Peptide Comparison
NAD+ vs Glutathione
Editorial breakdown of mechanism, evidence, decision criteria, and the misconceptions worth calling out.
Depends on goal
Both are endogenous molecules sold as intravenous infusions at wellness clinics, and both have plasma half-lives measured in minutes, which is the central problem with infusing either. Glutathione is the one with a randomized double-blind trial: a 2009 evaluation in Parkinson's disease found it well tolerated with no safety concerns and no statistically significant benefit. NAD+ infusion has tolerability data and observational reports, with a 2026 real-world comparison concluding that metabolic outcomes were variable and further study is needed. Neither has established that raising the plasma level raises the intracellular level where the molecule does its work. Consult a qualified clinician before any human use.
Evidence at a glance
FDA-approved Phase 3 Phase 2 / approved abroad Anecdotal + animal Preclinical / flagged
The actual difference
NAD+ is a redox coenzyme and the substrate that sirtuins and PARPs consume. Glutathione is a tripeptide antioxidant that reduces reactive oxygen species and conjugates toxins for phase II excretion. Reported NAD+ infusions run 250 to 1000 mg over several hours; glutathione runs 600 to 2400 mg one to three times weekly. Oral glutathione has poor bioavailability, which is the reason the intravenous route dominates its clinical literature.
Which one to pick
Pick NAD+ if
- The endpoint concerns sirtuin or PARP biology, where NAD+ is the substrate
- Precursor research is the actual interest, since nicotinamide riboside and nicotinamide mononucleotide carry more oral human data than NAD+ itself
- Infusion tolerability rather than efficacy is the question
Pick Glutathione if
- A randomized double-blind human trial is required, since glutathione has one and NAD+ infusion does not
- The endpoint concerns oxidative stress or phase II conjugation
- Nebulized or oral routes are relevant, both of which glutathione has been studied in
Avoid both if
- The case for infusion rests on clinic marketing rather than published endpoints
- There is a history of infusion hypersensitivity
- Cost is a constraint, since neither has demonstrated a clinical outcome in a controlled trial
Common confusions
- 'NAD+ IV reverses aging'. No controlled trial supports that. The strongest published statement, from a 2026 real-world comparison of NAD+ and nicotinamide riboside infusions, is preliminary tolerability and short-term safety, with exploratory metabolic outcomes described as variable.
- 'Glutathione IV is proven'. Overstated. The best-known randomized double-blind evaluation, in Parkinson's disease in 2009, found it well tolerated and reported no significant benefit, with the authors describing a possible mild symptomatic effect that would need a larger study to establish.
- 'A short plasma half-life does not matter because the molecule gets into cells'. That is the assumption under both infusions and it is the part that has not been demonstrated. Neither compound has shown that an infusion raises intracellular concentration at a target tissue.
Side-by-side
| NAD+ | Glutathione | |
|---|---|---|
| Class | Coenzyme (non-peptide); longevity supplement | Endogenous tripeptide antioxidant |
| Drug class | Longevity | Longevity |
| Mechanism | Substrate for sirtuins and PARPs; essential for redox reactions and DNA repair | Reduces reactive oxygen species; conjugates toxins for excretion (phase II detox) |
| Route | IV / SC | IV / Oral / Nebulized |
| Half-life | Minutes (IV plasma) | ~5-15 min (plasma) |
| Dosage (research) | 100-500 mg SC daily; 250-1000 mg IV over hours | 600-2400 mg IV 1-3x weekly; 500-1000 mg oral liposomal daily |
| Evidence tier | Observational + Anecdotal | Observational + Some RCTs |
| Research depth | 274 indexed | 274 indexed |
| Availability | Supplement / IV Clinic | Supplement / IV Clinic |
| Reported risks | Flushing; nausea; chest tightness with IV infusion; cost | Questionable oral bioavailability; rare IV hypersensitivity |
Reported research data only. "Studied for" and "reported in literature" describe published research focus, not clinical recommendation. Most peptides catalogued here are not FDA-approved for human use.
Frequently asked questions
Should I pick NAD+ or Glutathione?
Both are endogenous molecules sold as intravenous infusions at wellness clinics, and both have plasma half-lives measured in minutes, which is the central problem with infusing either. Glutathione is the one with a randomized double-blind trial: a 2009 evaluation in Parkinson's disease found it well tolerated with no safety concerns and no statistically significant benefit. NAD+ infusion has tolerability data and observational reports, with a 2026 real-world comparison concluding that metabolic outcomes were variable and further study is needed. Neither has established that raising the plasma level raises the intracellular level where the molecule does its work. Consult a qualified clinician before any human use.
What is the difference between NAD+ and Glutathione?
NAD+ is classed as Coenzyme (non-peptide); longevity supplement; Glutathione is classed as Endogenous tripeptide antioxidant. Reported mechanism: NAD+, Substrate for sirtuins and PARPs; essential for redox reactions and DNA repair; Glutathione, Reduces reactive oxygen species; conjugates toxins for excretion (phase II detox). Reported half-life: NAD+, Minutes (IV plasma); Glutathione, ~5-15 min (plasma). Routes in published studies: NAD+, IV / SC; Glutathione, IV / Oral / Nebulized.
Which has stronger evidence, NAD+ or Glutathione?
NAD+ and Glutathione sit on the same rung of PeptideHelper.org's five-step evidence scale, which runs from preclinical to FDA-approved. NAD+ is graded Observational + Anecdotal, with 31 cited sources on its reference page and 274 indexed studies. Glutathione is graded Observational + Some RCTs, with 54 cited sources on its reference page and 274 indexed studies.
Which is more accessible, NAD+ or Glutathione?
Neither NAD+ nor Glutathione is an FDA-approved drug. Catalog status: NAD+, Supplement / IV Clinic; Glutathione, Supplement / IV Clinic.
Are NAD+ and Glutathione ever combined?
NAD+ and Glutathione appear together in no stack catalogued on PeptideHelper.org, and the interaction engine raises no flag for the pair.
Open the PeptideHelper.org compare tool to add more compounds to this side-by-side and filter by evidence tier interactively.
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