EAAs (Essential Amino Acids) vs HICA

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

Mechanism

Leucine metabolite studied for soreness reduction and anti-catabolic effects during intense training blocks.

Contraindications

• Limited large-scale human data