Glycine vs Modafinil / Armodafinil
Both are used for sleep better. Here's how they compare on human evidence, mechanism, safety and availability — in plain English.
| Glycine | Modafinil / Armodafinil | |
|---|---|---|
| Human evidence | ★★★☆☆ | ★★★★★ |
| Legal status | OTC Supplement | Controlled, Prescription |
| How it works | Smallest amino acid; inhibitory neurotransmitter at spinal/brainstem glycine receptors (GLRA1), lowers core body temperature (a sleep-onset trigger) via peripheral vasodilation, and supplies one-third of collagen's amino acids. Mimics some… | Inhibits the dopamine transporter (SLC6A3/DAT) (weakly, without amphetamine-like euphoria) and activates orexin/hypocretin (HCRT) and histaminergic wake circuits. Armodafinil is the longer-acting R-isomer. |
| In plain English | An amino acid that gently cools you down and quiets the nervous system for sleep, and is the main brick in collagen. Dirt cheap, very safe. | Switches on the brain's "stay awake" system and gently raises dopamine — sharp, sustained alertness without a jittery high or crash. Dramatic if sleep-deprived; subtler if well-rested. |
| Bottom line | One of the most undervalued supplements — sleep + connective tissue + longevity. | The best-evidenced cognitive enhancer in healthy adults; respect the long half-life. |
| Availability | Available over the counter | Controlled substance |
Which is better for sleep better?
Modafinil / Armodafinil has the stronger human-evidence rating (★★★★★ vs ★★★☆☆), but the right choice still depends on your goal, tolerance and budget.
Full breakdowns: Glycine · Modafinil / Armodafinil.
Common questions
Is Glycine or Modafinil / Armodafinil better for sleep better?
Modafinil / Armodafinil has the stronger human-evidence rating (★★★★★ vs ★★★☆☆), but the right choice still depends on your goal, tolerance and budget.
What's the difference between Glycine and Modafinil / Armodafinil?
Glycine: One of the most undervalued supplements — sleep + connective tissue + longevity. — Modafinil / Armodafinil: The best-evidenced cognitive enhancer in healthy adults; respect the long half-life.