However much you religiously workout or follow a diet plan, at some point you’ll probably find yourself browsing health and fitness stores looking for supplements that will accelerate your weight loss. The problem is, who do you trust? We’ve selected the six most popular weight loss supplements and evaluate their true effectiveness for you.

Generally speaking, over-the-counter weight loss supplements will work by; increasing your metabolism so you burn more calories, reducing your appetite so you consume few calories, or reducing the adsorption of what you consume to decrease calorie intake.

Here’s the list of the top five most popular weight loss supplements and our judgements on their effectiveness:

1. Orlistat

What does it do? Orlistat blocks some of the dietary fat you consume from being absorbed in the body. Fat is calorie dense, so by decreasing fat absorption overall caloric intake is reduced, leading to weight loss.

Does it work? Yes, when combined with exercise and diet Orlistat is very effective for further accelerating weight loss1, as well as keeping the weight off for those who have already lost bodyweight2.

In one study, Orlistat use resulted in an average of 69% more weight loss over a year compared to the control group2.

Are there side effects? Yes, and it is advised you only take Orlistat after speaking to a doctor. We do not advise people to purchase Orlistat online and only use it within a supervised setting.

Orlistat should only be used responsibly by adults who combine the drug with a suitable exercise and diet plan.

Orlistat should not be used if you are pregnant.

Orlistat can interact with other drugs and shouldn’t be taken if you have underlying health issues.

Orlistat can cause stomach issues including loose, greasy stools, especially when combined with a high fat diet.

2. CLA

What does it do? Conjugated linoleic acid (CLA) is a fatty acid which is widely advertised as a weight loss aid.

Does it work? CLA shot to fame in a large part due to a study carried out on mice which produced surprising results. One group of mice were fed a CLA supplemented diet and compared to the control they went on to develop 14% more lean mass and 60% less body fat3!

As you may expect, such results in humans would be jaw dropping. Unfortunately, most studies carried out on humans have proved unconvincing. Some studies show some level of weight loss from CLA use4, while others show no weight loss benefit when taking CLA5.

Are there side effects? When taking the recommended doses you’ll unlikely notice much in the way of side effects from supplementing with CLA. However, mild side effects such as diarrhea, stomach upsets and fatigue are possible.

3. Green Tea Extract

What does it do? Green tea (including green tea extract) is packed with powerful antioxidants which can boost health and well-being. It also contains caffeine and the catechin EGCG, both of which can aid weight loss and fat burning.

Does it work? Yes and there are numerous studies which back green tea extract as an effective fat loss aid.

Firstly, green tea has a thermogenic effect on the body and increases overall calorie expenditure by around 4% over 24 hours6. Furthermore, there appears to be an interesting synergistic effect between the caffeine and EGCG in green tea which results in greater levels of body fat being used as fuel during exercise7.

A study into the relationship between green tea consumption and fat oxidation found that those who consumed green tea extract experienced 17% greater fat oxidation during moderate intensity exercise7. This confirms green tea extract is a particularly effective pre-workout supplement for those looking to lose weight and burn greater levels of body fat.

Are there side effects? Not usually, if consumed in moderate and suggested amounts. Green tea does contain caffeine, so when taken in high doses (not recommended) you may experience side effects such as stomach upsets, headaches, irritability, poor sleep and more.

4. Glucomannan

What does it do? Glucomannan is a dietary fibre extracted from Konjac, a plant native to Asia, and is widely sold as a weight loss aid. It has an extraordinary ability to absorb up to 50 times its own weight in water and primarily promotes weight loss by reducing the feeling of hunger.

Does it work? Yes, it is an effective and proven weight loss supplement.

As mentioned, its primary benefit for those following a weight loss plan is its ability to promote the feeling of fullness despite being very low in calories. It accomplishes this by absorbing water and taking up space in the stomach.

Dosed at 2-4g per day, Glucomannan has been shown to be an effective and well tolerated weight loss aid8 and can induce significantly greater weight loss compared to dieting alone9.

To be effective it must be taken shortly before a meal.

Are there side effects? Glucomannan is well tolerated and side effects are uncommon.

To prevent Glucomannan expanding before it reaches your stomach (which would be a choking hazard) it is recommended you drink a couple glasses of water or other liquid when taking it.

Due to the possibility of Glucomannan interfering with the absorption, it would be wise to avoid taking it in the hours preceding and after you take any medicines. Speak to your GP if you’re thinking about taking Glucomannan and if it could interfere with any medicines you may be currently taking.

5. Caffeine

What does it do? Caffeine is a stimulant which, amongst other things, ramps up fat oxidation (mobilises body fat for use as fuel) and increases the metabolism.

Does it work? Caffeine appears to provide some benefit for those looking to lose weight, but ironically its abilities in this regard are most pronounced in younger people who are not obese.

200mg of caffeine has been shown to increase the metabolic rate (the rate at which you burn calories) by an average of 7% during the three hours after consumption10. To note, a significant portion of this increased metabolism appears to come from fat oxidation11 – or in other words, the body is breaking up fat stores and using them to fuel activity and exercise.

While all this may sound very promising, it’s important to note that these effects appear to diminish over time, as the person builds up a tolerance to caffeine. Regular coffee drinkers may already have a fairly high tolerance so would be unlikely to see similar results.

Caffeine may be a useful weight loss aid if taken in short “cycles”, where it is taken for a couple of weeks and then completely stopped for the following weeks to prevent a tolerance build up.

Are there side effects? People who don’t usually drink caffeinated drinks will likely have a much lower initial tolerance to caffeine and may notice increased jitteriness, nervousness, stomach upsets, sleeping problems and heightened heart rate after consumption.

When used in moderate doses caffeine is considered fairly safe, but long term use and high doses are not recommended.

So, should you buy any of them?

Putting it bluntly, any benefit you get from any weight loss supplement will pale in comparison to the results you’ll notice from following a suitable diet and exercise plan.

Orlistat is fairly effective but we would only recommend its use if you’re over-weight or obese and have consulted with your GP. We would also advise you avoid purchasing it online.

If you’re looking for that extra help, Glucomannan and green tea extract (or beverage) could prove an effective addition to your weight loss plan. The greater fullness you feel when supplementing Glucomannan will help you when following a calorie restricted diet and the green tea will help increase calorie and fat burning, as well as provide a magnitude of other health benefits.

Author's Bio: 

Author, Freelance writer