Nicotinuric acid

Nicotinuric acid is the glycine conjugate of nicotinic acid, an excretory metabolite marking niacin intake and the detoxification arm of vitamin B3 metabolism that feeds NAD⁺ biosynthesis. Salivary nicotinuric acid reflects niacin status and turnover relevant to the NAD⁺-dependent energy metabolism underpinning exercise capacity. Ringseis et al. (2020) linked nicotinic acid availability to muscle oxidative adaptation and endurance performance.