Labdoor analyzed 10 best-selling glutamine supplements in the United States for glutamine content and heavy metal (arsenic, cadmium, lead, mercury) contamination.
Overall, measured glutamine deviated from label claims by an average of 3.5%. Products measured an average glutamine concentration of 97.3%, ranging from 89.3% to 99.8%. Research is currently inconclusive about glutamine's effectiveness for exercise performance. Dosing usually begins at 70 mg per kg body weight (4.9 g in a 70 kg individual), although products in this batch do not standardize to this amount in serving size recommendations. All tested products passed heavy metal screens for arsenic, cadmium, lead, and mercury, and recorded glutamine levels per serving well within safe limits.
Analytical Chemistry Methods: HPLC (High Performance Liquid Chromatography) to quantify glutamine levels; ICP-MS (Inductively Coupled Plasma - Mass Spectrometry) to quantify heavy metal (arsenic, cadmium, lead, mercury) load.