Betaine (TMG / Trimethylglycine) vs Caffeine (Anhydrous)

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)

Best Stacking Partners

Mechanism

Caffeine is a methylxanthine that primarily acts as a competitive adenosine A1 and A2A receptor antagonist. By blocking adenosine's inhibitory effects on neural activity, caffeine increases alertness, reduces perceived exertion, and delays fatigue. Downstream effects include: increased dopamine, norepinephrine, and acetylcholine release; enhanced calcium release from sarcoplasmic reticulum (direct muscle contraction enhancement); increased fat oxidation via enhanced lipolysis (HSL activation through cAMP/PKA pathway from PDE inhibition); and central drive enhancement (reduced RPE). Caffeine also inhibits phosphodiesterase (PDE), raising intracellular cAMP.

Standard Dosing

100-400mg daily (1-3mg/kg bodyweight for cognitive; 3-6mg/kg for athletic performance)

Timing

30-60 min before exercise or cognitive demand. Avoid within 8-10 hours of bedtime (half-life: 5-6 hours, but CYP1A2 polymorphisms cause wide variation). Morning preferred.

Cycle Duration

ongoing with periodic tolerance resets (1-2 weeks off every 8-12 weeks)

Side Effects

• Insomnia
• Anxiety/jitteriness
• Tachycardia/palpitations
• GI upset/acid reflux
• Dependency/withdrawal headaches
• Increased blood pressure (acute)
• Diuresis
• Tremor

Contraindications

• Uncontrolled hypertension
• Cardiac arrhythmias (especially SVT)
• Anxiety disorders (GAD, panic disorder)
• Pregnancy (>200mg/day associated with increased miscarriage risk)
• GERD/peptic ulcer disease

Best Stacking Partners