All the substances in O2 are natural ones. O2 does not contain any alcohol or glucose, or any substance that is on the “banned list of substances” regarding international, professional and amateur athletic associations. O2 is made from the finest natural substances which are cryogenically (extreme cold), not chemically extracted; and are totally non-toxic. We only use high quality vegetal Silica from a 100% pure aqueous extract. If a person has allergies, it is highly unlikely that using O2 would cause any adverse effects; however, it is recommended that people with allergies contact a Health Care Practitioner with knowledge and understanding of O2.