The Truth About Niacinamide | What Concentration Really Works for Pores, Dark Spots, and Wrinkles? Part 5 of the 'Choosing Truly Necessary Serums Based on Medical Research' Series

At the pharmacy, I picked up a 10% niacinamide serum.

The packaging lists words that seem to address almost every concern: "pores," "translucency," "firmness," "sebum," and "rough skin."

However, a question remains.

Can a single ingredient really be effective for pores, dark spots, and wrinkles alike?

Furthermore, there are products with different concentrations: 5%, 10%, and 20%. While it feels like a higher number means higher effectiveness, medically, it is not that simple.

In this article, we will clarify what can be expected from niacinamide and where the marketing hype begins, based on the latest research and clinical studies.

To give you the conclusion first, niacinamide is an ingredient that may gently improve skin tone unevenness and fine lines while supporting the skin's barrier function.

On the other hand, it is not an ingredient that physically closes pores or erases deep wrinkles or dark spots.

Also, for general anti-aging care, there are clinical studies even at around 2–5%. There is currently insufficient evidence to claim that it is ineffective unless it is 10% or higher.

What is Niacinamide?

Niacinamide is a form of vitamin B3, also known as nicotinamide.

Although the name contains "nicotine," it is a different substance from nicotine, the addictive component in tobacco.

In the body, it serves as a precursor to the coenzymes NAD and NADP, which are involved in cellular energy production and repair reactions. In the skin, its role in suppressing oxidative stress and inflammatory responses, as well as supporting skin barrier function and cellular metabolism, has been studied [1].

A 2024 review organized the multiple mechanisms of action for niacinamide related to skin oxidative stress, inflammation, pigmentation, cellular aging, and the skin barrier. However, actions confirmed in basic research do not necessarily guarantee the visible effects of over-the-counter serums [1].

Is it effective for dark spots and dullness?

Niacinamide is not an ingredient that directly destroys the cells that produce melanin.

It is thought to primarily inhibit the process by which melanin produced by melanocytes is transferred to surrounding epidermal cells.

Long-standing clinical trials have reported that topical niacinamide at around 2–5% gently improves facial pigmentation and uneven skin tone [2].

In 2025, a study was reported comparing a serum combining 5% niacinamide with tranexamic acid, a vitamin C derivative, and hydroxy acids against 4% hydroquinone. Both groups showed improvement in melasma pigmentation, and the combination serum was superior in terms of moisturizing properties and usage feel [3].

However, this result cannot be interpreted as "5% niacinamide is equivalent to hydroquinone."

This is because this serum also contains tranexamic acid, vitamin C derivatives, and acidic ingredients, making it impossible to isolate the effects of niacinamide alone.

Therefore, while it is an option for daily dullness or mild skin tone unevenness, it is not appropriate to attempt to treat melasma or distinct pigmented spots with a serum alone.

How effective is it for wrinkles?

Niacinamide has the potential to suppress oxidative damage and inflammation in the skin, protecting extracellular matrices such as collagen [1].

A 2023 review on skin aging summarized that topical application of niacinamide has been reported to improve skin texture, fine lines, pigmented spots, and redness. On the other hand, its action is milder than topical tretinoin, and it is not an ingredient expected to provide the same level of wrinkle improvement [4].

In other words, niacinamide is useful as gentle, low-irritation anti-aging care, but it does not necessarily serve as a substitute for retinol or medical-grade retinoids.

It is also difficult to erase deeply etched wrinkles or wrinkles caused by facial muscle movement with a serum alone.

Do pores really get smaller?

'Pore improvement' is a common claim seen with niacinamide serums.

Niacinamide has the potential to regulate sebum secretion and improve skin roughness and hydration levels. As a result, it is conceivable that shadows and irregularities in pores may become less noticeable [4].

However, pores have multiple causes, including sebum, keratin plugs, acne, hair thickness, and loss of elasticity due to aging.

It has not been proven that niacinamide shrinks pores themselves and closes them permanently.

While it may improve the appearance for those whose pores are noticeable due to high sebum and skin surface roughness, sufficient effects cannot be expected for irregularities caused by sagging or acne scars.

Actually, its most certain strength is 'barrier function'

When considering the value of niacinamide, one cannot overlook its effect on the skin barrier.

It is known to support the production of lipids and ceramides in the stratum corneum and potentially suppress transepidermal water loss.

A 2025 study examined the effects of niacinamide on the moisture retention and molecular structure of the stratum corneum using methods such as X-ray diffraction. While this was not a clinical trial evaluating wrinkles on human faces, it is research that supports the mechanism by which niacinamide enters the stratum corneum and influences hydration status [5].

For dry and easily irritated skin, improving the barrier condition can sometimes improve appearance more effectively than directly targeting wrinkles or pores.

It is easier to understand the characteristics of niacinamide if you think of it not as an 'aggressive serum,' but as an ingredient that protects while gradually conditioning the skin.

2%, 5%, 10%—which one is best after all?

The concentrations most commonly used in clinical studies are primarily around 2–5% [2,4].

At around 5%, effects on uneven skin tone, fine lines, and skin texture have been investigated.

On the other hand, high-concentration products such as 10%, 15%, and 20% are increasing among commercial items. However, there is a lack of high-quality comparative studies proving that effectiveness increases proportionally with higher concentrations.

Increasing the concentration can, for some people, cause

redness

itching

stinging

dryness

.

For first-time users or those with sensitive skin, it is reasonable to start with around 2–5%. If your toner or emulsion already contains niacinamide, there is no need to layer multiple products.

Who Niacinamide Is For

Niacinamide is suitable for the following people:

Those who easily experience irritation from retinol or acidic vitamin C

Those who want to address dryness and mild uneven skin tone at the same time

Those concerned about sebum or skin roughness

Those who want to consolidate complex skincare into one product

It can be used morning or night and can also be used in combination with vitamin C or retinol.

However, if you start multiple beauty ingredients at once, you will not be able to determine the cause if skin irritation occurs. It is safer to introduce new ingredients one by one and observe the reaction over several weeks.

The True Evaluation of Niacinamide

Niacinamide is not a 'miracle ingredient' that produces dramatic changes.

However,

it is relatively non-irritating,

it supports the skin barrier function,

and it has the potential to gently improve skin tone unevenness and fine lines,

making it a very easy-to-use ingredient.

And what is important is that it does not mean it is meaningless unless it is 10% or higher.

Start with a concentration of around 2–5%, using it as a base alongside moisturizers and sunscreen, and continue without overdoing it.

What brings out the true potential of niacinamide is not the high-concentration number, but a formulation that can be used consistently without causing irritation.

Next time (Part 6), we will examine ingredients that are even more difficult to judge.

Do peptide serums really work? To what extent is the term 'topical collagen' medically accurate? Click here for Part 6 ☟.

References

[1] Marques C, Hadjab F, Slama M, et al. Mechanistic insights into the multiple functions of niacinamide: Therapeutic implications and cosmeceutical applications in functional skincare products. Antioxidants. 2024;13(4):425. doi:10.3390/antiox13040425.

[2] Bissett DL, Miyamoto K, Sun P, Li J, Berge CA. Topical niacinamide reduces yellowing, wrinkling, red blotchiness, and hyperpigmented spots in aging facial skin. International Journal of Cosmetic Science. 2004;26(5):231-238. doi:10.1111/j.1467-2494.2004.00228.x.

[3] Rocio J, et al. Evaluation of the efficacy of a serum containing niacinamide, tranexamic acid, vitamin C, and hydroxy acid compared to 4% hydroquinone in the management of melasma. Journal of Cosmetic Dermatology. 2025;24(3):e70097. doi:10.1111/jocd.70097.

[4] Griffiths TW, Watson REB, Langton AK. Skin ageing and topical rejuvenation strategies. British Journal of Dermatology. 2023;189(Suppl 1):i17-i23. doi:10.1093/bjd/ljad282.

[5] Sjöberg T, Fsahaye A, Nilsson EJ, et al. Niacinamide and its impact on stratum corneum hydration and structure. Scientific Reports. 2025;15:4953. doi:10.1038/s41598-025-88899-0.