Niacinamide vs niacin: pills, flushing and skin

Niacinamide, nicotinamide, niacin and nicotinic acid all appear on skin care labels, supplement bottles and in medical papers. The names overlap, and so do the uses, which makes it easy to mix them up. This guide sorts out which names mean the same thing, why one form causes flushing, and what the pill trials found for skin cancer and acne. For what niacinamide does on the skin, start with what niacinamide does for your skin.

The names, sorted

Name	What it is	Where you see it
Niacinamide	A form of vitamin B3	Skin care labels
Nicotinamide	The same substance as niacinamide	Supplement labels, medical papers, pill trials
Niacin	The other form of vitamin B3; also a general name for vitamin B3	Food labels, supplements, cholesterol medicine
Nicotinic acid	The same substance as niacin	Medical papers
Vitamin B3	The name that covers both forms	Nutrition advice

A 2004 review in the Journal of Cosmetic Dermatology explains the link: niacin and niacinamide "are similarly effective as a vitamin because they can be converted into each other within the organism. The blanket term vitamin B(3) is used for both." A 2014 review in the same journal adds that "nicotinic acid, also known as niacin, is converted into nicotinamide in the body."

MedlinePlus, from the U.S. National Library of Medicine, describes niacin as "a type of B vitamin. It is a water-soluble vitamin. It is not stored in the body." Water-soluble means it dissolves in water.

As a vitamin, they count the same

For nutrition, both forms count toward your daily need. MedlinePlus lists 14 milligrams a day for females aged 14 and older, 16 milligrams for males, 18 milligrams during pregnancy and 17 milligrams during breastfeeding. Most people get this from food.

As medicines, they behave differently

The difference shows up at high doses.

Niacin causes flushing. MedlinePlus says that "when given as a treatment for people with high cholesterol, niacin supplements can cause flushing, which is a feeling of warmth, redness, itching or tingling of the face, neck, arms or upper chest." It also lists the effects of too much niacin: high blood sugar, liver damage, stomach ulcers and skin rashes.

Niacinamide does not. A 2010 review in the Journal of Clinical and Aesthetic Dermatology states: "In contrast to nicotinic acid, niacinamide does not cause skin flushing nor does it cause changes in blood pressure, pulse, or body temperature." The review adds that because niacinamide has fewer side effects, it has been studied more as a skin care ingredient.

That difference in side effects is the reason the 2010 review gives for skin care research focusing on niacinamide.

Niacinamide pills and skin cancer

Niacinamide pills, usually called nicotinamide in the trials, have their strongest evidence for one specific use: lowering new skin cancers in people at high risk.

Trial	People	Dose	Result
ONTRAC, 2015, New England Journal of Medicine	386 adults with at least two non-melanoma skin cancers in the past 5 years	500 milligrams twice a day for 12 months	23 percent fewer new non-melanoma skin cancers than placebo, meaning look-alike pills with no active ingredient; no benefit after stopping
ONTRANS, 2023, New England Journal of Medicine	158 organ transplant recipients with at least two past skin cancers	500 milligrams twice a day for 12 months	No reduction in new skin cancers; stopped early because too few people joined

Non-melanoma skin cancers are the common skin cancers, such as basal cell and squamous cell carcinoma. In the ONTRAC trial, side effects were similar in both groups during the year of treatment.

The American Academy of Dermatology describes nicotinamide as "a supplement prescribed to reduce the risk of developing skin cancer," and says "studies have found that people who have a high risk of developing skin cancer can reduce their risk by taking nicotinamide." For organ transplant recipients, it says "there is limited data." It also says that people who take a medicine or supplement to prevent skin cancer still need shade, sun-protective clothing and sunscreen.

A 2022 review of 29 trials with 3,039 patients found nicotinamide pills were linked to fewer skin cancers, and also to more "digestive AEs," meaning stomach and gut side effects.

These trials were in adults at high risk of skin cancer. They tell us nothing about healthy young people with acne, and taking the pills is a decision to make with a doctor.

Niacinamide pills and acne

The evidence for pills against acne is weaker:

• A 2017 review in Dermatologic Therapy found two studies of an oral supplement containing nicotinamide. Both showed fewer pimples than at the start. The review still called the effect of oral and topical nicotinamide on acne "unclear."
• The 2024 American Academy of Dermatology acne guideline found the evidence insufficient to recommend "oral or topical niacinamide for acne treatment."
• The NHS says a pharmacist can recommend acne treatments including "supplements that come as tablets, such as zinc, niacinamide and vitamin A."

So a niacinamide tablet is an option some pharmacists offer, with little evidence behind it for acne. The treatments with strong evidence are in the complete acne skincare routine, and a doctor can prescribe more. Those treatments need 8 to 12 weeks, as how long an acne routine takes to work explains.

Safety of the pills

At 500 milligrams twice a day, the ONTRAC trial found no noteworthy difference in side effects between nicotinamide and placebo over a year. The 2022 review of 29 trials found more stomach and gut side effects. A 2014 review in the Journal of Cosmetic Dermatology discusses "suggestions nicotinamide might have a role in the development of diabetes, Parkinson's disease, and liver damage" with excessive exposure. The review calls these suggestions, and they concern large doses by mouth.

Ask a doctor or pharmacist before taking any vitamin B3 pill, and more so if you:

• have liver disease, diabetes or stomach ulcers,
• take other medicines,
• are pregnant or breastfeeding (see is niacinamide safe during pregnancy),
• have rosacea, since the American Academy of Dermatology says vitamin B3 can trigger a rosacea flare.

Creams and pills are different tools

A 2 to 5 percent niacinamide cream and a 500 milligram pill share a name, and the research treats them as separate tools:

	Niacinamide on the skin	Niacinamide pills
Tested strengths	2 to 5 percent	500 milligrams twice a day
Studied for	Oil, acne, redness, dryness, pores	Skin cancer prevention in high-risk adults; acne in a few small studies
Main side effects	Itching, burning, mild rash, greasy feel, all uncommon	Stomach and gut problems
Flushing	None reported	None reported for niacinamide; flushing is a niacin effect
Who decides	You, with a patch test	A doctor

No trial read for this guide showed that a cream prevents skin cancer. Sunscreen, shade and clothing remain the protection for everyone. The niacinamide side effects guide covers reactions to skin products in more detail.

Common mix-ups

The overlapping names lead to a few mistakes that are easy to avoid:

• Buying niacin when you meant niacinamide. A bottle labeled "niacin" or "nicotinic acid" is the form that can cause flushing. If a doctor suggested nicotinamide, check the label says nicotinamide or niacinamide.
• Doubling up. A multivitamin, a B-complex pill and a separate niacinamide pill can all contain vitamin B3. Add up the milligrams on each label and show the list to a pharmacist.
• Expecting a serum to act like a pill. No trial read for this guide tested skin care at 2 to 5 percent for skin cancer prevention, and the pill trials tested pills only.
• Taking pills for acne before trying proven treatments. The 2024 AAD guideline found too little evidence for oral niacinamide in acne, while adapalene and benzoyl peroxide have strong support.

How to read the labels

On a skin care product, niacinamide appears in the ingredient list, and the front may give a percentage. On a pill bottle, check the name of the form, niacin, nicotinic acid, nicotinamide or niacinamide, and the amount in milligrams per tablet. The two products use different units, a percentage on skin care and milligrams on pills, which is one more sign that they are separate tools.

If a doctor has prescribed nicotinamide for skin cancer prevention, follow the dose they gave you, keep every follow-up skin check, and keep up sunscreen, shade and clothing. The AAD says those protections are still needed with any skin cancer medicine or supplement.

When to see a doctor

See a doctor before starting vitamin B3 pills for any reason, and at once for flushing with chest pain, trouble breathing or fainting after any pill. See a dermatologist if you have had skin cancer before, since they can advise whether nicotinamide pills suit you, and for any skin spot that is new, changing, bleeding or not healing.