Betaine (TMG / Trimethylglycine) vs EAAs (Essential Amino Acids)

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

The 9 essential amino acids (leucine, isoleucine, valine, lysine, methionine, phenylalanine, threonine, tryptophan, histidine) cannot be synthesized endogenously and must be consumed. Leucine is the primary mTORC1 activator (via Sestrin2 and CASTOR1 sensors), triggering p70S6K and 4E-BP1 phosphorylation to initiate muscle protein synthesis (MPS). The remaining EAAs are required as substrates for the actual protein synthesis — leucine signals the process, but all 9 EAAs must be present to complete it. EAA supplementation achieves comparable MPS stimulation to whey protein with fewer total calories.

Standard Dosing

6-12g per serving

Timing

Intra-workout (sipped during training) or immediately post-workout. Can also be used between meals to maintain elevated MPS throughout the day.

Cycle Duration

ongoing during training periods

Side Effects

• Mild GI discomfort
• Nausea (if concentrated)
• Bloating
• Generally very well tolerated

Contraindications

• Maple syrup urine disease (branched-chain amino acid metabolism disorder)
• Phenylketonuria (phenylalanine content)
• Severe renal disease

Best Stacking Partners