What is Niacin Produced From? A Deep Dive into Natural and Synthetic Sources

January 13, 2026 •

4 min read

Over 60% of commercially produced niacin is used for animal feed, but its origins for human consumption are both natural and synthetic. Niacin, or vitamin B3, is a water-soluble vitamin essential for metabolism and cell function. Understanding what is niacin produced from reveals its diverse pathways, from dietary intake to industrial synthesis.

Quick Summary

Niacin is produced naturally in the human body from the amino acid tryptophan or acquired directly from various foods. Industrially, it is synthesized via chemical processes involving 3-methylpyridine or other precursors. Many fortified foods also provide a readily available source of this essential B vitamin.

Key Points

Endogenous Production: Niacin can be synthesized in the human body from the essential amino acid tryptophan via the kynurenine pathway, though this process is not very efficient.
Bioavailability: Niacin from animal sources (like meat and fish) is highly bioavailable, while niacin in some grains like corn is bound and less available unless treated.
Industrial Raw Materials: Commercially, niacin is primarily synthesized from pyridine derivatives such as 3-methylpyridine through chemical oxidation processes.
Modern Manufacturing: More environmentally friendly enzymatic synthesis using specific bacteria is a growing method for industrial niacin production.
Fortification: Many common food products, like breads and cereals, are enriched and fortified with synthetically produced niacin to ensure adequate dietary intake.
Essential Co-factors: The body's ability to convert tryptophan to niacin relies on the presence of other nutrients, including riboflavin, vitamin B6, and iron.
Forms of Niacin: The term niacin encompasses multiple forms, including nicotinic acid and nicotinamide, which are produced through both natural and synthetic means.

Niacin Production: A Two-Fold Approach

Niacin, also known as vitamin B3, is vital for numerous bodily functions, including energy metabolism and DNA repair. It exists in multiple forms, including nicotinic acid and nicotinamide, and its origin depends on whether it's sourced naturally or synthesized industrially for fortification and supplements.

Natural Biosynthesis in the Body

For humans, one of the primary methods for niacin production is the conversion of the amino acid tryptophan. This process occurs mainly in the liver through a multi-step metabolic route known as the kynurenine pathway.

The Kynurenine Pathway: This is the body's natural synthesis route for niacin. It starts with tryptophan and involves a series of enzymatic reactions that ultimately produce nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+), the active coenzyme forms of niacin.
Efficiency and Co-factors: This conversion is not highly efficient, requiring approximately 60mg of tryptophan to produce just 1mg of niacin. Several other nutrients, including riboflavin (B2), vitamin B6, and iron, act as essential co-factors for the enzymes in this pathway.
Impact of Diet: The efficiency of this conversion highlights why relying on dietary tryptophan alone is unreliable. Diets low in protein or those relying heavily on corn (where niacin is poorly bioavailable) can lead to niacin deficiency, or pellagra.

Dietary Sources of Preformed Niacin

Besides the internal conversion, the most straightforward way to obtain niacin is through dietary intake of foods already containing the vitamin. Niacin from food is readily absorbed and processed by the body.

Animal-Based Foods: Meat, poultry, and fish are excellent and highly bioavailable sources of niacin, where it exists in the active forms of NAD and NADP. Examples include beef liver, chicken breast, tuna, and salmon.
Plant-Based Foods: While often containing less niacin per serving, plant sources are also important. These include peanuts, legumes, whole grains, avocados, and mushrooms. Some grains, like corn, have niacin in a bound form (niacytin) that is poorly absorbed unless treated with an alkali, a process known as nixtamalization.
Enriched and Fortified Foods: Many breads, cereals, and flours are fortified with niacin during processing. The niacin added to these products is in its free form and is therefore highly bioavailable to the body.

Industrial and Commercial Synthesis

For manufacturing fortified foods, animal feed, and supplements, niacin is synthetically produced on a massive scale.

Chemical Synthesis from Picolines: A dominant method involves the oxidation of pyridine derivatives like 3-methylpyridine (3-picoline) or 5-ethyl-2-methylpyridine. The reaction often uses strong oxidants like nitric acid or air with a catalyst, converting the starting material into nicotinic acid or nicotinamide. Newer, "greener" methods are also being developed using technologies like enzymatic hydrolysis to reduce the production of harmful by-products.
Biocatalyst-Mediated Synthesis: A more sustainable method involves using microorganisms, such as Rhodococcus rhodochrous, to catalyze the hydrolysis of 3-cyanopyridine into niacin. This enzymatic approach operates under milder conditions than chemical methods, produces fewer toxic by-products, and offers a high conversion rate.

Comparison of Niacin Production Methods


Feature	Natural Conversion (from Tryptophan)	Dietary Intake (Preformed Niacin)	Industrial Synthesis
Primary Source	Tryptophan (essential amino acid)	Protein-rich foods, whole grains, fortified cereals	Chemical precursors (e.g., 3-methylpyridine)
Efficiency	Relatively inefficient (60:1 ratio)	Highly efficient and direct absorption	Highly efficient, engineered for maximum yield
Dependence on Co-factors	Requires riboflavin, B6, and iron	Less dependent on other nutrients for uptake	None for production; final product purity is key
Bioavailability	Varies depending on diet and co-factor availability	Depends on the food source (e.g., better in meat than corn)	Excellent for fortification due to free-form vitamin
Scale of Production	Internal, individual human metabolism	Part of standard food consumption	Large-scale, commercial production for food and supplements

Conclusion

Niacin, a critical B vitamin, originates from both natural and synthetic pathways. The human body can produce it endogenously from the amino acid tryptophan, though this process is inefficient and requires co-factors like B6 and iron. A more reliable source for dietary needs comes from preformed niacin found in a wide variety of animal- and plant-based foods, as well as enriched and fortified products. For the large-scale production required by the food and supplement industries, chemical synthesis, historically relying on the oxidation of pyridine compounds, has been the norm. However, modern advancements are favoring more sustainable enzymatic methods to reduce environmental impact and improve efficiency, ensuring a consistent and high-quality supply of this essential vitamin.

Visit the Office of Dietary Supplements, NIH for more information on Niacin.

Keypoints

Dual Origin: Niacin is either produced naturally in the body from the amino acid tryptophan or obtained directly from dietary intake.
Internal Conversion: The body synthesizes niacin from tryptophan through a multi-step metabolic process that is not very efficient, requiring a significant amount of tryptophan for a small niacin yield.
Dietary Sources: Food sources like meat, poultry, fish, peanuts, and fortified cereals provide readily available niacin.
Industrial Synthesis: Commercial niacin is manufactured synthetically from chemical precursors like 3-methylpyridine for use in food fortification, supplements, and animal feed.
Enzymatic Production: Modern industrial processes are increasingly moving towards more sustainable, enzymatic synthesis methods using microorganisms to produce niacin.

Frequently Asked Questions

The primary natural sources of niacin are both dietary and internal. You can get preformed niacin from a variety of animal and plant-based foods, or your body can synthesize it from the amino acid tryptophan.

Yes, the human body can produce niacin in the liver from the essential amino acid tryptophan. However, this process is not very efficient, and requires other nutrients like vitamin B6, riboflavin, and iron to function properly.

For supplements and fortified foods, niacin is typically produced synthetically through industrial processes. A common method involves the oxidation of pyridine derivatives, such as 3-methylpyridine, using catalysts.

The niacin naturally present in corn is largely in a bound form called niacytin, which is not easily absorbed by the human digestive system. The traditional process of treating corn with an alkaline solution, known as nixtamalization, makes this niacin bioavailable.

The kynurenine pathway is the metabolic route used by the body to convert the amino acid tryptophan into niacin and its active coenzyme forms, NAD+ and NADP+. It is the main route for endogenous niacin synthesis.

Yes, modern advancements include more sustainable enzymatic synthesis methods. This approach uses microorganisms to catalyze the hydrolysis of 3-cyanopyridine into niacin, often resulting in higher yields and fewer toxic by-products compared to traditional chemical synthesis.

If there are insufficient levels of co-factors like riboflavin, vitamin B6, or iron, the body's conversion of tryptophan to niacin is hindered. This can contribute to niacin deficiency, even if dietary intake of protein is adequate.

Niacinamide is a specific form of niacin (nicotinic acid amide). While the body can convert excess niacin to niacinamide, both can be produced synthetically. For example, industrial methods often produce 3-cyanopyridine which is then hydrolyzed to either nicotinamide (niacinamide) or nicotinic acid.