 8 weeks
4 percent	Pores, evenness, wrinkles	2007, 52 adults in Taiwan, 12 weeks
5 percent	Acne	2013, 60 women, gel for 8 weeks
5 percent	Red blotchiness, fine lines, spots, texture	2004 and 2005, 50 women each, 12 weeks
10 percent and higher	No trial found in the sources read for this guide	None

Every benefit on this list came from 2 to 5 percent. No study read for this guide compared those strengths with 10 percent or more.

What the safety tests covered

The main safety report on niacinamide was published in 2005 by the Cosmetic Ingredient Review panel, a group that assesses cosmetic ingredients. Its human test results:

• Stinging: none at strengths up to 10 percent.
• Irritation in normal use: none up to 5 percent.
• Repeated irritation over 21 days: none up to 5 percent.
• Allergy: niacinamide was not an allergen in its tests.
• Reaction to light: niacinamide did not make skin react to light.

The panel concluded that niacinamide is safe as used in cosmetics. At the time, the strengths used in products reached "a high of 3% in body and hand creams, lotions, powders and sprays." The report tested stinging up to 10 percent and irritation up to 5 percent, and no higher.

In short: 2 to 5 percent has trial results and irritation testing. Up to 10 percent has stinging testing. Above 10 percent has neither in the sources read for this guide.

Does a higher strength work better?

Some evidence says the effect grows with strength, within the tested range. A 2014 review in Skin Pharmacology and Physiology says niacinamide has several effects "depending on its concentration." A 2010 review in the Journal of Clinical and Aesthetic Dermatology reports a study with 5 percent and 2 percent niacinamide in which "the anti-aging effects of niacinamide were dose dependent." In plain words, 5 percent did more than 2 percent for those anti-aging measures.

No study read for this guide tested whether 10 or 20 percent does more than 5 percent. The same 2010 review says more research is needed "to optimize the concentration of niacinamide in cosmeceutical formulations," and a 2026 review in Skin Health and Disease says "further research is required to establish optimal concentrations, doses and treatment duration for topical niacinamide preparations."

Why a high strength can backfire

A 2026 review lists "itching, burning, mild dermatitis and greasy skin" as minor side effects of niacinamide on the skin. Dermatitis is a rash. The trials that reported few side effects used 2 to 5 percent. At higher strengths, you take on more of the ingredient without a tested gain, and people with sensitive or acne-prone skin are the most likely to notice a sting.

A high strength can also make it harder to tell what went wrong. If a 15 percent serum stings, you cannot tell whether the cause is the strength, another ingredient, or your skin that week.

How to choose your strength

Match the strength to your goal and your skin:

Your goal	Tested strength	Good starting point
Less shine and oil	2 percent	2 to 5 percent
Dry skin	2 percent in a cream	2 to 5 percent in a moisturizer
Acne, as an extra	4 to 5 percent	4 to 5 percent
Pores that look large (guide)	4 percent	2 to 5 percent
Redness and uneven tone	5 percent	2 to 5 percent
Sensitive skin	Irritation tested up to 5 percent	2 to 5 percent, fragrance free

Dark spots are a separate goal with their own studies, outside this guide.

Also check what the percentage sits in. A 5 percent moisturizer and a 5 percent serum hold the same amount of niacinamide per gram, but the amount of each product you apply can differ. The trials used whole-area, daily application of one product, so keep to one niacinamide product and leave it out of the rest of your routine.

What the percentage cannot tell you

The number on the bottle tells you how much niacinamide the product holds. It leaves out several things that affect how your skin responds:

• The rest of the formula. The trials tested specific gels, creams and moisturizers. A shop product with the same percentage has its own mix of water, oils, fragrance and other actives, and those can cause a sting or clog pores.
• The product type. A cleanser is rinsed off within a minute. A serum or cream stays on for hours. The acne, oil, redness and dry skin trials tested products that stay on the skin.
• How often you use it. Most trials applied niacinamide twice a day, every day. A strong product used now and then has no trial behind it.
• How long you use it. The trials ran 4 to 12 weeks. Any strength needs that long to judge.

So when you compare two products, the percentage is one line of the label. The non-comedogenic claim, fragrance, and the other active ingredients deserve the same attention.

Two niacinamide products at once

Many routines end up with niacinamide in two or three places: a toner, a serum and a moisturizer. The strengths do not simply add up, because each product is a separate layer, but the total amount on your skin rises. No trial read for this guide tested niacinamide from several products at once. If you want niacinamide, pick one product that holds 2 to 5 percent and leave it out of the rest, so that you stay inside the tested range and can judge the result.

When a product is not working

If you used a 2 to 5 percent product every day for 8 to 12 weeks and saw no change, a higher percentage is unlikely to be the answer, since no study shows it would help. Consider these steps instead:

1. Check the goal against the evidence. For acne, the 2024 American Academy of Dermatology guideline found too little evidence to recommend niacinamide. Adapalene 0.1 percent or benzoyl peroxide 2.5 percent has much stronger support, as the complete acne skincare routine explains.
2. For pores and oil, add the steps with more support: non-comedogenic products, gentle washing, daily sunscreen, and a retinoid at night.
3. For redness that lasts, see a doctor to rule out rosacea or eczema.

A simple start

• Choose one product with 2 to 5 percent niacinamide.
• Patch test it on the underside of the arm twice a day for 7 to 10 days, using how to patch test a new skincare product.
• Use it once a day for 2 weeks, then twice a day if your skin stays calm.
• Give it 4 weeks for oil or dryness, and 8 to 12 weeks for acne, redness or pores.
• Keep sunscreen in the morning routine.

The how to use a niacinamide serum guide covers where it goes in your routine. If you are pregnant or breastfeeding, read is niacinamide safe during pregnancy before choosing any strength, because the evidence there is limited.

When to see a doctor

Stop a niacinamide product and see a doctor if you get a rash that spreads, swelling, blisters, or burning that does not settle after you stop. See a doctor too if acne is painful, leaves marks, or has not improved after 12 weeks of steady care. No percentage of a skin care ingredient replaces treatment for those.