There are a number of products on the market - both prescription and non-prescription - which claim to be effective weight loss aids. Many of these have been associated with serious medical risks, including heart attack, heart abnormalities, tachycardia, stroke, seizures and death. The side effects can be daunting, but how realistic are they?

Diet pills fall into several different classes. Most are appetite suppressants of one kind or another, generally stimulants with effects similar to those of amphetamine. They are approved for treatment of obesity, where it's considered that the health risks associated with gross overweight outweigh the risks associated with the medication.

For someone who has less than 30 pounds to lose, the risks are far less cut-and-dry. While the FDA and manufacturers closely monitor the effects of prescription weight loss medications, over the counter medications and their risks are far less documented. Herbal supplements are even less documented still, especially those whose makers don't officially make weight loss claims for them.

While makers of pharmaceuticals must meet stringent labeling requirements and tests for safety and effectiveness, those who make weight loss 'supplements' are not regulated in the same way. As long as they don't contain a 'new' ingredient, or one that has never been marketed for weight loss purposes, they are not subject to FDA review. Instead, the manufacturer is held responsible for the safety and effectiveness of their products. Often, that means unregulated dosages, unhealthy additives and ineffective ingredients.

In an effort to encourage improvement in the reporting standards and the pharmaceutical standards for weight loss medications, the United States Pharmacopoeia has introduced the Comprehensive Dietary Supplement Verification Program. Currently voluntary, it involves certification by the USP of certain labeling and practice standards, including that the product contains the ingredients stated on the label in the strength declared, that they are within limits for impurities like metals, pesticides and bacteria, that the medication will be absorbed by the body according to USP criteria, and that it has been created with all safe precautions.

Until the day that all over the counter medications and herbal preparations marketed as weight loss supplements and aids are labeled and tested by impartial researchers, there are some things that you can do to lessen the risks associated with using diet pills.

Research is your best friend. There's a lot of information out there about drugs and herbs like ephedra, ephinedrine, phentermine and sibutramine. Know what you're taking and what the risks are so that you can watch for side effects.

Always talk to your doctor before you start taking any drug or herbal supplement. Many of them interact poorly with other medications, or have an adverse effect on chronic conditions.

Follow dosage instructions. Overdoses of stimulant medications, which are a component of most weight loss preparations, can be serious and severe.

Don't take any weight loss pill or supplement for more than a few weeks without it being prescribed by a doctor.

Check with your pharmacist when purchasing over the counter weight loss preparations to be sure that the ingredients don't interact with other medications you may be taking. Include both prescription and nonprescription medications in your questions.

Ideally, don't take weight loss pills. The effectiveness of most have not been proven at all. It's an awful lot of risk for such a little loss.