Blood test. nothing unusual except magnesium. 1.01 mmol/l (lab range: .7-1.0). any need for follow-up?

No: What you presented is within the normal range. The reference range is central 95% of people, so 5% of normal people will have a value outside that range. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.