An amino acid involved in the synthesis of proteins, DNA and collagen. Provides antioxidant protection, affects the quality of sleep, thermoregulation and the nervous system. Deficiency may reduce stress resistance and impair tissue repair.
Normal range: 150–450 µmol/l
Reasons for increased values: metabolic disorders, renal failure
Reasons for decreased values: protein deficiency, metabolic disorder, increased needs
Is a source of nitric oxide, regulates vascular tone and microcirculation. Participates in tissue healing, immune system function and growth hormone synthesis. With a deficiency, regeneration processes, blood circulation and adaptation to stress may be disrupted.
Normal range: 40–120 µmol/l
Reasons for increased values: impaired urea metabolism, tumors
Reasons for decreased values: protein starvation, inflammation, physical exhaustion
The main source of energy for intestinal cells and the immune system. Participates in protein synthesis, regulation of acid-base balance and tissue restoration. Decreased glutamine levels weaken protective barriers and can impair recovery from stress.
Normal range: 400–900 µmol/l
Reasons for increased values: stress, metabolic disorders
Reasons for decreased values: infectious diseases, surgeries, catabolism
A sulfur-containing amino acid necessary for the synthesis of glutathione, one of the main antioxidants. Affects the condition of the skin, hair, nails, and detoxification processes. Deficiency may affect liver function, antioxidant protection, and tissue structure.
Normal range: 10–140 µmol/l
Reasons for increased values: oxidative stress, sulfur metabolism disorders
Reasons for decreased values: deficiency of sulfur-containing proteins, antioxidants
Supports heart function, regulates water-salt balance, stabilizes the nervous system, and protects cells from stress. Important for vision and development of the nervous system. A decrease in levels may manifest itself in rhythm disturbances, fatigue, and deterioration in adaptation.
Normal range: 40–120 µmol/l
Reasons for increased values: diabetes, liver or kidney pathology
Reasons for decreased values: stress, metabolic disorders, deficiency in the diet
A precursor of carnosine, which accumulates in muscles and reduces acidity during physical exertion. Increases endurance, helps muscle recovery, and protects against fatigue. A deficiency may reduce physical performance and cause fatigue.
Normal range: 0.5–4 µmol/l
Reasons for increased values: intense physical activity
Reasons for decreased values: low protein intake, muscle wasting



