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Clinical trials have found no link between simvastatin and weight gain. Some people, however, report weight gain directly after taking the drug. Although this may tentatively suggest a link between the drug and weight gain, it is generally considered to be related to factors other than the drug itself. Clinical trials are designed to reduce variables that could affect results, and these have consistently found that simvastatin and weight gain are not related. It is worth noting that an underactive thyroid gland can cause weight gain and high cholesterol, for which simvastatin is often prescribed.
High levels of cholesterol can lead to many conditions, including heart disease and atherosclerosis, which is characterized by narrower and harder arteries. Two types of cholesterol exist, and these can simply be thought of as “good” cholesterol and “bad” cholesterol. “Good” cholesterol, or high density lipoprotein (HDL), removes cholesterol from the blood and takes it back to the liver, which protects against the possible negative results of high cholesterol. “Bad” cholesterol, or low density lipoprotein (LDL), is responsible for all of the negative effects of cholesterol because it clogs the arteries.
Simvastatin blocks the action of the HMG-CoA reductase enzyme, which is responsible for the creation of LDL cholesterol. The levels of cholesterol in the liver are reduced, which prompts the liver to remove even more from the blood, thereby reducing the risk of conditions such as heart disease. As well as this, simvastatin also reduces the amount of triglycerides in the blood, which are other harmful fats in the body. These facts all combine to demonstrate that a link between simvastatin and weight gain is unlikely. Bad diet is a common cause of high cholesterol, which simvastatin is prescribed to treat, therefore if the patient’s diet doesn’t change, they will continue to gain weight while taking the drug.
An underactive thyroid gland causes weight gain in many patients, and as a result of this, levels of LDL cholesterol are often increased. This may lead to a physician prescribing simvastatin to patients who are suffering from an underactive thyroid. If the patient’s diet isn’t changed when they begin to take the drug, the weight gain associated with the underactive thyroid is likely to continue. This may lead to some erroneous links being formed between simvastatin and weight gain. Other “statins” have been found to cause weight gain in some instances, but medical science does not consider there to be a link between simvastatin and weight gain.