NAD+ Precursor
NAD+ precursors are molecules that can be converted into NAD+, a vital coenzyme found in all living cells, crucial for energy production, cellular repair, and longevity. Taking NAD+ directly is generally considered inefficient due to its inability to enter cells directly due to its large size and polar nature, making it unable to cross the cell membrane effectively. Thus, NAD+ precursors like NMN, NR, and NA, which are smaller and can enter cells more easily, are used to increase cellular NAD+ levels, as they can be converted into NAD+ once inside the cells. These precursors are therefore preferred for supplementation to boost NAD+ levels efficiently within the body.
- Nicotinamide Mononucleotide (NMN): A prominent NAD+ precursor, NMN, is involved in the biosynthesis of NAD+. NMN enters cells via specific transporters and is converted to NAD+ through a series of enzymatic reactions.
- Nicotinamide Riboside (NR): Another significant precursor, NR, is converted into NMN before participating in NAD+ synthesis. NR can enter cells through unique transporters and is phosphorylated to NMN by the enzyme NR kinase.
- Nicotinamide (NAM): NAM, a form of vitamin B3, is also a precursor of NAD+, contributing to its synthesis through the salvage pathway. NAM is converted to NMN by the enzyme nicotinamide phosphoribosyltransferase (NAMPT).
- Nicotinic Acid (NA): NA, another form of vitamin B3, serves as a precursor of NAD+ through the Preiss-Handler pathway. NA is converted to NAD+ via a series of enzymatic reactions, first to nicotinic acid mononucleotide (NAMN), then to nicotinic acid adenine dinucleotide (NAAD), and finally to NAD+.