Do Diet Pills Work?

Everybody wants a quick fix, and that is not more true than in weight loss.

The concept of fat loss is pretty simple, eat less and move more, a very simple concept and yet people still turn to magic diet pills for answers to make their dreams come true.

Body composition can be drastically changed from exercise and diet alone, you’re going to be disappointed of you skip these important step and try to go for the quick fix. It is also wise to question whether diet pill even work at all.

Fat-loss supplements are a very small part of the equation and should be seen as such, if you take a fat-loss supplement that helps you burn an additional 80 calories per day but you consume an extra 500 calories from lattes and muffins you need to re shift your focus somewhat.

Not every diet pill is the same either, some ingredients work and others aren’t worth bothering with, learn some of the common ingredients found in diet pills and may actually help you in your fat-loss efforts.


Claims: Burn more fat, increases metabolism, melts away fat.

Common Ingredients: Caffeine, Green tea extract, Green coffee extract, Guarana.

How They Work

People often turn to stimulants looking for a little help with weight-loss. This may help increase calorie burn and give a burst of energy during workouts.

Caffeine is the world’s most well-known stimulant so is found in almost every type of diet pill. Research has shown it’s ability to increase fat-burning rates and allowing your body to use more fat, rather than carbs, it also has a short-term effect on resting metabolism.

The ergogenic effect of caffeine is strongly linked to habitual caffeine consumption, going through many pots of coffee everyday may not see you with any extra benefit at all.

Green tea extract has also shown to help with weight loss by giving an increase in fat oxidation and metabolism. Be sure to take notice of the amount of epigallocatechin gallate (EPCG) that is in the product. EGCG is an active antioxidant in green tea and is responsible for its fat burning properties.

Another popular ingredient, green coffee extract comes from coffee beans that have not been roasted. These type of beans contain higher levels of chlorogenic acid when compared to normal roasted coffee beans and it is also believed that they aid weight loss by preventing carbohydrate uptake from the intestines after a meal. It is pretty safe to use in healthy individuals although its benefits don’t appear to be as potent as ingredients like caffeine and EGCG.

Guarana comes from the seeds of a fruit bearing tree and is used for its stimulant properties and it’s ability to increase fat oxidation. Guarana contains a high level of caffeine but as research has been performed on animals it is difficult to say whether guarana aids weight loss in humans.

Don’t believe all the hype you read about supplements, there isn’t many of them that do anything at all for weight loss.

Possible Side Effects

Stimulants have been known to cause a few side effects like dizziness, increased heart rate, insomnia, nausea and can make you jittery.

Recommended Dosage

200-400mg of caffeine, 600mg EGCG, 600-1500mg of green coffee extract (200mg chlorogenic acid) and 50-75 mg guarana.

Appetite Suppressants

Claims: Suppress appetite, Kill hunger pangs and also keep you feeling fuller on fewer calories.

Common Ingredients: Hoodia, yerba mate and chromium picolinate.

How They Work

Appetite suppressants are supposed to help you get rid of cravings, give you normal appetite levels and also support your weight-loss goals. As well as caffeine, there are a few other ingredients that claim to help blunt hunger signals whilst giving you better energy levels and increasing your metabolism.

Hoodia gordonii which is a small plant used by various indigenous hunter-gatherer people of southern Africa as an appetite suppressant to help them with harsh desert conditions has found its way to the weight loss market. In theory, this plant should be a miracle in any diet pill but most of hoodia’s research has been done on rats. With the unknown toxic effects and the unsupported effects on humans there is not enough data yet to support its use.

Yerba mate is yet another herbal stimulant usually found in tea and pill form, it claims to make your stomach retain food for longer so you feel fuller for longer after eating.

Chromium picolinate states it decreases appetite, burns more calories, drops body fat and boosts muscle mass. Despite promising claims blown hugely out of proportion by the media there is no evidence on its effect on body composition.

Appetite suppressants have no evidence backing up their effectiveness.

Possible Side Effects

Chromium can cause GI issues like gas, bloating and diarrhea as well as heart arrhythmias and seizures. Insomnia, irritability and headaches have also been known with chromium picolinate and yerba mate.

Recommended Dosage

Appetite suppression research is low, there is no common weight loss ingredient found in fat-burners or supplements that suppresses appetite at a given dosage without causing potential negative side effects. Additionally, yerba mate has regularly been associated with upper digestive tract cancers. Although the association is weak it is worth taking note of.


Claims: Flush fat out of the body and cleanse it of toxins.

Common Ingredients: Cascara, senna and psyllium.

How They Work

In a way, most of the fibers interact with the intestinal tract to help improve intestinal mobility and increase the frequency and quality of bowel movements. Psyllium can bind to fatty acids and cholesterol from a diet and is said to be gentler laxative than senna and cascara.

Due to laxatives’ limited effect on weight loss, it is not recommended to consume them unless you suffer with constipation and consequential intestinal discomfort or pain, it is also recommended not to take these for more than a week.

Possible Side Effects

Besides the obvious, being stuck on the loo all day, laxatives can cause dehydration and GI stress.

Suggested Dosage

1-2g of senna (standerdized to 10-30mg of active sennosides), 5g of psyllium taken 3 times a day, 325mg of cascara.

There are many, many weight loss products on the market, be careful what you take.

Other Popular Weight Loss Ingredients

Chitosan and Guar Gum

These ingredients are regularly praised for their ability to block the absorption of fats and cholesterol. Chitosan has been shown to have a little effect on fat absorption, these effects however are tiny, leaving weight loss claims unsubstantiated, possible side effects of these include an upset stomach and GI distress.

Conjugated Linoleic Acid (CLA)

Apparently, CLA helps you lose body fat and increase muscle mass. This ingredient regularly features in weight loss supplements, although long-term trial evidence (usually done in obese individuals) suggests that the effects are minimal at best. Recommended doses are 3,200 – 6,400mg daily, it is best taken with meals to avoid nausea, an upset stomach and diarrhea.

All of these other weight-loss pills can be slightly beneficial but mostly do very little ro help you.

7-Keto DHEA

This is said to boost metabolism so that you burn more calories throughout the day. Studies have been done that show 7 Keto DHEA can be an effective weight loss aid in both normal and overweight adults. 200mg has been shown to accentuate the decrease in RMR associated with caloric restriction, as well as weight loss and a decrease in body fat.

Raspberry Ketones

This comes from the obvious raspberries and shows promise of lipolysis and fatty-acid oxidation at a molecular level, however there is human data as of yet. When converting the dose from an animal level to a human, it becomes a very high dose indeed (something like 90-300mg per kg of bodyweight).

Garcinia Cambogia

This is a small fruit used in cooking and is a good source of hydroxycitric acid (HCA) which is claimed to aid weight loss, you can clear see similarities here, supplementation shows promise in animal-model research but human studies are limited with mixed weight loss results.

Some studies have shown a small benefit (3 pounds over 3 months) whilst others have shown no benefit at all. Like raspberry ketones, human daily dosage would be somewhere north of 1000mg which is substantial.


Yohimbine is stated to increase testosterone levels and help with weight loss. Yet again, research on yohimbine and weight loss is inconclusive, although doses of 0.2mg per kilo of bodyweight have shown to improve weight loss. Yohimbine works by increasing levels of adrenaline in the body, however side effects worth noting are an increased heart rate and anxiety.

Nothing can really beat a good diet and great exercise plan.

Be Wary Of ‘Proprietary Blends’

These are blends that may contain your favourite ingredient, but not knowing the exact amounts, it is pretty impossible to evaluate a product’s true potential. Ingredients are usually listed by largest relative dose to least but you get nothing other than the total dose of the blend.

This can be unsafe when you consider that proprietary blends contain stimulants like caffeine or yohimbine as consuming too much of these ingredients can have nasty side effects, contact the company and try to find out the exact doses in the blend, if they refuse then look elsewhere.

Two Ingredients To Avoid

It is always a good idea to consult your physician before consuming any of the ingredients listed above, there are two that should be considered with extreme caution. Bitter orange, which contains synephrine, an ingredient related to ephedra which can be dangerous for people with heart conditions as it tends to raise blood pressure.

Ephedra (AKA ma huang) has been FDA banned as it has been linked to some serious side effects which include heart attacks, arrhythmia, strokes, seizures and death.

There is no shortcut to quality, sustained body-composition improvements. You can take as many supplements as you want but unless you are training and eating right you are literally throwing away your money, as to whether ‘do diet pills work?’ the simple answer is that they can complement your fitness efforts but not replace them.


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