The best time to take simvastatin is in the evening. This is because your body makes most of its cholesterol at night when you are not eating. One study that measured people’s total cholesterol and low-density lipoproteins found that concentrations of these two lipids were significantly lower when simvastatin was taken in the evening, than when it was taken in the morning.

Other studies that have investigated atorvastatin, have found no difference in total cholesterol and LDL concentrations between taking it in the morning or taking it at night. This may be explained by its longer elimination half-life, which means it lasts longer in the body than simvastatin.

Take simvastatin in the evening. Simvastatin does not upset your stomach, so you can take it with or without food but swallow the tablets whole with a glass of water.

Do not drink grapefruit juice while you’re taking simvastatin. Grapefruit juice has a big effect on the concentration of simvastatin in your blood because it contains compounds called furanocoumarins that block the effects of CYP3A, an enzyme that works in your liver to break down substances, including simvastatin. This means more simvastatin is absorbed making it more powerful than it's meant to be, which could result in toxic levels in some people.