Ingredients of Metformin

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Metformin is the generic name for the type 2 diabetes medication known by a number of brand names, including Glucophage, Riomet and Fortamet. Metformin decreases the amount of circulating blood glucose, decreases the chance of diabetes complications such as kidney or heart disease, lowers cholesterol levels and can cause a mild amount of weight loss. Metformin consists of the active ingredient metformin hydrochloride, and inactive ingredients that function as anti-caking agents, emulsifiers and delayed release agents.

Metformin Hydrochloride

The active chemical in metformin, metformin hydrochloride, works as an effective non-insulin dependent diabetes treatment in a number of ways: it decreases the amount of glucose produced by the liver, inhibits the absorption of glucose in your stomach and enhances the function of insulin, causing you to burn through circulating glucose faster. Metformin hydrochloride cannot be used as a treatment for insulin-dependent diabetes as it is broken down in the digestive system, destroying the effect of the medication.

Anti-Caking Agents

Silicon dioxide is an inactive ingredient in metformin as a way to prevent the various other compounds in the medication from coagulating or clumping together in uneven amounts throughout the tablet. The silicon dioxide--which has the consistency of very fine sand--helps to create a smooth mixture with which to form the metformin tablets. Magnesium stearate, a magnesium salt with an attached stearic acid, is also used in metformin as an anti-caking agent. Magnesium stearate has the added benefit of lubricant properties: it makes the tablets less sticky, easier to swallow and simpler to pack in bottles.


An emulsifier is a compound that holds ingredients together in a solution or mixture without affecting the properties of any of those individual ingredients. Most pills and tablets contain at least one emulsifiying agent since, without one, the properties of the compounds would often prevent them from mixing together at all. Metformin tablets commonly contain the polymer polyvinylpyrrolidine in order to bind the various components of the medication together.

Delayed Release Agents

Compounds that bind to the ingredients within a tablet or pill and cause them to be released into the body slowly over time are especially useful for medications such as metformin. These compounds prevent overdosing and allow active ingredients to stay at a constant level in the bloodstream until the next dosage. Polyethylene glycol, a compound consisting of repeated links of ethylene glycol units, is commonly added to metformin to regulate the slow release of metformin hydrochloride. The cellulose-based coating used for the metformin tablets, acetophtalic cellulose, also plays a role in regulating the disintegration of the medication in the digestive system.