Glycine
Glycine is an amino acid that acts as an inhibitory neurotransmitter, similar to GABA. Huberman discusses its role in sleep, collagen synthesis, and as a potential supplement for improving sleep quality.
What Glycine Does
| Function | Mechanism |
|---|---|
| Inhibitory neurotransmission | Calms neural activity |
| Sleep quality | May lower core body temperature |
| Collagen synthesis | Essential building block |
| Methylation | Methyl donor in metabolic pathways |
| Glutathione production | Precursor for this antioxidant |
Glycine and Sleep
Research suggests glycine can improve sleep:
How It Works
- Glycine crosses the blood-brain barrier
- Acts on glycine receptors in the brain
- May lower core body temperature (important for sleep onset)
- Activates NMDA receptors (at low doses, paradoxically calming)
Research Findings
- 3g before bed improved subjective sleep quality
- Reduced daytime sleepiness
- Improved cognitive performance next day
- May help with sleep efficiency
As Part of Sleep Stack
Some include glycine in a sleep protocol:
| Component | Amount | Role |
|---|---|---|
| Magnesium (threonate/glycinate) | 300-400mg | Relaxation, GABA support |
| L-Theanine | 100-400mg | Calm without sedation |
| Apigenin | 50mg | GABA enhancement |
| Glycine | 2-3g | Temperature regulation |
Can be combined or used individually based on response.
Collagen and Joint Health
Glycine is 33% of collagen by amino acid content:
- Essential for collagen synthesis
- Supports skin, joints, tendons
- May enhance collagen supplementation
- Works with proline and vitamin C
Some take glycine specifically for joint and tissue health.
Dosing
| Use | Dose | Timing |
|---|---|---|
| Sleep | 2-3g | 30-60 min before bed |
| Collagen support | 2-5g | With vitamin C |
| General | 1-3g | Any time |
Glycine has a slightly sweet taste and dissolves easily.
Safety
Generally very safe:
- Amino acid naturally present in food
- No significant side effects at typical doses
- May cause mild stomach upset in sensitive individuals
- Very high doses (>10g) may cause soft stools
Food Sources
Glycine is found in:
- Collagen-rich foods (bone broth, skin, connective tissue)
- Gelatin
- Meat, fish
- Legumes
Those eating collagen-rich foods may get adequate glycine from diet.
Related Pages
“Glycine is interesting because it’s both a building block for tissue and an inhibitory neurotransmitter. It may help with sleep through its temperature-lowering effects.” — Andrew Huberman