Our cosmetic and personal care products are full of ingredients we don’t know much about. We must, therefore, check every list of ingredients in order to take full control of our skin and prevent unwanted adverse effects. Using a certain product only because of the hype surrounding it does not mean that the ingredients in it would work for you!
In this article, we will look into one popular ingredient: Niacinamide. This component is basically a form of vitamin B3, which can either make your skin beautiful and healthy, or rarely, cause irritation or acne breakouts. The effect depends on your particular skin type and your sensitivity to niacinamide.
Below we discuss both the positive and negative effects of topical vitamin B3 that you can expect when you first apply it on your skin.
Let’s dive in!
How can niacinamide benefit your skin?
Vitamin B3 is an essential nutrient that stimulates the proper functioning, development, and replenishment of skin cells. It plays a vital part in the natural exfoliation process in the epidermis (the top skin layer) when new skin cells are produced to replace dead or damaged ones. 
As a result, the topical application of products with niacinamide is associated with various skin benefits:
Younger looking skin
According to a study published in the International Journal of Cosmetic Science, topical application of vitamin B3 may have a positive effect on mature skin because of its potential to fade signs of aging.  The study results suggested that niacinamide can improve symptoms like wrinkles, fine lines, hyper or hypopigmentation, uneven texture, red spots, and yellowing, sallow looking skin.
Stronger skin barrier
When applied externally, niacinamide can strengthen the protective skin barrier by boosting the cell turnover in the epidermis.  As the epidermis is the most superficial layer of the skin, it has direct contact with external damaging factors, also called free radicals. This may include UV light, pollution, oxidative stress, extreme temperatures, cosmetic chemicals, etc. But how does vitamin B3 help?
Well, niacinamide can stimulate the synthesis of ceramides and facilitate the bonding process between lipids in the epidermis. This way, the niacinamide may strengthen the skin barrier and thicken the epidermis layer to reduce the risk of external damage caused by allergens, bacteria, and other free radicals. This process might result in the improved capacity of the skin to retain moisture and hydration for a longer period of time, making niacinamide a preferred choice for people with skin prone to dryness and dehydration.
Reduced acne symptoms
Acne vulgaris (also called inflammatory acne) is one of the most trickly skin conditions because of its complex nature: the skin is inflamed, and at the same time, dry with hyper-functioning sebaceous glands and sensitive pores. Fortunately, evidence suggests that topical products containing 2-4% niacinamide together with oral supplements of vitamin B3 (niacinamide), zinc, copper, and folic acid can be used to reduce inflammation and improve the symptoms of acne vulgaris. 
The symptoms of comedonal acne (also known as non-inflammatory acne) include milia, blackheads, pimples, redness, and other skin imperfections.  Studies suggest that topical products containing niacinamide can be used effectively in the treatment of this type of acne.  Besides, because of its antimicrobial properties, this cosmetic ingredient is associated with reduced risk of inflammation and improved overall skin condition in individuals with oily and acne-prone skin.
What are the side effects of vitamin B3?
Even though dermatology studies consider topical niacinamide at 2%-4% to be a safe cosmetic ingredient, and unlikely to cause an allergic reaction, there are individuals who can experience sensitivity. 
Any topical skincare product used by an individual with sensitive skin can cause a worsening of their present skin condition. See list below:
- Clogged pores
Those symptoms are reported by random people on Reddit and are not backed by a scientific source.
Whenever there is a strong concern that an individual could be allergic to, or irritated by the active or inactive ingredients in a topical product, formal patch testing is appropriate . A board certified dermatologist or allergist can perform this test very easily for you in their office.
Of note, scientific evidence shows that both oral niacin and oral niacinamide in some individuals can intensify already present allergic reactions by increasing histamine production in the body. 
If there is a minor concern that a topical niacinamide preparation could be irritating, you can always do a quick patch test yourself:
Apply a small amount of the product (with Vitamin B3 content) on the skin of the inner arm or neck and cover with a nonstick pad overnight. In the morning if the skin is pink, red, itchy, or feels irritated, do not use the product on your face. If you apply the product on the back of your hand, for example, (where the skin is more dull), you risk getting inaccurate patch test results. So play it safe, because your face is not for experiments!