What is niacin?

Niacin , also known as vitamin B3 , is a vital, water-soluble vitamin from the B complex that plays a crucial role in energy metabolism , cell regeneration , and the function of the nervous system and skin .

The term "niacin" encompasses two related forms: nicotinic acid and nicotinamide (niacinamide) . Both are converted in the body to the active coenzymes NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate) . These are involved in more than 400 enzymatic reactions – making niacin one of the most versatile vitamins.

Niacin can be obtained through food or, to a limited extent, synthesized from the amino acid tryptophan . Adequate intake is therefore particularly important for people with increased energy demands, stress, intense physical activity, or an unbalanced diet.

How does niacin work in the body?

1. Energy production (cellular respiration):

Niacin is essential for the formation of NAD and NADP – two coenzymes that are present in almost all metabolic pathways.

They enable the conversion of carbohydrates, fats and proteins into ATP , the body's universal energy source.

Without niacin, energy production stalls, leading to fatigue, muscle weakness and difficulty concentrating .

2. Cell protection and DNA repair:

NAD plays a key role in repairing DNA damage and protecting cells from premature aging. It activates sirtuins , enzymes involved in cell life extension and regeneration .

Through this effect, niacin contributes to the maintenance of healthy cells and tissues and thus also has an anti-aging effect.

3. Support for the nervous system and the psyche:

Niacin is important for the production of neurotransmitters such as serotonin and dopamine. It thus supports mental clarity, concentration, and emotional stability . A deficiency can manifest as irritability, nervousness, depressive moods, or sleep problems .

4. Skin health:

Niacin contributes to cell renewal and skin regeneration . It is also frequently used in skincare products because it strengthens the skin barrier , retains moisture , and reduces inflammation .

A severe deficiency leads to rough, scaly or inflamed skin , especially in sun-exposed areas – a typical symptom of the disease pellagra .

5. Cholesterol and fat metabolism:

In higher doses, niacin can regulate cholesterol levels :

• Increases HDL cholesterol (the "good" cholesterol)
• Lowers LDL cholesterol and triglycerides
• This can help reduce the risk of arteriosclerosis and cardiovascular diseases .

6. Detoxification and liver function:

NADP plays an important role in redox reactions in the liver, where it aids in the breakdown of toxins and medications . Thus, niacin supports the body's detoxification processes .

Benefits of Niacin

• Supports energy production and metabolic activity
• Promotes healthy skin and mucous membranes
• Strengthens nerve function and mental well-being
• Protects cells from oxidative stress and DNA damage.
• Regulates cholesterol and fat metabolism
• Supports detoxification and liver health
• Contributes to normal hormone and enzyme synthesis
• Improves blood circulation and vascular function

Recommended daily intake

According to the German Nutrition Society (DGE):

• Men: 15-17 mg niacin equivalents per day
• Women: 12–14 mg niacin equivalents per day

Since the body can also produce niacin from tryptophan (1 mg niacin ≈ 60 mg tryptophan), protein-rich foods also contribute to the supply.

Natural sources of niacin

• Meat (especially poultry, beef, pork)
• Fish (tuna, salmon, mackerel)
• whole grain products
• Legumes (lentils, peas, soybeans)
• Nuts and seeds
• Mushrooms
• potatoes
• Coffee

Deficiency symptoms

Niacin deficiency can occur due to an unbalanced diet , chronic alcohol abuse , nutrient absorption disorders , or tryptophan deficiency .

Early symptoms:

• Fatigue, loss of appetite
• Irritability, depressive mood
• Skin redness, inflammation
• Digestive problems

Severe deficiency (pellagra):

The classic triad of symptoms is:

• Dermatitis – inflamed, scaly skin
• Diarrhea – Indigestion, diarrhea
• Dementia – mental confusion and cognitive impairment

Without treatment, pellagra can be fatal – however, the disease is extremely rare in developed countries.

Overdose and safety

With a normal diet, an overdose is practically impossible.

However, high-dose supplements (>100 mg/day) can trigger a so-called niacin flush in the short term:

• Sensation of warmth, skin reddening, itching
• A slight tingling sensation in the face or arms
• This reaction is harmless and disappears after a few minutes.

However, very high doses over a longer period (from 1 g/day) can strain the liver and should only be taken under medical supervision.

Conclusion

Niacin (vitamin B3) is a versatile vitamin that supports the body in almost all energy and metabolic processes. It ensures efficient energy production , strengthens nerves, skin and mental well-being , and protects cells from oxidative stress.

Thanks to its effects on blood lipids, circulation, and regeneration, niacin is of great importance for general health as well as for athletes and active people . A balanced diet including meat, fish, whole grains, and legumes usually ensures an adequate supply.

Sources

1. German Nutrition Society (DGE). (2020): Reference values ​​for nutrient intake – Niacin.
2. Jacobson TA. (2008): A “hot” topic in dyslipidemia management — “Niacin” and flushing. N Engl J Med , 358(20), 2187–2194.
3. Kirkland JB. (2014): Niacin status, NAD distribution and ADP-ribose metabolism. Curr Pharm Des , 15(1), 3–11.
4. Trammell SAJ, Brenner C. (2013): Targeting nicotinamide adenine dinucleotide metabolism in metabolic and neurodegenerative disorders. Nat Rev Drug Discov , 12(7), 533–550.