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Sarcosine
Sarcosine (N-methylglycine) is a GlyT1 inhibitor + NMDA glycine-site partial agonist with A-tier evidence as a schizophrenia adjunct (Tsai…
Aliases (6)
Overview
What is Sarcosine?
Sarcosine (N-methylglycine) is an endogenous amino acid derivative and a glycine transporter type 1 (GlyT1) inhibitor. It is investigated as an adjunct in schizophrenia (negative/cognitive symptoms) and depression by enhancing NMDA receptor function via the glycine co-agonist site.
Key Benefits
Improves negative and cognitive symptoms of schizophrenia in clinical trials, shows antidepressant effects (often faster-acting than SSRIs in small studies), and may enhance learning and memory through NMDA receptor potentiation.
Mechanism of Action
Inhibits glycine transporter type 1 (GlyT1), raising synaptic glycine concentrations near NMDA receptors. This increases occupancy of the glycine co-agonist site on the NMDA receptor, enhancing glutamatergic transmission and downstream neuroplasticity.
Pharmacokinetics
▸ Mixing & scoop math Powder
- • Mix into 8-16 oz cold water (or sports drink / protein shake). Most powders dissolve in < 30 sec with a brisk stir.
- • If using a shaker, add liquid first, then powder, then shake — minimizes foam and clumps.
- • Hot water is fine for most amino acids and creatine; avoid for heat-sensitive compounds (NAC degrades above ~60 °C).
- • Drink within 5-10 min of mixing — most powders are stable in solution but taste degrades.
Research Indications
1. GlyT1 (glycine transporter 1) inhibition — the primary mechanism
GlyT1 (SLC6A9) is a Na⁺/Cl⁻-dependent transporter expressed predominantly on astrocytes surrounding glutamatergic synapses (with smaller …
2. NMDA receptor glycine-site partial agonism
Sarcosine has weak intrinsic agonist activity at the NMDA receptor glycine-binding site (GluN1 subunit) in addition to its GlyT1 inhibiti…
3. Why this matters less in healthy adults
The NMDA glycine site is approximately saturated under normal physiological conditions in healthy adults (synaptic glycine + D-serine are…
4. Other mechanistic notes
- Sarcosine is metabolized by sarcosine dehydrogenase (SARDH) in mitochondria back to glycine (oxidative N-demethylation, releasing CH₂O …
Peptide Interactions
well-evidenced clinical synergy in schizophrenia. Not relevant to the user.
overlapping mechanism (all raise NMDA glycine-site activation). Not commonly stacked clinically; sarcosine is the more efficient single agent. Not relevant t…
mechanistically complementary in schizophrenia (NAC modulates glutamate release via cystine-glutamate antiporter; sarcosine enhances NMDA receptor function).…
mechanistically *opposed* (memantine is an NMDA antagonist). Rarely co-prescribed; mechanistic conflict. Not relevant.
the canonical "avoid" interaction. Multiple trials and meta-analyses show sarcosine does not augment clozapine and may antagonize clozapine's effect on negat…
(memantine, ketamine, dextromethorphan at high doses, PCP analogs) — mechanistic opposition. Don't co-administer for therapeutic purposes; recreational/resea…
no documented interaction, but caution warranted in any glutamatergic-modulator combination with monoamine oxidase inhibition.
Quality Indicators
Single-ingredient, COA-backed
Look for single-ingredient powders from vendors who publish a Certificate of Analysis.
Mixes cleanly
Should dissolve or suspend cleanly in water without large clumps once stirred.
Off taste or smell
Strong rancid, fishy, or chemical odors can indicate oxidation or contamination.
Color or texture change over time
A powder that yellows, clumps, or hardens over time may be hygroscopic and degraded.
What to Expect
- Onset30-90 min after dose. Effects, when present, are subtle.
- Peak1-3 hours. Plasma half-life ~1-2 hours; subjective effect window 2-4 hours.
Side Effects & Safety 5
Side Effects
- 1None reliably at 1-2 g/day in healthy adults. Most users report nothing.
- 2Mild GI (loose stool, bloating, mild nausea) at doses >1 g; usually resolves with split dosing or food.
- 3Mild sleepiness or fogginess in a small subset; mechanism unclear, possibly elevated synaptic glycine in brainstem nuclei.
- 4Mild sweet taste with powder (sarcosine is mildly sweet, related to glycine's sweetness).
- 5Vivid dreams (rare; reported in some users).
When to Stop
- No serious adverse effect signal at typical 1-2 g/day doses across thousands of patient-weeks of schizophrenia trial exposure.
- Schizophrenia trials at 2 g/day for 6+ months showed no organ toxicity, no liver/kidney signal, no hematologic concern.
- Theoretical: in a patient with undiagnosed NMDA hyperfunction state (rare; possibly some seizure phenotypes), boosting NMDA activity could lower seizure threshold. No documented cases at supplement doses, but a relative caution in patients with epilepsy.
- Theoretical: clozapine antagonism — see Drug interactions (clinical, not safety per se, but worth flagging).
- None. Sarcosine has one of the cleaner safety profiles in the NMDA-modulator space.
- No formal UL. Doses up to 4 g/day have been used in some schizophrenia protocols without dose-dependent toxicity.
- Practical ceiling: 2 g/day for healthy-adult experimentation; no rationale to exceed.
References
Tsai et al. 2004 — Glycine transporter I inhibitor, N-methylglycine (sarcosine), added to antipsychotics for the treatment of schizophrenia (Biological Psychiatry)
Foundational positive RCT.
View StudyLane et al. 2005 — Sarcosine or D-serine add-on treatment for acute exacerbation of schizophrenia (Biological Psychiatry)
Sarcosine vs D-serine vs placebo head-to-head.
View StudyLane et al. 2008 — Sarcosine (N-methylglycine) treatment for acute schizophrenia: a randomized, double-blind study (Biological Psychiatry)
Monotherapy demonstration.
View StudySingh & Singh 2011 — Meta-analysis of the efficacy of adjunctive NMDA receptor modulators in chronic schizophrenia (CNS Drugs / Schizophrenia Bulletin)
Sarcosine adjunct meta-analysis with clozapine-exclusion finding.
View StudyStrzelecki et al. 2014, 2015 — Sarcosine adjunct therapy in stable schizophrenia (Pharmacological Reports)
Polish replication, longer-duration tolerability.
View StudyTsai & Lin 2010 — Strategies to enhance N-methyl-D-aspartate receptor-mediated neurotransmission in schizophrenia (Curr Pharm Des)
Mechanism review.
View StudyHuang et al. 2013 — Sarcosine as a treatment for major depressive disorder (Biological Psychiatry)
MDD outlier trial.
View StudySreekumar et al. 2009 — Metabolomic profiles delineate potential role for sarcosine in prostate cancer progression (Nature)
Original prostate-cancer biomarker paper (subsequently walked back).
View StudyCoyle 2006 — Glutamate and schizophrenia: beyond the dopamine hypothesis (Cell Mol Neurobiol)
NMDA-hypofunction hypothesis review.
View StudyCubelos et al. 2005 — Localization of GlyT1 transporter at glutamatergic synapses (Cereb Cortex)
GlyT1 anatomy / mechanism.
View StudyBitopertin Phase III failure summaries (multiple, 2014-2015)
Context for synthetic GlyT1 inhibitor failures.
View StudyHow was your experience with this compound?
Anonymous · one vote per session · results below at 5+ votes.
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