Vitamin B3—also known as niacin—is one of the most versatile B vitamins. It is involved in over 400 enzymatic reactions, plays a central role in energy metabolism, and supports the skin, nervous system, and mental health. Even the body’s own DNA repair mechanisms require niacin.

In this article, you will learn why the body cannot function without niacin, which symptoms indicate a deficiency—and how the vitamin can be used therapeutically, for example, in cases of high cholesterol or skin conditions.

What Is Vitamin B3 and What Are Its Functions?¹ ²

Vitamin B3, also known as niacin, is a collective term for two related compounds: nicotinic acid and nicotinamide (sometimes also called niacinamide). Both forms have vital roles in energy metabolism: the body uses them to form the coenzymes NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate), which are tiny “power plants” present in virtually every cell (Bogan et al., 2008).

However, nicotinic acid and nicotinamide differ in their effects: while nicotinic acid is known for its vasodilatory and cholesterol-lowering effects, nicotinamide is primarily used in dietary supplements and dermatology due to its good tolerability.

Key Functions of Vitamin B3 at a Glance

The compounds grouped under this umbrella term perform the following functions:

·       Central role in energy metabolism (ATP production in mitochondria)

·       Cellular protection and DNA repair

·       Support of skin and nerve regeneration

·       Detoxification via the liver

·       Inhibition of inflammatory processes

·       Mental health

Vitamin B3 – Daily Requirements and Good Sources³

The recommended intake of niacin according to the NIH (National Institutes of Health, USA):

·       Women: approx. 14 mg/day

·       Men: approx. 16 mg/day

·       Pregnant/breastfeeding women: 17/18 mg/day

1 mg niacin = 60 mg tryptophan (from which the body can also form niacin).

Die Medical Uses of Vitamin B3

Niacin is used in high doses in medicine, particularly for:

·       Glaucoma: Nicotinamide can improve retinal function (Hui et al., 2020).

·       Skin disorders and care: Nicotinamide is used for acne and skin cancer, among other things, and to protect the skin barrier in cosmetics (Ong et al., 2024).

·       Migraine: Smaller studies and case reports suggest a positive effect of high-dose niacin on migraines (e.g. Liu et al., 2022).

·       Peripheral arterial occlusive disease (PAOD) of the lower extremities: Niacin can help slow the progression of atherosclerosis by lowering LDL and triglycerides while increasing HDL. Large studies have examined its combination with statins – with mixed results (McDermott et al., 2024).

Stay Young and Fit with Vitamin B3 – Research on NAD⁺ and Longevity

As mentioned above, niacin also acts as a key precursor to the coenzyme NAD⁺ (nicotinamide adenine dinucleotide)—a central substance in cellular metabolism. NAD⁺ is essential for hundreds of enzymatic processes such as cellular respiration, DNA repair, and the function of sirtuins—enzymes that regulate aging and cell protection (Lautrup et al., 2024).

As we age, NAD⁺ levels in the body decline significantly—a change associated with muscle weakness, inflammation, mitochondrial dysfunction, and neurodegenerative diseases (Lautrup et al., 2024).

It is therefore not surprising that a vitamin B3 deficiency can manifest as concentration problems.

Symptoms of Vitamin B3 Deficiency⁴

A severe deficiency leads to pellagra (Italian for “rough skin”), classically marked by the “3 Ds”:

·       Dermatitis (symmetrical rash, especially in sun-exposed areas)

·       Dementia-like symptoms (confusion, memory problems)

·       Diarrhea (persistent diarrhea)

Further (less severe symptoms) include:

·       Loss of appetite

·       Fatigue

·       Depression

·       Inflamed mucous membranes

·       Burning tongue

What Are Risk Factors for Deficiency?⁵

The following factors can promote a vitamin B3 deficiency:

·       Excessive alcohol consumption

·       Unbalanced diet

·       Liver cirrhosis

·       Chronic intestinal diseases (e.g. ulcerative colitis)

·       Long-term treatment with isoniazid, levodopa, or certain chemotherapeutics

·       Persistent vitamin B6 deficiency

·       Vegan diet lacking tryptophan-rich or fortified foods

Good Sources of Vitamin B3⁶

Niacin is found in both animal and plant-based foods. Especially good sources include:

•         Chicken breast, cooked: 13.7 mg/100 g

•         Tuna, frifrie.                 10.1 mg/100 g

•         Beef liver, cooked:        13.2 mg/100 g

•         Peanuts, roasted:           13.8 mg/100 g
•      Mushrooms, raw:            3.6 mg/100 g
  

•         Brown rice, cooked:        2.6 mg/100 g

•      It is important to note that niacin is more bioavailable from animal sources than from plant sources.

Notes on Taking B3 Supplements⁷

Niacin supplements should ideally be taken with meals. This improves stomach tolerance.

FAQ – Frequently Asked Questions About Vitamin B3

1. Can the body produce vitamin B3 on its own?

Partially. The body can form it from the amino acid tryptophan—but only in small amounts and only if enough other micronutrients (especially B1, B2, B6, and iron) are available. About 60 mg of tryptophan are needed to produce 1 mg of niacin—so the body’s own production is usually not sufficient to meet daily needs.

2. Can the body store vitamin B3?

Only to a limited extent, since vitamin B3 is water-soluble and stored only in small amounts—e.g. in the liver. These reserves typically last only a few weeks, which is why a regular intake through diet or supplements is necessary.

3. Can you overdose on nicotinic acid?

Yes, especially when taking high doses of nicotinic acid (>500 mg/day over a longer period), it can strain the liver, particularly with sustained-release forms.

Flush symptoms (redness, heat sensation) can occur at much lower doses (starting around 30 mg). In such cases, it may be possible to switch to nicotinamide and consult medical professionals.

4. Can vitamin B3 interact with medications?

Yes, especially at high doses. Potential interactions can occur with:

o   Blood pressure medications: additional blood pressure lowering

o   Antidiabetics: possible increase in blood sugar levels

o   Anticoagulants: increased risk of bleeding

If you take medication regularly, always consult healthcare professionals before using B3 supplements. That said, nicotinamide is a well-tolerated form with few interactions and side effects.

Conclusion: Vitamin B3 – Energy and Cellular Protection

B3 is more than just a metabolism vitamin. It combines energy production with skin regeneration, vascular protection, and mental stability—especially under stress, with skin issues, or inflammation. Best—and easiest—to take in combination with other B vitamins (→ blog post Vitamin B Complex).

For more information, feel free to read our other blog articles—also on B vitamins—and visit our online shop. There you will also find the volumes of our Codex Humanus and the series Medizinskandale, where B vitamins are also discussed.

Sources:

·       ¹

https://ods.od.nih.gov/factsheets/Niacin-HealthProfessional/

·       ²

https://health.clevelandclinic.org/b-vitamin-benefits

·       ⁴World Health Organisation: “Pellagra and its prevention and control in major emergencies”, 23. Februar 2000.

·       Bogan, K. L. et al. (2008): “Nicotinic acid, nicotinamide, and nicotinamide riboside: a molecular evaluation of NAD+ precursor vitamins in human nutrition”, Annu. Rev. Nutr.

·       Liu, H. et al. (2022): “Association between Dietary Niacin Intake and Migraine among American Adults: National Health and Nutrition Examination Survey”, Nutrients.

·       Ong, R. R. et al. (2024): “Niacinamide: a review on dermal delivery strategies”, Drug Deliv Transl Res.

·       McDermott, M. M. et al. (2024): “Nicotinamide riboside for peripheral artery disease: the NICE randomized clinical trial”, Nat. Commun.

·       Lautrup, S. et al. (2024): “Roles of NAD⁺ in Health and Aging”, Cold Spring Harb Perspect Med.