Quick Comparison
| Glycine | Reishi | |
|---|---|---|
| Half-Life | 1-2 hours (plasma) | Bioactive compounds accumulate with daily use |
| Typical Dosage | For sleep: 3 g taken 30-60 minutes before bed. For general nootropic use: 1-3 g daily. For NMDA co-agonism (with racetams): 1-3 g daily. Sweet taste, dissolves easily. | Standard: 1000-3000 mg daily of extract. Dual-extract (water + alcohol extraction) preferred to capture both polysaccharides and triterpenes. Take in the evening due to calming effects. Spore oil: 500-1000 mg daily. Effects build over 2-4 weeks. |
| Administration | Oral (powder, capsules). Sweet-tasting powder dissolves easily in water. | Oral (capsules, powder, tincture, tea). Dual-extract preferred. Bitter taste in powder/tea form. |
| Research Papers | 10 papers | 8 papers |
| Categories |
Mechanism of Action
Glycine
Glycine acts as an inhibitory neurotransmitter by binding to strychnine-sensitive glycine receptors (GlyR) in the brainstem, spinal cord, and retina, hyperpolarizing neurons via chloride influx. It also serves as a mandatory co-agonist at the glycine-binding site (NR1 subunit) of NMDA glutamate receptors — without glycine binding, NMDA receptors cannot open their ion channel even when glutamate is present. This dual role means glycine both calms neural activity (sleep, anti-anxiety via GlyR) and supports excitatory learning processes (NMDA-dependent LTP and memory consolidation). Glycine lowers core body temperature at night by promoting peripheral vasodilation through nitric oxide, which improves sleep onset. It is a precursor for glutathione synthesis and modulates the glycinergic system in the suprachiasmatic nucleus.
Reishi
Reishi's triterpenes (ganoderic acids A, C, D, H; ganoderenic acids) modulate the HPA axis by reducing CRH and ACTH release, lowering cortisol via glucocorticoid receptor feedback. Ganoderic acids have direct sedative effects through GABA-A receptor modulation (possibly allosteric at the benzodiazepine site) and 5-HT2A/2C serotonergic modulation. Beta-(1,3)-(1,6)-glucan polysaccharides bind Dectin-1 and complement receptor 3 (CR3) on macrophages, natural killer cells, and dendritic cells, activating NF-kB and MAPK signaling for immune modulation. Reishi inhibits histamine release from mast cells via Fc epsilon RI downregulation and stabilizes mast cell membranes (anti-allergic effect). Antioxidant properties involve upregulation of superoxide dismutase (SOD1/SOD2), catalase, and glutathione peroxidase. Ganoderic acids may also inhibit 5-alpha-reductase and ACE.
Risks & Safety
Glycine
Common
Essentially none at standard doses. Sweet taste makes it easy to take.
Serious
None documented. One of the safest supplements available.
Rare
Nausea, soft stools at very high doses (>10 g).
Reishi
Common
Digestive discomfort, dry mouth, dizziness.
Serious
Rare hepatotoxicity reported — avoid with liver disease. May interact with blood thinners and immunosuppressants.
Rare
Allergic reaction, nosebleeds.
Full Profiles
Glycine →
The simplest amino acid, yet one of the most important for brain function and sleep quality. Glycine is an inhibitory neurotransmitter (like GABA), a co-agonist at NMDA receptors (enhancing learning), and a critical building block for glutathione (the body's master antioxidant). Taking 3g before bed reliably improves sleep quality and next-day cognitive performance.
Reishi →
Known as the 'mushroom of immortality' in Chinese medicine, Reishi (Ganoderma lucidum) is an adaptogenic mushroom primarily used for stress reduction, immune support, and sleep improvement. Unlike the stimulating effects of Cordyceps or Lion's Mane, Reishi is calming and is best taken in the evening. Its triterpene compounds modulate the HPA axis and support GABAergic relaxation.