GlyNAC (glycine + NAC)

GlyNAC · glycine NAC · glycine and N-acetylcysteine

A glycine + N-acetylcysteine combination studied to restore glutathione and mitochondrial function with age.

TypeSupplement / dietary

The grade answers: What does the human evidence support for: Glutathione & mitochondrial support?

Grade

Limited

The grade rates evidence quality — it is not advice to take or buy.

Class: Antioxidant / precursor
Primary use: Glutathione & mitochondrial support
Evidence strength: low
Last reviewed: 2026-07-01

Bottom line

Intriguing early trials from a single research group show broad improvements in older adults — but the studies are small and largely unreplicated. Promising, not yet proven.

What the evidence says

GlyNAC pairs the two rate-limiting building blocks of glutathione. A series of small trials (predominantly from one group) reports improvements in glutathione levels, oxidative stress, mitochondrial function, insulin sensitivity, strength and even some aging biomarkers in older adults. That breadth is exciting — and exactly why independent replication matters before drawing firm conclusions. The trials are small, some open-label, and concentrated in one lab. Grade C reflects real promise held back by limited, not-yet-replicated evidence.

Key studies

[1]
GlyNAC supplementation in older adults (trials) · RCT / pilot
Broad marker improvements — small samples, mostly one group.
Open on PubMed ↗
[2]
GlyNAC and oxidative stress / aging hallmarks · review
Mechanistic case across several aging hallmarks.
Open on PubMed ↗
[3]
Glutathione decline with age (review) · review
Rationale for restoring glutathione in older adults.
Open on PubMed ↗

See all studies on PubMed ↗

Mechanism

Supplies glycine and cysteine (via NAC) to raise cellular glutathione, aiming to lower oxidative stress and restore mitochondrial function that declines with age.

Safety

Both components are well tolerated individually; the combination has been safe in the trials reported so far, over months rather than years.

Dosage context

Studied at weight-based doses of both amino acids under trial conditions. There is no standardised over-the-counter GlyNAC dose, and products vary widely.

Examples of application

Used as the glycine + NAC pair studied in older adults.
Dosing follows trial protocols; over-the-counter products vary.
Promising but not independently replicated — treat as experimental.

From the field

GlyNAC produces the most impressive-sounding results of any supplement here — and the thinnest independent replication. We hold it at C until other labs reproduce it, however good the story sounds.

Related molecules

GlycineC N-Acetylcysteine (NAC)C

How we assign grades → Method