Niacinamide, also known as the amide of vitamin B3

Vitamin B3 is made up of niacin (nicotinic acid) and its amide, niacinamide. For more information on vitamins abcde.

Niacinamide content in food
Niacinamide is found in many foods, including yeast, meat, fish, milk, eggs, green vegetables, and cereal grains.

Niacinamide made from tryptophan
Nicotinamide, also known as niacinamide and nicotinic acid amide, is the amide of nicotinic acid (vitamin B3). Dietary tryptophan is able to convert to niacin in the body.

Vitamin B complex
Niacinamide is often found in combination with other B vitamins including thiamine, riboflavin, pantothenic acid, pyridoxine, cyanocobalamin, and folic acid.

Niacinamide and arthritis
Q. Niacinamide is one supplement i'm particularly interesting in. A friend of mine recently told me that it was effective in treating his arthritis, which i remember was quite a problem for him in years past. I haven't yet found anything conclusively supportive or damning in regards to the use of niacinamide for arthritis. The main support of it's use in this direction is a study done by a Dr. William Kaufman which I've been unable to obtain so far. Though there are many articles on niacinamide, i haven't been able to find the studies themselves.
   A. We found on clinical study regarding the role of niacinamide and arthritis.

The effect of niacinamide on osteoarthritis: a pilot study.
Inflamm Res. 1996 July. Jonas WB, Rapoza CP, Blair WF. Office of Alternative Medicine, National Institute of Health, Bethesda, MD 20892, USA.
Seventy two patients with osteoarthritis were randomized for treatment with niacinamide or an identical placebo for 12 weeks. Global arthritis impact improved in subjects on niacinamide and worsened by 10% in placebo subjects. Pain levels did not change but those on niacinamide reduced their anti-inflammatory medications by 13%. Niacinamide reduced erythrocyte sedimentation rate by 22% and increased joint mobility by 4.5 degrees over controls. Side effects were mild but higher in the niacinamide group. This study indicates that niacinamide may have a role in the treatment of osteoarthritis. Niacinamide improved the global impact of osteoarthritis, improved joint flexibility, reduced inflammation, and allowed for reduction in standard anti-inflammatory medications when compared to placebo. More extensive evaluation of niacinamide in arthritis is warranted.