Glycine vs Magnesium Glycinate

Mechanism

Glycine is the simplest amino acid with profound neurological and metabolic roles. It is an inhibitory neurotransmitter acting at glycine receptors (strychnine-sensitive) in the brainstem and spinal cord, inducing a drop in core body temperature that facilitates sleep onset. It is also an obligatory co-agonist at the NMDA receptor glycine binding site, modulating excitatory neurotransmission. Metabolically, glycine is the rate-limiting amino acid for glutathione synthesis (glutathione = glycine + cysteine + glutamate), a key substrate for collagen synthesis (every 3rd amino acid), essential for creatine synthesis, bile acid conjugation, heme synthesis, and one-carbon metabolism.

Standard Dosing

3-5g daily

Timing

3g before bed for sleep (core body temperature reduction). Divided doses during day for glutathione support. Powder in water has a mildly sweet taste.

Cycle Duration

ongoing

Side Effects

• Mild drowsiness
• Soft stools at high doses
• Nausea (rare)
• Generally extremely well-tolerated

Contraindications

• Very few absolute contraindications. Caution in severe renal disease.

Best Stacking Partners

Mechanism

Magnesium is a cofactor for >600 enzymatic reactions including all ATP-dependent reactions (Mg-ATP is the true substrate), DNA/RNA polymerases, and ion channel regulation. Magnesium glycinate chelate provides highly bioavailable elemental magnesium bound to glycine. The glycine moiety itself is an inhibitory neurotransmitter (glycine receptors) and NMDA receptor co-agonist at the glycine binding site. The chelated form minimizes the osmotic laxative effect of ionic magnesium salts. Magnesium regulates NMDA receptor gating (voltage-dependent Mg2+ block), GABA-A receptor potentiation, HPA axis modulation, and parathyroid hormone secretion.

Standard Dosing

200-400mg elemental magnesium daily

Timing

Evening/bedtime (promotes relaxation and sleep quality). Can split AM/PM.

Cycle Duration

ongoing

Side Effects

• Drowsiness
• Mild GI discomfort
• Loose stools (less than other Mg forms)
• Hypotension at very high doses

Contraindications

• Severe renal insufficiency (impaired Mg excretion — risk of hypermagnesemia)
• Myasthenia gravis (Mg can worsen neuromuscular junction blockade)
• Heart block (Mg slows AV conduction)

Best Stacking Partners