Optimum Nutrition Formula is a potent daily supplement formulated by Patrick Holford to provide optimum amounts of a range of essential nutrients including Vitamin A, Vitamin B complex, Iron, Zinc, Selenium and Chromium and is also particularly high in calcium, magnesium and vitamin D. Recommended Intake - One tablet taken twice daily with food, or as professionally directed. Warning - This product contains vitamin A - Do not take if you are pregnant or if you are likely to become pregnant except on the advice of a doctor or ante-natal clinic.