Fat-burners come and many fat-burners go. Manufacturers have used a plethora of ingredients in an attempt to build the perfect fat-burning product, and every year the list of new additions grows longer. But newer doesn't always
mean better. After experimenting with hundreds of ingredients over the years, we've narrowed the list to 12 of the best fat-burners you can buy.

The Basics
Before you take some hot new herb you can't even pronounce to melt away your blubber, be sure you've got the basics covered. Research shows that the following seven supplements are critical for stoking your fat-burning engines. Stack these first for a couple of weeks.

VITAMIN C
When you look at the laundry list of Vitamin C's abilities — immunity enhancer, wound healer, nitric-oxide (NO) booster — it's apparent that it's a jack-of-all-supplements. So it makes sense that Vitamin C also helps keep off bodyfat. According to scientists at Arizona State University (Tempe), Vitamin C appears to improve the body's ability to burn fat and help reduce fatigue. They found that subjects with higher bodyfat had lower
blood levels of Vitamin C; when test subjects were placed on a diet low in C for four weeks, those getting 500 mg of Vitamin C lost more bodyfat than a placebo group, which experienced decreased fat-burning (11%).
DOSE: Supplement with 500-2,000 mg per day with food.

CARNITINE
This amino acid-like compound synthesized by the body isn't like the typical aminos that the body uses to build proteins (such as leucine, lysine and valine). Made from several amino acids and vitamins, carnitine is used for several functional processes in the body. The one we're concerned with here is the transport of fats into the mitochondria of cells (such as muscle cells), where they're burned for energy. Studies show that carnitine taken before exercise helps the body burn more fat and decreases fatigue.
DOSE: Take 500-2,000 mg in the form of L-carnitine or acetyl-L-carnitine, in the morning before breakfast, 30-6o minutes before workouts and in the evening.

SELENIUM
This trace mineral is critical for thyroid hormone production. Selenium is a component of the enzyme that helps convert the thyroid hormone thyroxine (T4) to triiodothyronine (T3), which is responsible for keeping metabolism elevated. Having inadequate selenium levels can impair thyroid function and promote hypothyroidism, or low levels of thyroid hormones.
DOSE: Supplement with 200-400 mcg a day with food.

CALCIUM
You know this mineral is critical for bone health, and you might have also heard it can help keep off bodyfat. Calcium regulates the hormone calcitriol, which causes the body to produce fat and inhibits fat breakdown. When calcium levels are adequate, calcitriol is suppressed. Calcium further aids fat loss by decreasing the amount of dietary fat absorbed by the intestines. Absorbing less fat is similar to eating less fat, with the added bonus of getting to eat it.
DOSE: Make sure you get adequate calcium by supplementing with about i,000 mg per day with food.

ZINC
Deficiency of this mineral is common in hard-training athletes, especially when they restrict calories to get lean. That's bad news, because low zinc levels lead to low levels of testosterone and insulinlike growth factor-1 (IGF-1). Being low in zinc can also interfere with thyroid hormone production, leading to a lowered metabolic rate and making it harder to drop bodyfat. One study from the University of Massachusetts (Amherst) found that subjects placed on a low-zinc diet had significantly lowered metabolic rates. When they took a zinc supplement (25 mg) for 20 days, their metabolism bumped up to higher levels than before they began the low-zinc diet.
DOSE: Take a zinc supplement such as ZMA on an empty stomach before bed to provide 30 mg of zinc and insurance against slow metabolism syndrome.

GREEN TEA EXTRACT
Today it's almost impossible to find a fat-burner that doesn't include green tea extract — scientific research shows it can help out big-time with fat loss. Green tea contains compounds called catechins, including the main ingredient responsible for its thermogenic (fat-burning) properties, epigallocatechin gallate (EGCG). Green tea's major thermogenic effect comes from this catechin's ability to inhibit an enzyme that breaks down norepinephrine, the neurotransmitter involved in regulating metabolic rate and fat-burning.
DOSE: Although drinking green tea is a great idea, you should still supplement with about 500 mg of green tea extract standardized for EGCG three times daily before meals. Research shows that the catechins from green tea extract are better absorbed by the body than from the tea.

CAFFEINE
Many of the same things said about green tea can be said about caffeine. For one, you can't find a fat-burner that doesn't supply some form of caffeine, and two, taking in supplemental forms is better than drinking it in coffee or other beverages. Whether it's listed as caffeine anhydrous, guarana, di-caffeine malate or caffeine-form green-tea extract, you'll likely find caffeine in most fat-burning products. Caffeine aids fat loss by binding to fat cells to enhance the removal of fat and inhibit its storage. It also facilitates the burning of extra fat during exercise.
DOSE: Go with 100-300 mg of caffeine with your morning meal and 1-2 hours before training.

The Burn Boosters
After you cover your bases with the basic fat-burning supplements above, consider adding some of the following five ingredients to keep your fat-burning furnace stoked. But don't stack these with the basics right from get-go. Losing bodyfat is a gradual process that requires constant prodding to keep the fires burning. Your supplement plan, like your diet, must be progressive — it's best to slowly increase dosages and the supplements you take.

FORSKOLIN
Forskolin is the active compound in the herb coleus forskohlii, a member of the mint family. It enhances fat loss by activating the enzyme adenylate cyclase, which is also involved in testosterone production, leading to events — including activation of the hormone-sensitive lipase — that allow fat stored in fat cells to be broken down for use as fuel. A recent study from the University of Kansas (Lawrence) found that overweight men who took forskolin for 12 weeks lost considerably more bodyfat and experienced higher levels of testosterone than a placebo group. DOSE: Take a supplement providing 20-50 mg of forskolin 2-3 times daily before meals.

EVODIAMINE
This extract from the evodia rutaecarpa fruit works to burn bodyfat by stimulating specific receptors in the central nervous system that boost metabolic rate. Evodiamine also reduces hunger and slows food digestion, which not only keeps you feeling fuller longer but leads to a steady release of glucose into the bloodstream. This helps to maintain insulin levels and prevents insulin spikes, which cause greater fat storage.
DOSE: Supplement with 30-50 mg of evodiamine 2-3 times per day before meals.

SYNEPHRINE
Synephrine is the active ingredient in the plant citrus aurantium, aka bitter orange. Its structure is chemically similar to ephedrine, but it boosts metabolism without elevating heart rate or blood pressure. Synephrine works by stimulating specific receptors on fat cells that increase the breakdown and release of fat, raising the metabolic rate and blunting appetite. That's quite the hat trick for fat loss.
DOSE: Take 200-600 mg of citrus aurantium standardized to 5-20 mg of synephrine, 2-3 times per day before meals.

WAKAME LEAF
Known scientifically as undaria pinnatfida, this brown seaweed contains the active ingredient fucoxanthin, a carotenoid that increases the activity of uncoupling proteins in fat cells. Uncoupling proteins increase the activity of the metabolic machinery in cells, making them burn more fuel to produce adequate energy. In other words, you burn more calories, such as fat, each day. Research from Hokkaido University (Japan) shows that mice and rats that received supplements of fucoxanthin from wakame leaf lost significantly more abdominal fat than test animals getting a placebo. A currently unpublished human clinical trial also found that overweight females given wakame extract had a higher metabolic rate and lost significantly more bodyweight and bodyfat than a placebo group.
DOSE. Look for products that contain wakame extract such as in the trademarked form Xanthigen and take 150-200 mg 2-3 times per day before meals.

RASPBERRY KETONE
This aromatic compound found in red raspberries works in a similar manner to forskolin by activating hormone-sensitive lipase, which causes fat in fat cells to break down and get released so they can be burned for fuel. Research conducted at Ehime University (Japan) reported that subjects taking raspberry ketone orally or by a patch lost more fat than those taking a placebo.
DOSE: Try 100 mg of raspberry ketone twice daily before meals.

taken from MUSCLE & FITNESS MAGAZINE, April 2007