The B vitamins include B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (Pantothenic acid), B6 (pyridoxamine), B7 (biotin) B9 (folic acid), and B12. They are together or separately involved in most of the body's metabolic processes. The maximum dosage is often scientifically referred to as The Tolerable Upper Intake Level (UL) or the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects most healthy individuals. Intake above the UL increases risk of adverse events. There are not many ULs set for B vitamins because they are water soluble, meaning the body excretes most of what it doesn't use making overdoing on B vitamins difficult but possible with some. Below is what is known about the maximum dose of some of the B vitamins.
Thiamin: There are no reports available of adverse effects from consumption of excess thiamin by ingestion of food and supplements. Because the data are inadequate for a quantitative risk assessment, no Tolerable Upper Intake Level (UL) can be derived for thiamin but stay below 25mgs unless advised by a doctor.
Riboflavin: No adverse effects were reported in humans after single oral doses of up to 60 mg of supplemental riboflavin and there is no UL at this time.
Niacin: although the UL is set at 35mgs because niacin can cause harmless flushing, niacin in the form of niacinamide can be taken in far larger doses but stay below 100mgs
Vitamin B6 (Pyridoxine): 100mgs/day is the UL but stay below 50mgs unless advised by a qualified physician
Folate: the UL for adults is 1 mg/day or 1,000 µg/day
Vitamin B12: No adverse effects have been associated with excess B12 intake from food or supplements in healthy individuals.
Pantothenic acid: No reports of adverse effects of oral pantothenic acid in humans or animals were found and therefore no UL has been set
The goal is to make sure you get proper daily amounts of all necessary B vitamins. This goal is accomplished by eating a healthy diet (as found in the Sharecare Fitness application) and taking a daily multivitamin and mineral formula that contains the necessary B vitamins within the amounts shown below (upper portion of range for active people and/or dieters unless otherwise noted):
• B1: 2-10mg/day
• B2: 5-10mg/day
• B3 (Niacinamide – this form will not cause flushing): 15-30mg/day
• B5: 0-15mgs (women and over 50)
• B6: 6-12mg/day
• B7 (biotin): 100-300mcgs
• Folic acid: 200-400mcg/day
• B12: 12-100mcg