NAD+ vs Glutathione
Two injectables sold alongside peptides that are not really peptides. What does each one do?
Reviewed by the amino101 editorial team. , first published .
Neither NAD+ nor glutathione is a peptide in the usual sense, and both get sold in the same lyophilized vials by the same vendors. Glutathione is technically a tripeptide of glutamate, cysteine and glycine, though with an unusual bond that protects it from most peptidases. NAD+ is not a peptide at all; it is a coenzyme made of two nucleotides, found in every cell, that shuttles electrons in energy metabolism and feeds enzymes involved in DNA repair. They are compared because clinics infuse them together and because both are marketed for energy, aging and recovery. The evidence for each is uneven. NAD+ has strong mouse data for precursors like NR and NMN but only a small pharmacokinetic study of direct infusion in humans. Glutathione has human trials for chemotherapy nerve protection and a six month oral trial that raised body stores, plus weaker data for Parkinson's and skin lightening. Neither is approved as a drug in the US. This is an educational comparison of two compounds with modest human evidence.
| NAD+ | Glutathione | |
|---|---|---|
| Typical dosage | 50 to 100 mg per injection | 200 to 600 mg (injectable); 250 to 1000 mg daily (oral) |
| Frequency | daily or a few times per week for injections; IV infusions weekly to monthly | 2 to 3 times weekly (injectable); daily (oral) |
| Route | Subcutaneous, Intramuscular, Intravenous, Oral | Intravenous, Intramuscular, Subcutaneous, Oral, Intranasal |
| Half-life | minutes in plasma; rapidly broken down to nicotinamide and other metabolites | approximately 10 to 15 minutes in plasma; intracellular turnover measured in hours to days |
| Cycle | ongoing or blocks of several weeks | ongoing, or 8 to 12 week courses |
| Research level | Well researched | Extensively studied |
| Human trials | Small pilots | Approved drug |
| Status | Unapproved as a drug; sold as a compounded injectable, IV infusion, and supplement | Dietary supplement (oral) and compounded injectable in the US. Approved injectable drug in some countries for chemotherapy support. |
| Effects timeline | flush or fatigue 20 to 60 minutes after injection, energy later that day for some; anything cumulative takes 2 to 4 weeks and is subjective | energy and recovery 1 to 2 weeks, skin tone changes 4 to 12 weeks, measured blood glutathione rise 1 to 6 months on oral |
Key differences
NAD+ vs Glutathione dosage
Dosage patterns reported in research and community protocols, by goal. Taken from each compound page. Not a prescription.
| Goal | Dosage | Frequency |
|---|---|---|
| Daily subcutaneous | 50 mg | once daily |
| Higher subcutaneous | 100 mg | once daily or every other day |
| Intramuscular | 50 to 100 mg | 2 to 3 times weekly |
| Clinic infusion | 250 to 1000 mg | weekly to monthly |
| Oral precursor alternative | 250 to 1000 mg NR or NMN | once daily |
| Goal | Dosage | Frequency |
|---|---|---|
| General antioxidant support, injectable | 200 to 600 mg | 2 to 3 times weekly |
| IV clinic infusion | 600 mg to 2 g | weekly or as scheduled |
| Daily oral | 250 to 1000 mg | once daily |
| Skin tone | 500 to 1000 mg | once daily |
| Supporting natural production | 600 to 1200 mg NAC plus glycine | daily |
Convert any of these to syringe units in the dosage calculator.
Side effects compared
- ▲Stinging, redness, or swelling at the injection site
- ▲Flush, chest tightness, cramping, and nausea, mainly with fast IV infusion
- ▲Transient fatigue or a flu-like feeling after injection
- ▲Headache
- ▲Possible depletion of methyl groups at large doses, a debated concern
- ▲Sulfur smell or taste after injection
- ▲Nausea or stomach cramps, more with oral doses
- ▲Injection site pain or bruising
- ▲Skin rash or flushing
- ▲Bronchospasm in rare cases, mostly in people with asthma or sulfite sensitivity
Which should you choose?
NAD+ is the fit for someone interested in mitochondrial energy metabolism and aging biology who understands that the human data is thin and the benefit is subjective. Reported injection doses are 50 to 100 mg, subcutaneous or intramuscular, in the morning because of the flush and fatigue wave. Oral NR or NMN at 250 to 1000 mg daily is a cheaper route with actual RCT data for raising blood NAD+.
Glutathione is the fit for antioxidant and liver support with actual human trial history, including an approved use for chemotherapy nerve protection in some countries. Injectable protocols report 200 to 600 mg two to three times weekly. For most people, oral NAC and glycine to support natural production is the better understood and cheaper option. Avoid unregulated IV lightening clinics.
Glutathione has the better human evidence and the clearer mechanism, so if you are picking one for general antioxidant support, it is the more defensible choice, and the cheapest way to raise it is oral N-acetylcysteine rather than injections. NAD+ has the more exciting biology and the weaker direct data: the mouse work mostly used precursors, injected NAD+ probably does not enter cells intact, and the one human infusion study showed it being broken down rather than absorbed. Neither has a trial showing it does what the clinics promise for fatigue or aging. People run them together because the pathways overlap, NAD+ supports the enzyme that recycles oxidized glutathione, and that pairing is described in the NAD+ and glutathione stack. The practical risks are different: NAD+ injections sting and fast infusions cause chest tightness; glutathione oxidizes quickly in solution and high dose IV lightening treatments from unregulated clinics have produced kidney and liver problems. Expect subjective results at best.
Stacking: Commonly paired, often in the same clinic infusion. NAD+ supplies the cofactor for recycling oxidized glutathione, which is the mechanistic argument; there is no combined trial.
NAD+ is a coenzyme found in every living cell, not a peptide. It is central to energy metabolism and DNA repair, declines with age, and is injected or infused by people hoping to restore energy, cognition, and cellular resilience.
Glutathione is a tripeptide of glutamate, cysteine and glycine that every cell makes as its main antioxidant. People use it by injection, IV, oral, liposomal or nebulized routes for oxidative stress, liver support, immune health and skin lightening.
NAD+ vs Glutathione: frequently asked
Is NAD+ a peptide?
No. It is a coenzyme made of two nucleotides joined by their phosphate groups. It appears in peptide databases and vendor catalogs because it is sold as a lyophilized powder and injected the same way. Glutathione is a tripeptide, so it technically qualifies, though it is usually grouped with supplements rather than research peptides.
Can you take NAD+ and glutathione together?
Yes, and clinics often infuse them in the same session. NAD+ supports glutathione reductase, the enzyme that recycles oxidized glutathione, so there is a mechanistic argument for the pair. No trial has tested the combination; see the NAD+ and glutathione stack.
Which is better for energy, NAD+ or glutathione?
NAD+ is the one marketed for energy and it is central to energy metabolism, but human evidence that injecting it improves fatigue is lacking; the one infusion study showed rapid breakdown. Glutathione is an antioxidant, not an energy molecule. Honest answer: neither has a trial showing improved energy in healthy adults.
Does injected NAD+ actually work?
Unclear. NAD+ is not transported intact into most cells; it is likely broken down outside cells into nicotinamide and nicotinamide riboside, which cells rebuild. So an injection probably works, if it works, as a precursor delivery. Oral NR and NMN do the same thing with better data.
What are the side effects of NAD+ injections versus glutathione?
NAD+ injections sting and can cause a flush, a temporary flu-like feeling, or fatigue; fast IV infusions cause chest tightness, cramping and nausea. Glutathione injections produce a sulfur smell, occasional nausea, and rarely bronchospasm in people with asthma or sulfite sensitivity. Neither has serious reported toxicity at community doses.
Related reading
Sources
- A pilot study investigating changes in the human plasma and urine NAD+ metabolome during a 6 hour intravenous infusion of NAD+. Frontiers in Aging Neuroscience, 2019
- Randomized controlled trial of oral glutathione supplementation on body stores of glutathione. European Journal of Nutrition, 2015