Amino acids
The 20 protein-building amino acids. Essential amino acids must come from the diet; non-essential ones the body can make (some only under normal conditions — “conditionally essential”).
Essential
- Histidine Essential HisH Precursor to histamine; supports tissue growth, repair, and the myelin sheath. 🧪 3 sources
- Isoleucine Essential IleI A branched-chain amino acid (BCAA) used for muscle metabolism and energy. 🧪 3 sources
- Leucine Essential LeuL The key branched-chain amino acid that triggers muscle protein synthesis (mTOR). 🧪 3 sources
- Lysine Essential LysK Needed for collagen, carnitine synthesis, and calcium absorption. 🧪 4 sources
- Methionine Essential MetM Sulfur amino acid; a methyl donor and precursor to cysteine. 🧪 5 sources
- Phenylalanine Essential PheF Precursor to tyrosine and the catecholamine neurotransmitters. 🧪 3 sources
- Threonine Essential ThrT Supports collagen, elastin, and immune (antibody) function. 🧪 3 sources
- Tryptophan Essential TrpW Precursor to serotonin and melatonin. 🧪 5 sources
- Valine Essential ValV A branched-chain amino acid (BCAA) for muscle energy and repair. 🧪 3 sources
Non-essential
- Arginine Conditional ArgR Precursor to nitric oxide; conditionally essential during growth, illness, or stress. 🧪 4 sources
- Cysteine Conditional CysC Sulfur amino acid; the rate-limiting building block for glutathione. 🧪 3 sources
- Glutamine Conditional GlnQ The most abundant amino acid; fuels gut and immune cells, conditionally essential when catabolic. 🧪 1 source
- Glycine Conditional GlyG Simplest amino acid; builds collagen and glutathione and acts as a calming neurotransmitter. 🧪 5 sources
- Proline Conditional ProP A major structural component of collagen. 🧪 2 sources
- Tyrosine Conditional TyrY Precursor to dopamine, norepinephrine, and thyroid hormone. 🧪 2 sources
- Alanine Non-essential AlaA Shuttles nitrogen and feeds the glucose–alanine cycle for energy. 🧪 1 source
- Asparagine Non-essential AsnN Involved in ammonia handling and protein synthesis. 🧪 0 sources
- Aspartic acid Non-essential AspD An excitatory amino acid with roles in the urea cycle and energy metabolism. 🧪 1 source
- Glutamic acid Non-essential GluE The main excitatory neurotransmitter (glutamate) and a nitrogen shuttle. 🧪 2 sources
- Serine Non-essential SerS Precursor to glycine and phospholipids; central to one-carbon metabolism. 🧪 1 source