Glutathione vs NAD+
Glutathione (Endogenous antioxidant tripeptide) and NAD+ (Cellular coenzyme (dinucleotide)) are documented as co-studied in the PeptiDex library. This page puts the two entries side by side on class, molecular weight, half-life, origin, mechanism and studied research areas — every value taken from the entry it belongs to.
Why these two are co-studied
Cross-referenced for research context — not a usage or combination recommendation.
At a glance
| Attribute | Glutathione | NAD+ |
|---|---|---|
| Compound class | Endogenous antioxidant tripeptide | Cellular coenzyme (dinucleotide) |
| Research category | Healing & Recovery | Longevity & Cellular |
| Length (amino acids) | 3 amino acids | Not documented |
| Molecular weight | 307.32 g/mol | 663.43 g/mol (free acid) |
| Half-life | ~15 minutes (plasma, after IV) | Not documented |
| Origin | Glutathione is a naturally occurring tripeptide synthesized in virtually all human cells from glutamate, cysteine and glycine. It is one of the body's principal intracellular antioxidants and is not a synthetic research peptide. | Nicotinamide adenine dinucleotide (NAD+) is a naturally occurring coenzyme present in all living cells, first described in the early 20th century in the context of fermentation and cellular respiration. It is not a peptide but a dinucleotide composed of a nicotinamide moiety and an adenine moiety joined through ribose and phosphate groups. |
“Not documented” means the PeptiDex entry records no value for that field. Nothing on this page is estimated, and no figure is carried over from one compound to the other.
How Glutathione works
Glutathione acts as a major intracellular antioxidant and redox buffer, neutralizing reactive oxygen species and participating in the glutathione peroxidase and glutathione-S-transferase systems. It supports detoxification of certain xenobiotics and helps maintain the redox state of protein thiols. It cycles between reduced (GSH) and oxidized (GSSG) forms as part of cellular redox homeostasis.
How NAD+ works
NAD+ functions as a central redox cofactor, cycling between its oxidized (NAD+) and reduced (NADH) forms to shuttle electrons in glycolysis, the citric acid cycle, and oxidative phosphorylation. Beyond redox chemistry, NAD+ is a required substrate for enzymes that consume it, including sirtuins (NAD+-dependent deacylases), poly(ADP-ribose) polymerases (PARPs) involved in DNA repair, and CD38. Cellular NAD+ levels have been reported to decline with age in various tissues, which is a focus of aging research. It is synthesized de novo from tryptophan and through salvage pathways from precursors such as nicotinamide, nicotinic acid, and nicotinamide riboside.
Mechanistic descriptions reflect published research-literature understanding and are quoted from each compound's own entry. Much peptide research is preclinical (in-vitro or animal-model); mechanism in humans may differ and is not established for many compounds.
Where each one appears in the literature
The research contexts each entry documents. Listing a research area is not a claim of efficacy or a therapeutic indication, and the two lists are not scored against each other.
Glutathione
NAD+
What sets each apart
Glutathione
Unlike the synthetic research peptides in this group, glutathione is an endogenous, well-studied antioxidant tripeptide available as a supplement rather than a research-only compound.
NAD+
Unlike the peptides in this category, NAD+ is a small-molecule coenzyme central to redox metabolism rather than a signaling peptide, and it is studied primarily via precursor supplementation.
Frequently asked questions
What is glutathione?
Glutathione (GSH) is a tripeptide, L-gamma-glutamyl-L-cysteinyl-glycine, found in virtually all cells and functioning as a major intracellular antioxidant. It is notable for an unusual gamma peptide bond between the glutamate side chain and cysteine, and for the reactive thiol on its cysteine residue that carries out its redox chemistry. It is an endogenous molecule rather than a synthetic research peptide.
What is glutathione studied for?
It is researched for its roles in antioxidant defense, detoxification, and redox homeostasis, neutralizing reactive oxygen species, free radicals, peroxides, and heavy metals. In applied research it is examined in the context of oxidative-stress conditions and, popularly, skin-related outcomes. As a supplement or IV agent its systemic efficacy remains debated.
Why does the gamma peptide bond in glutathione matter?
The gamma linkage between glutamate and cysteine is not the standard alpha peptide bond, which makes glutathione resistant to cleavage by ordinary peptidases and contributes to its intracellular stability. Only the enzyme gamma-glutamyl transpeptidase can break this bond, which is central to how glutathione is recycled and transported.
What is NAD+ and what is it studied for?
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme central to cellular energy metabolism, redox reactions, and as a substrate for sirtuins and PARP enzymes involved in DNA repair. It is studied in models of aging, mitochondrial function, metabolic decline, and neuroprotection, where tissue NAD+ levels fall with age. It is a naturally occurring coenzyme, not a peptide.
Is NAD+ a peptide?
No. NAD+ is a dinucleotide coenzyme composed of two nucleotides (one bearing adenine, the other nicotinamide) joined through phosphate groups, not a chain of amino acids. It is grouped in longevity research catalogs alongside peptides because of its role in aging and mitochondrial studies, but it is a distinct chemical class.
How does NAD+ differ from precursors like NMN and NR?
NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside) are biosynthetic precursors that cells convert into NAD+, whereas NAD+ is the finished coenzyme. Precursors are commonly studied as oral routes to raise intracellular NAD+, while NAD+ itself is studied via IV or subcutaneous routes in research settings. Direct cellular uptake of intact NAD+ is a subject of ongoing research.
Answers are the ones published on each compound's own PeptiDex entry. They are educational summaries of research-literature context and are not medical advice.