So, you're thinking about adding fat burners to your daily routine as a way to help you achieve that slimmer, trimmer body you've always wanted. Hey! Every little bit helps right? So, why not fat burners? Well, here is the low-down on fat burners that just might help you understand what they are and how they work.

While there are quite a number of products on the market today, many of the ingredients in fat burners will be similar from one product to another. Caffeine is a drug that is used all over the world, mostly for its stimulant effects. Caffeine increases alertness, but it lowers the perceived exertion of exercise and decreases reaction time. Caffeine has another effect that few people know about. It also acts as a fat burner! Caffeine works by increasing the rate of fatty acid metabolism and decreasing the rate of carbohydrate metabolism during aerobic exercise. Glycogen is spared after taking in only 150-250mg of caffeine.

With an increased reliance on fat and a decreased reliance on glycogen, more calories will be burned from fat if caffeine is taken in prior to exercise. Keep in mind, caffeine does have some side effects as well. At higher doses, caffeine can cause slowed heart rate, hypertension, nervousness, irritability, insomnia and gastrointestinal distress. It is also a diuretic, which causes the kidneys to excrete more fluid than normal. This dehydrates the body. Caffeine will not help you lose weight on its own, but if taken before aerobic exercise it can help increase fat burning and help you exercise longer.

HCA, or hydroxyl citric acid, has the purported effects of inhibiting the conversion of fat. By blocking the enzyme ATP citrate lyase,it decreases your appetite. Naringin is a substance that is isolated from grapefruit and is an inhibitor of an enzyme that metabolizes caffeine. It has been shown to possibly prolong caffeine's fat burning effects.

Synephrine is the active compound in the fruit of a plant called citrus aurantium. Synephrine is chemically similar to the ephedrine found in many cold/allergy medications and a number of weight loss and energy supplements, which also contain ma huang. Its purported benefits are to increase the metabolic rate, increase calorie expenditure, promote weight loss and increase energy.

Guggulsterone possibly works by stimulating the thyroid gland. This speeds up the metabolism. It may also lower cholesterol. The trouble is, as with many of these herbs, is that they have not been studied enough to prove that they really work or if they are safe from any side effects.

Yohimbine raises your metabolism by increasing the release of norepinephrine, one of the adrenal hormones. Studies have shown that this product did have a weight loss effect, but as with most other products of this kind, long term use and side effects have yet to be studied.

In essence, fat burners may work to some extent, but at what possible long term cost? With the lack of studies on most of these products we don't know there effectiveness or or any of there possible side effects. It would be safe to say, it would be in your best interest to avoid most of these products.

Caffeine, if used in moderate amounts, may well be your best bet for a pre-exercise fat burning aid. But use it sparingly and if you feel any of the previously mentioned side effects or any other symptoms from caffeine use, stop and consult your doctor before continuing use.