GlyNAC: the most promising longevity stack from Baylor
Guide to GlyNAC (glycine + N-acetylcysteine). The Baylor study that reversed aging markers in humans. Mechanism, dosing and best brands.
In 2021, a team at Baylor College of Medicine published a study that made waves in the longevity community. It wasn't an exotic compound or a patented molecule. It was two cheap amino acids anyone can buy: glycine and N-acetylcysteine (NAC). The combination, called GlyNAC, reversed multiple aging markers in older adults in just 16 weeks.
The Baylor study
Kumar et al., 2023 (The Journals of Gerontology): Randomized, double-blind, placebo-controlled trial in 36 older adults (mean age 72). 16 weeks of GlyNAC (glycine 1.33 mmol/kg/day + NAC 0.81 mmol/kg/day) vs placebo.
Results:
- Intracellular glutathione: restored to young adult levels (+54%)
- Oxidative stress: significant reduction (F2-isoprostanes -28%)
- Mitochondrial dysfunction: improved (citrate synthase +30%)
- Inflammation: IL-6 significantly reduced
- Insulin resistance: HOMA-IR improved
- Endothelial damage: reduced
- Muscle strength: improved (grip strength +12%)
- Gait speed: increased
- Waist circumference: reduced (-3 cm)
- Cognition: improvement in processing speed and working memory
The effects reversed 12 weeks after stopping GlyNAC. This suggests continuous supplementation is necessary.
Why it matters
It is one of the few human studies demonstrating simultaneous reversal of multiple hallmarks of aging with a simple intervention. Most longevity supplements improve 1-2 markers. GlyNAC improved 8+.
“GlyNAC corrects the glutathione deficiency that occurs with aging, and in doing so, improves multiple age-associated defects. It is not a generic anti-aging supplement. It is a correction of a measurable biochemical deficit.”
Mechanism: glutathione as the cornerstone
What is glutathione
Glutathione (GSH) is the most abundant antioxidant inside cells. It is synthesized from three amino acids: glycine, cysteine and glutamate. With age, glutathione synthesis declines because glycine and cysteine levels drop (not glutamate).
Why GlyNAC and not direct glutathione
Oral glutathione is degraded in the digestive tract. It doesn't reach cells intact. GlyNAC provides the two rate-limiting precursors (glycine + cysteine via NAC) so cells synthesize their own glutathione. It is more efficient than taking glutathione directly.
Cascade of effects
- GlyNAC restores intracellular glutathione
- Glutathione normalizes mitochondrial function
- Healthy mitochondria reduce oxidative stress
- Lower oxidative stress reduces inflammation
- Lower inflammation improves insulin sensitivity
- All of the above improves muscle, cognitive and metabolic function
Dosing
Baylor study protocol
- Glycine: 100 mg/kg/day (7g for a 70 kg person)
- NAC: 100 mg/kg/day (7g for a 70 kg person)
- Split into 2 doses (morning and evening)
- Duration: 16 weeks minimum
Simplified practical protocol
- Glycine: 3-5g, twice daily (6-10g total)
- NAC: 600-900mg, twice daily (1200-1800mg total)
- Timing: with or without food (both absorb well)
- Form: glycine powder (dissolves in water, slightly sweet), NAC in capsules
NOW Foods Glycine Powder 1lb
Pure glycine powder from NOW Foods. Slightly sweet taste, dissolves easily in water. 454g lasts 2-3 months on the GlyNAC protocol.
NOW Foods NAC 600mg
N-Acetyl Cysteine from NOW Foods. Cysteine precursor for glutathione synthesis. 250 capsules of 600mg.
Monthly cost
| Component | Daily dose | Product | Cost/month |
|---|---|---|---|
| Glycine | 6-10g | NOW Foods Powder 454g | $4-6 |
| NAC | 1200-1800mg | NOW Foods NAC 600mg 250ct | $3-5 |
| Total | $7-11/month |
It is one of the cheapest longevity stacks that exist. For context: a month of NMN costs $40-70.
Safety
- Glycine: extremely safe. It is a non-essential amino acid the body produces naturally. Doses up to 15g/day used in studies without adverse effects
- NAC: safe at doses up to 2400mg/day. Used clinically as an antidote for acetaminophen overdose. May cause mild digestive discomfort initially
- NAC contraindication: patients on chemotherapy (consult oncologist). Antioxidants may interfere with oxidative treatments
Synergies
- Taurine (1-3g): complements glycine in mitochondrial protection
- Magnesium glycinate: provides extra glycine + magnesium
- Resistance training: GlyNAC improves muscle mass when combined with exercise
- Intermittent fasting: glutathione depletes during fasting; GlyNAC replenishes it
GlyNAC vs other longevity stacks
| Precio |
“GlyNAC is the longevity stack with the best evidence-to-cost ratio after creatine. A human clinical trial reversing 8 aging markers at $10/month. Needs more replication, but the safety profile allows starting now.”
Buy in the US
NOW Foods Glycine Powder (454g)Amazon NOW Foods NAC 600mg (250 capsules)AmazonLas fuentes incluyen instituciones médicas, revistas peer-reviewed y organizaciones de investigación. Aevum no ofrece consejo médico.
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