Glycine
The smallest amino acid with the biggest resume. Glycine is used to make glutathione, collagen, creatine, bile acids, and heme. It's also a calming neurotransmitter that improves sleep. Modern diets are often deficient.
What Glycine Does
Glutathione Synthesis
One of three amino acids (with glutamate and cysteine) that form your master antioxidant.
Collagen Production
Every third amino acid in collagen is glycine. No glycine = no collagen.
Creatine Synthesis
Combines with arginine in the first step of making creatine for muscles and brain.
Bile Acid Conjugation
Glycine conjugates bile acids for fat digestion and toxin elimination.
Heme Synthesis
Glycine + succinyl-CoA = ALA, the first step in making heme for blood.
Neurotransmitter
Inhibitory neurotransmitter in spinal cord. NMDA receptor co-agonist in brain.
Why Modern Diets Are Glycine-Deficient
Our ancestors ate the whole animal - skin, bones, tendons, cartilage. These collagen-rich parts are loaded with glycine. Modern diets focus on muscle meat, which is low in glycine and high in methionine.
This creates a glycine:methionine imbalance. We need roughly equal amounts, but muscle meat has 3x more methionine. Excess methionine without glycine increases homocysteine and stresses methylation.
Glycine-Rich Foods
- • Bone broth (6-12g per cup)
- • Collagen peptides (3g per 10g scoop)
- • Gelatin (same as collagen)
- • Pork skin/rinds
- • Chicken feet, beef tendon
- • Supplemental glycine powder
Glycine for Sleep
Taking 3g of glycine before bed improves sleep quality. It works by lowering core body temperature - the same signal that naturally initiates sleep.
Faster Sleep Onset
Fall asleep more quickly
Deeper Sleep
More time in restorative slow-wave sleep
Better Next-Day Function
Less daytime fatigue, better cognition
How to Use for Sleep
- •Take 3g (3000mg) 30-60 minutes before bed
- •Dissolve in water - it's sweet and pleasant tasting
- •Can combine with magnesium for enhanced effect
- •Very safe - no grogginess, no tolerance
- •Works on first night, no buildup needed
Glycine in the Methylation Cycle
Serine → Glycine
SHMT converts serine to glycine, donating carbon to folate
Glycine Cleavage
Mitochondrial system breaks down glycine for one-carbon units
Glycine → Sarcosine
GNMT methylates glycine, buffering excess SAMe
Methyl Buffer
Glycine can absorb excess methyl groups when needed
Signs You May Need More Glycine
Poor Sleep
Trouble falling asleep or staying asleep
Joint Issues
Stiff, creaky, or painful joints
Poor Wound Healing
Slow recovery from cuts and injuries
Detox Problems
Trouble with phase 2 detoxification
