Head to head
NAC against GlyNAC
NAC alone against NAC with glycine added, on the argument that glutathione synthesis needs both. GlyNAC's human work is in older adults and reports improvements across many markers at once, which is a pattern worth reading carefully rather than a stronger result.
Column A
NACN-Acetylcysteine
A glutathione precursor that is FDA-approved as a mucolytic and antidote for acetaminophen overdose, and studied more broadly in psychiatry and respiratory health.
Column B
GlyNACGlyNAC (Glycine + N-Acetylcysteine)
A combination of glycine and NAC studied in older adults for restoring glutathione and improving multiple markers of aging.
Side by side, on the facts we can check
| Attribute | NAC | GlyNAC |
|---|---|---|
| Category | Antioxidant | Antioxidant |
| FDA status | FDA-approved (mucolytic; acetaminophen overdose antidote); also sold as a supplement | Supplement combination; not an approved drug |
| Half-life | ~5-6 hours | Short (both components) |
| Molecular weight | 163.2 Da | Mixture; glycine 75.1 Da plus N-acetylcysteine 163.2 Da |
| Mechanism | Provides cysteine to replenish glutathione, directly scavenges free radicals, and modulates glutamatergic signaling in the brain. | Supplies glycine and cysteine to rebuild depleted glutathione, lowering oxidative stress and supporting mitochondrial function. |
| Human studies cited | 3 | 2 |
| Legal status, US | FDA-approved drug and sold as a supplement | Sold as a dietary supplement |
Frequently asked questions
What is the difference between NAC and GlyNAC?
NAC: A glutathione precursor that is FDA-approved as a mucolytic and antidote for acetaminophen overdose, and studied more broadly in psychiatry and respiratory health. GlyNAC: A combination of glycine and NAC studied in older adults for restoring glutathione and improving multiple markers of aging.
Which has stronger research evidence, NAC or GlyNAC?
This database does not grade compounds. It counts what was run in people: 3 of the 4 studies cited on the NAC profile were human work, against 2 of 2 for GlyNAC. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are NAC and GlyNAC FDA-approved?
NAC: FDA-approved (mucolytic; acetaminophen overdose antidote); also sold as a supplement. GlyNAC: Supplement combination; not an approved drug.
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.