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Longevity & Skin
A core cellular coenzyme that declines with age — popular for 'energy', thin on proof.
Longevity & Skin
The body's main antioxidant — popular for skin lightening, with thin evidence for it.
NAD+ is not FDA-approved and rated 2/5 for evidence; Glutathione is not FDA-approved and rated 3/5. Glutathione has more human evidence behind it. Both are used for longevity & skin goals.
| Compare | NAD+ A core cellular coenzyme that declines with age — popular for 'energy', thin on proof. | Glutathione The body's main antioxidant — popular for skin lightening, with thin evidence for it. |
|---|---|---|
| Category | Longevity & Skin | Longevity & Skin |
| Evidence | 2/5Strong biology and mouse aging studies; human trials mostly test oral precursors (NR, NMN). Direct NAD+ injection/infusion has only small pharmacokinetic studies. | 3/5A handful of small human trials (mostly oral, a few IV) with modest, inconsistent skin-lightening results. Well-studied as a natural molecule, but not as a cosmetic drug. |
| FDA status | Not FDA-approved as a drug | Not FDA-approved; oral forms sold as supplements |
| WADA (sport) | Not on the Prohibited List | Not on the Prohibited List |
| Also known as | Nicotinamide adenine dinucleotide, β-NAD, Coenzyme I | GSH, Reduced glutathione, L-Glutathione, γ-Glutamyl-cysteinyl-glycine |
| How it works | Shuttles electrons in energy metabolism and is consumed by sirtuins, PARPs (DNA repair) and CD38. Injected NAD+ is likely broken down to smaller precursors outside cells before being taken up, so how much reaches cells intact is unclear. | Its cysteine thiol (-SH) group neutralizes reactive oxygen species and recycles other antioxidants. For skin, it is thought to shift melanin production from dark eumelanin toward lighter pheomelanin and to inhibit tyrosinase, the enzyme that starts melanin synthesis. How much of an injected dose reaches skin cells is unclear — it is broken down quickly in blood. |
| Half-life | Short in blood (minutes to hours); quickly broken down to precursors | Very short in blood after IV (minutes); levels return to baseline quickly |
| Commonly reported doses |
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| Route | Subcutaneous | Intramuscular or subcutaneous |
| Good once mixed | ~14 days in the fridge | ~14 days in the fridge |
| Top side effects |
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| Lowest research-listing price per mg | $0.08 (500 mg vial, 40% off) | $0.02 (1500 mg vial, 40% off) |
| Latest lab purity | 99.18% (lot NAD0002) | 99.41% (lot GLT0003) |
Want a third? Add another peptide. Doses are commonly reported ranges, not recommendations.
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NAD+ is not FDA-approved and rated 2/5 for evidence; Glutathione is not FDA-approved and rated 3/5. Glutathione has more human evidence behind it. Both are used for longevity & skin goals.
NAD+: Not FDA-approved as a drug. Glutathione: Not FDA-approved; oral forms sold as supplements. Regulations change, so confirm with the FDA.
NAD+ is rated 2 out of 5: Strong biology and mouse aging studies; human trials mostly test oral precursors (NR, NMN). Direct NAD+ injection/infusion has only small pharmacokinetic studies. Glutathione is rated 3 out of 5: A handful of small human trials (mostly oral, a few IV) with modest, inconsistent skin-lightening results. Well-studied as a natural molecule, but not as a cosmetic drug. The scale is explained on our methodology page.
NAD+ is not named on the WADA list, though the general rule on non-approved substances (S0) can still apply. Glutathione is not named on the WADA list, though the general rule on non-approved substances (S0) can still apply.