Phentermine vs Xenical: Get Familiar with Options

Therapeutically, Phentermine and Xenical are similar medications: they both are indicated for tackling the problem of excess weight and obesity.

Pharmacologically, they are totally different as they belong to two different groups of drugs. The latter aspect is decisive, as different mechanisms of action produce different pharmacological effects.

Phentermine and Xenical Active Ingredients


Phentermine is an anorexiant structurally similar to AMPHETAMINE. As such it works by suppressing appetite primarily. Additionally, it increases the metabolism this way helping to split fat tissues. In general, Phentermine, as all diet drugs, is recommended in a combination with physical activity and healthy diet. In particular, it is perfectly able to produce the required effect even at fairly low physical activity.


ORLISTAT (an active ingredient of Xenical) is a gastrointestinal lipase inhibitor, the major function of which is to reduce the levels of lipase. The mechanism of action that Orlistat is primarily known for lies in preventing/reducing the absorption of fats contained in the foods consumed. In other words, it reduces calorie intake. Similarly to Phentermine, Orlistat (Xenical) is combined with a healthy diet and exercises.

Why the Two Are Being Opposed

There are two major diet medications that prevail on the market of weight loss products: Phentermine and Xenical are two of those.These cover a major part of all prescriptions written out for obesity. People suffering from such a problem, if taking one drug, are usually interested in either alternative or combinability. Asking about the options available (various forums are full of such questions) patients rate both medications as well. And Phentermine seems to be ahead of Xenical.

The Mechanism of Action Is Decisive

Among the names that define the class of drugs Xenical belongs to you may find the following: peripherally acting antiobesity agents.

These are the drugs that assist with the problem of obesity/excess weight. Working in the gastrointestinal tract only (no suppressing the appetite properties produced by affecting the chemicals in the brain) Xenical blocks fat absorption moderately; for some patients such a mechanism of action may seem unproductive.

For that reason they often consider a possibility of either shifting to Phentermine or adding that drug to the overall therapy with Xenical.

As for shifting to Phentermine, the mechanism of action is not the only factor that matters. As for combining Xenical with Phentermine, regarded pharmacy resources don’t provide information concerning possible interactions. Thus, an issue like this should be discussed with a doctor who is in charge of the entire weight loss program.

Duration of the Therapy Course and Drugs Cost

The latest rating figures concerning Phentermine-Xenical opposition represent the former as the leader: satisfaction score taken by Phentermine is 3.1 to 2.9 achieved by Xenical. Two more factors that contribute to higher rating given to Phentermine before Xenical are the overall duration of the treatment and expenses involved.

Phentermine is prescribed for a short term only (maximum within 12 weeks in a row).

Xenical can be taken for a long time. In certain cases therapy with Xenical may take as much as up to two years, so that a desired weight loss result could reveal itself.

This may involve really high expenses, as Xenical is more expensive than Phentermine.

Leave a Reply

Notify of