Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| GABA (Gamma-Aminobutyric Acid) | L-Tyrosine | |
|---|---|---|
| Category | Amino Acids | Amino Acids |
| Standard Dose | 250-750mg daily | 500-2000mg daily |
| Timing | Evening before bed for sleep, or as needed for acute anxiety/stress. Sublingual onset: 15-20 minutes. | Morning on empty stomach (competes with other large neutral amino acids for BBB transport). 30-60 min before stressful tasks or exercise. |
| Cycle Duration | As needed or cycle 4-8 weeks on, 2 weeks off | As needed or cycle 4-8 weeks on, 2 weeks off |
| Evidence Level | moderate_human | strong_human |
GABA is the primary inhibitory neurotransmitter in the CNS, activating GABA-A receptors (ligand-gated chloride ion channels, causing rapid inhibition) and GABA-B receptors (G-protein coupled, causing slow, sustained inhibition). Supplemental GABA's ability to cross the blood-brain barrier is debated — it likely acts primarily through the enteric nervous system (gut-brain axis), peripheral GABA receptors, and potentially via limited BBB penetration at the circumventricular organs. GABA promotes alpha brain waves (relaxation), increases growth hormone secretion (via GHRH modulation), and reduces sympathetic nervous system overactivation.
250-750mg daily
Evening before bed for sleep, or as needed for acute anxiety/stress. Sublingual onset: 15-20 minutes.
As needed or cycle 4-8 weeks on, 2 weeks off
L-Tyrosine is the precursor amino acid for catecholamine neurotransmitter synthesis: tyrosine hydroxylase converts tyrosine to L-DOPA (rate-limiting step), which is then converted to dopamine, norepinephrine, and epinephrine. It is also the precursor for thyroid hormones (iodination of tyrosine residues on thyroglobulin produces T3/T4) and melanin (via tyrosinase). Under conditions of acute stress, catecholamine turnover increases dramatically, depleting brain tyrosine pools. Supplementation provides substrate to maintain catecholamine synthesis during stress, sleep deprivation, cold exposure, and cognitive demand.
500-2000mg daily
Morning on empty stomach (competes with other large neutral amino acids for BBB transport). 30-60 min before stressful tasks or exercise.
As needed or cycle 4-8 weeks on, 2 weeks off
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