Niacinamide generally works well with most products, but it's best not to combine it with vitamin C (ascorbic acid) in the same routine as it can cause irritation. Additionally, avoid using it with strong exfoliants or retinoids in high concentrations to prevent skin sensitivity. For more, check out my Quora Profile.
Mixing Guide: In its truest form, Niacinamide is readily water-soluble and dissolves in water-based products, such as serums and creams, with ease. The Ordinary's 100% Niacinamide Powder can be mixed into any non-conflicting, water-based treatment, provided that the pH of the base is between 5.0 and 7.0.
Treatment of Niacin Deficiency
Nicotinamide is usually used to treat niacin deficiency because nicotinamide, unlike nicotinic acid (the most common form of niacin), does not cause flushing, itching, burning, or tingling sensations. Nicotinamide is given in doses of 250 to 500 mg orally daily.
Niacin Deficiency Causes
Today, most people in the developed world get plenty of niacin in their diets. Niacin deficiency is more likely to be caused by problems that affect the absorption of niacin or tryptophan. The most common cause is alcoholism.
Along with aspirin, indomethacin (33), ibuprofen (69) and naproxen (32) have been shown in subjects to decrease the flushing effects of IR niacin. The most common dose of aspirin used to effectively reduce flushing in IR niacin is 325 mg, with 650 mg offering no further benefit (70).
[15] Isoniazid decreases niacin levels by inhibiting its intestinal absorption and endogenous production from tryptophan.
That means your skin, the mucous lining of your gastrointestinal tract, and your brain. Classic pellagra shows up as a collection of symptoms that healthcare providers describe as the “3 Ds”: diarrhea, dermatitis, and dementia. Some add a fourth “D” to include death.
While animal products like fish, poultry, and meat have high amounts of niacin, you can obtain it from fruits like avocados and bananas, and other plant sources like mushrooms, whole grains, peanuts, potatoes, etc.
Niacinamide and vitamin C
This combination sparks a lot of debate among skincare experts. Some say that since both niacinamide and vitamin C contain antioxidants, they cancel each other out and might even lead to irritation.
Although the names sound similar, niacin and niacinamide are not the same. Niacinamide is a form of niacin that is made when you have an excess of niacin in your body. As a supplement, niacinamide is often found in products that protect and nourish the skin or treat acne.
Niacinamide-containing foods or supplements are safe when taken in doses lower than 35 mg daily. Niacinamide is possibly safe when taken in doses up to 900-1500 mg daily. It might cause side effects such as stomach upset, gas, dizziness, headache, and rash.
Niacin in the form of nicotinamide has fewer side effects than nicotinic acid. However, at high doses of 500 mg/day or more, nicotinamide can cause diarrhea and easy bruising and can increase bleeding from wounds. Even higher doses of 3,000 mg/day or more can cause nausea, vomiting, and liver damage.
Niacinamide works well with other skincare ingredients, including retinol and hyaluronic acid. However, some ingredients, like vitamin C, may interact negatively with niacinamide. Therefore, it's recommended to use products containing these ingredients at different times of the day or on alternate days.
When researchers looked into this connecting, they identified the molecular pathway for skin flushing that is caused by vitamin B3 (niacin).
The supplement has been linked with liver damage, can cause hypotension and might activate a peptic ulcer. Taking niacin also might worsen allergies, gallbladder disease and symptoms of certain thyroid disorders. If you have diabetes, niacin can interfere with blood glucose control.
14 Niacin is a potent releaser of histamine from mast cells15 and also has been shown to stimulate the secretion of the dermally- derived vasodilator, prostaglandin D2 (PGD2). 16,17 Niacin might stimulate the gas- tric mast cells to release histamine (1).
Niacinamide has been shown to ease inflammation, which can help calm redness due to conditions like acne, rosacea and eczema. It can also soothe irritation caused by strong exfoliants like retinol or glycolic acid that remove dead cells from the surface of your skin.
Avoid drinking alcohol or hot drinks or eating spicy foods around the time you take Niaspan®. This helps decrease flushing of your face. If you stop taking this medicine for any period of time, contact your doctor prior to restarting taking niacin.
In short: Niacin is used for support for healthy cholesterol levels already within the normal range. Niacinamide is used for support for joint comfort, support for sugar balance and support for brain function, but does not support cholesterol balance.
But you're unlikely to consume enough niacin from food sources to cause a flush. For example, a serving of canned tuna contains about 8 mg of niacin, and a serving of peanuts contains around 4 mg. But, if you take supplements or consume energy drinks, you may be getting higher niacin doses without realizing it.