Betaine (TMG / Trimethylglycine) vs Creatine Monohydrate

Mechanism

Betaine (trimethylglycine) serves as a methyl donor in the betaine-homocysteine methyltransferase (BHMT) reaction, converting homocysteine to methionine — this is the alternative methyl cycle pathway (parallel to the folate-dependent methionine synthase pathway). It functions as an osmolyte, protecting cells from osmotic stress by maintaining intracellular water balance (critical for kidney medulla and muscle cells). Athletic performance benefits likely derive from enhanced creatine synthesis (methyl donation), improved power output via osmotic cell protection, and reduced homocysteine-mediated vascular impairment.

Standard Dosing

2500mg (2.5g) daily

Timing

Split AM/PM or pre-workout. When used as methyl donor with NMN/NR, take with the NAD+ precursor.

Cycle Duration

ongoing

Side Effects

• Fishy body odor (TMA production)
• GI upset/diarrhea
• Nausea
• Methionine elevation (theoretical concern with chronic high-dose use in cancer context)

Contraindications

• Trimethylaminuria (fish odor syndrome — impaired TMA metabolism)
• Homocystinuria (under medical management — betaine is actually used therapeutically here, but dosing requires physician oversight)

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Mechanism

Creatine is phosphorylated by creatine kinase to phosphocreatine (PCr), which serves as a rapid phosphate donor to regenerate ATP from ADP during high-intensity, short-duration activity (the phosphagen energy system). This extends maximal effort capacity by 10-20%. Beyond energy, creatine enhances satellite cell activation and myonuclear addition, increases intracellular water retention (cell volumization signals anabolism), upregulates IGF-1 locally in muscle, enhances glycogen supercompensation, and crosses the blood-brain barrier where it supports cognitive function under stress (brain PCr buffer). It also acts as a direct antioxidant, scavenging reactive oxygen species.

Standard Dosing

5g daily (no loading necessary, but loading is faster)

Timing

Post-workout with carbohydrates and protein for optimal uptake (insulin-mediated GLUT4/creatine transporter co-localization). On rest days, any time with a meal. Dissolve in warm water for solubility.

Cycle Duration

ongoing (no cycling necessary — the 'cycling creatine' myth has been debunked)

Side Effects

• Weight gain (1-3 kg from water retention — intracellular, not bloat)
• GI discomfort at high doses
• Muscle cramping (anecdotal, not confirmed in controlled trials)
• Elevated serum creatinine (expected, benign — not indicative of renal damage)

Contraindications

• Pre-existing renal disease (creatinine levels will rise, which is expected and does not indicate kidney damage in healthy individuals)
• Rare: renal tubular disorders

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