Glutamine is subtle to undetectable acutely. Most users report nothing. The signal is what doesn't happen — slightly fewer minor GI complaints during high-volume training, slightly fewer sniffles during a hard training block, slightly less post-session depletion. Onset to felt benefit (if any) is days to weeks.

At higher doses (10-15g) some users report a vague sense of gut comfort or reduced bloat, but this is highly placebo-permeable. No euphoria, no cognitive sharpening, no acute mood change. People who expect a noticeable effect are usually disappointed; this is gut/immune insurance, not stimulation.

The post-exhaustion ammonia-clearance signal (slightly faster cognitive recovery after exhaustion) is real but only detectable in laboratory protocols with reaction-time tests after near-VO2max efforts. Most MMA training will not push Dylan into the ammonia-spike range that makes glutamine supplementation subjectively valuable.

• Tolerance buildup: none documented. Mechanism is substrate-replacement / fuel-provision, not receptor-mediated. The body simply uses what's available; excess is metabolized normally.
• Recommended cycle: None needed for daily 5g use. Block-cycling (only during peak training) is reasonable from a cost-efficacy standpoint, not pharmacological necessity.
• Reset protocol: N/A.

Synergistic with

• n-acetyl-cysteine (NAC): Both contribute to glutathione synthesis (NAC = cysteine donor; glutamine = glutamate donor). NAC is rate-limiting; glutamine helps marginally. Reasonable mitochondrial / antioxidant pair during high training stress.
• glycine: Both are gut barrier supportive amino acids. Glycine has additional sleep, collagen, and methylation roles. Stack-safe; common in "gut healing" protocols.
• taurine: Both osmolyte / cell-volume / mitochondrial-support amino acids. Both daily-safe. Stack-safe.
• alcar: Mitochondrial energy support; ALCAR provides acetyl + carnitine for fatty-acid oxidation; glutamine provides anaplerotic alpha-ketoglutarate. Theoretical synergy for sustained training output; light empirical data.
• Probiotics, zinc carnosine, deglycyrrhizinated licorice: Standard "gut healing" stack. Glutamine is the foundational amino acid in this protocol; the others are complementary.
• EAA / BCAA: Glutamine is technically not in BCAA (leucine, isoleucine, valine), but is included in some "fermented EAA" formulas. No antagonism. Stack-safe.

Avoid stacking with

• Cancer chemotherapy (without oncologist guidance): While glutamine is used clinically for chemo-mucositis, the simultaneous concern about feeding cancer cells means oncologist-led dosing only.
• Lithium, MAOI, high-dose stimulants: No documented direct interaction, but in seizure-prone or psychiatrically unstable individuals the glutamate-precursor mechanism is a theoretical concern. Conservative recommendation: avoid in those populations.
• Active hepatic encephalopathy / advanced cirrhosis: Avoid — ammonia load.

Neutral / safe co-administration

• All V4 stack components: NAC, citicoline, magnesium glycinate + threonate, DHA, PS, curcumin, rhodiola, theanine, glycine, D3+K2, beta-alanine, vitamin C, creatine, taurine.
• All V5 planned stack additions: modafinil, bromantane, Adamax/Semax, ALCAR, apigenin, astaxanthin, l-tryptophan.
• Whey, casein, EAA, BCAA, creatine — all standard sport stacks.

• CYP enzymes: Glutamine is not a notable CYP inducer or inhibitor. No relevant interactions with modafinil, bupropion, or other CYP-metabolized stack drugs.
• Lactulose (used in hepatic encephalopathy): Theoretical antagonism — lactulose reduces ammonia, glutamine could increase it. Avoid.
• Anticonvulsants: No direct interaction; theoretical concern about glutamate elevation in seizure-prone individuals.
• Contraceptives: No documented interaction.
• Cancer therapeutics: Variable; oncologist guidance required.
• Insulin / oral hypoglycemics: Glutamine has mild glucose-modulating effect via gluconeogenesis but is not clinically significant at supplemental doses.

Glutamine metabolism involves glutaminase (GLS, GLS2) and glutamine synthetase (GLUL / GS) plus the transporters SLC1A5 (ASCT2), SLC7A11, and SLC38A2.

• GLS / GLS2: Polymorphisms theoretically alter glutamate generation rate from glutamine. Direct human PGx data on supplementation response is sparse. Mostly studied in cancer biology contexts.
• GLUL (glutamine synthetase): Loss-of-function variants are associated with neonatal glutamine deficiency syndromes (rare). Heterozygous variants in adults likely have negligible clinical relevance for supplementation decisions.
• SLC1A5 / ASCT2: Cellular glutamine uptake transporter. Polymorphisms affect tissue glutamine flux; studied in cancer therapy contexts. No actionable supplementation guidance.
• 23andMe relevance for Dylan: Once results land (~June 5-15, 2026), no specific glutamine variants are in the standard 23andMe panel that would change supplementation decisions. No expected dose modification.

Recommended for Dylan: BulkSupplements powder if going bulk-cheap, or NOW Foods caps via iHerb (already in V4 supplier flow). Cost is trivially small (~$5-10/mo at 5g/day powder).

• Baseline (before starting): None strictly required at 5g/day. If gut-targeting: zonulin, GI-MAP stool panel, dietary symptom log. If immune-targeting: URTI episode count last 6 months.
• During use: URTI frequency self-report. GI symptom log. Plasma glutamine if accessible (rare; mostly research labs). Resting markers (CRP) at 8-12 weeks if high training load.
• Post-cycle: N/A (not cycled). For block-cycle protocol: re-check gut symptoms and URTI frequency in off-blocks vs on-blocks.
• Plasma glutamine (rare, research only): Available via specialty labs (LabCorp/Quest amino acid panel). Useful for documenting overtraining (low plasma glutamine is one of the more reliable overtraining biomarkers) but not actionable for routine use.