Best Metabolism Boosting Diet Pills

Last updated February 2nd 2015

With so many weight loss supplements available on the market that claim to work as metabolism boosters, it can be very difficult to work out precisely which one will be the most effective and safest.

Metabolism boosting diet pills are very popular, and in consequence there are a huge number available to buy from a range of different weight loss supplement brands. These may claim only to work as metabolism boosters, or metabolism boosting may be one of many purported functions of the product. Generally speaking, metabolism boosting products claim to work through the process of thermogenesis, and increasing the activity of cells in the body, helping them to burn more calories. Metabolism boosting is one of five key areas of weight loss targeted by diet pills; this article should help you to decide whether metabolism boosting products are best for you, and if so, which products to look for and which to avoid.

How do Metabolism Boosting Diet Pills Work?

Metabolism boosting is one of the five key areas of weight loss. Metabolism is a natural process whereby fats, proteins and carbohydrates are broken down by the body and converted into energy. It also refers to the rate at which weight is gained or lost. A network of hormones and enzymes are involved in maintaining metabolism. The resting or basal metabolic rate refers to the rate at which metabolism takes place when the body is resting; in other words, it is the minimum number of calories that the body needs in order to function effectively.

Speeding up the rate at which metabolism takes place can lead to weight loss because the body is able to break fat down more quickly and burn through it. One of the ways in which metabolism can be sped up is by doing vigorous exercise; it has been shown that the metabolic rate can remain boosted for many hours after exercise has been completed. There are many diet pills available on the market, and a number of these claim to be effective metabolism boosters. These products purport to increase the speed and activity of the cells in the body, which in turn would increase the amount of calories burnt. This is usually achieved by the process of thermogenesis, which involves increasing the internal body temperature, and so helping cells to work at their maximum capacity.

Common Ingredients in Metabolism Boosting Products

Bitter Orange

Bitter orange, or more technically Citrus aurantium, is regularly added to weight loss products as a metabolism booster. The ingredient is obtained from a plant that is native to eastern Africa and Asia, the extract of which has been used for many years in Chinese medicine as a treatment for a wide variety of conditions, some examples of these include heartburn, fungal skin infections, congestion, indigestion, nausea, and constipation. More recently it has been the subject of media hype for its potential ability to help people to lose weight, and has been added to many products as an alternative to ephedrine – a substance that has now been banned for sale in weight loss supplements in the United Kingdom. The scientific evidence for the effectiveness of bitter orange as an aid to weight loss in humans is lacking, and is certainly not definitive.

Green Tea Extract

Green tea has long been known for its array of potential health benefits, and is consumed in beverage form all over the world. The extract of the tea has also been used in Chinese medicine for many years, and due to its high antioxidant capacity, it is thought to help a wide range of conditions. For example, green tea is believed to reduce cholesterol, prevent cancer, fight cardiovascular disease, and prevent Alzheimer’s disease. The ingredient can also now be found in a huge number of weight loss supplements available on the market because of its apparent potential to help to boost the metabolism. Again, the scientific evidence for this capability is debatable, and more work needs to be done.


Chromium, or chromium picolinate, is a trace mineral that is naturally found in the human body, but is also present in a number of foods such as cheese, nuts, and grains. The mineral has a role in the maintenance of blood sugar levels, working alongside insulin. The mineral is essential for humans, but is only needed in very small amounts. Chromium can be found in medications used to treat all forms of diabetes, high blood sugar, depression, polycystic ovary syndrome, and high cholesterol. It is also found in weight loss supplements because it is thought to help increase muscle mass and reduce body fat. The scientific evidence for this is however uncertain.


Caffeine, or caffeine anhydrous as it is often called in the ingredients lists of weight loss supplements, is the naturally occurring chemical that is found in products consumed by many people in their day to day lives, most notably, tea and coffee. It is a stimulant that improves mental alertness. Caffeine is also combined with painkillers in some products used to treat headaches and migraines, and is also thought to help treat asthma, gallbladder disease, ADHD, and type two diabetes. It is regularly found in weight loss supplement because it is a stimulant that is believed to work to increase the speed of the metabolism, and also suppress the appetite. There is no doubt that the substance has a stimulant effect on the human body, but its ability to work as a weight loss aid is debatable.

Garcinia Cambogia (HCA)

Garcinia cambogia is sourced from a plant that is technically called Garcinia gummi-gutta. The extract is taken from the fruit of this plant that looks like a small, green pumpkin. The fruit is regularly used in food dishes in Asia for its flavour, but has also been used in traditional medicine. It has been used in the past to treat diarrhoea and parasites, but is most well known for its potential ability to help people to lose weight. The active component of Garcinia cambogia that is believed to help to aid weight loss in humans is HCA (hydroxycitric acid). Some scientific studies have suggested that the ingredient may have potential in the treatment of obesity, whilst others have found that it has no impact.

Is there any Scientific Evidence for their Effectiveness?

Bitter Orange

There are few scientific studies that have been undertaken on the effects of bitter orange on weight loss. A first study was randomised and placebo controlled, and involved just 20 volunteers that were followed for a period of six weeks. The results of the study did not highlight any benefits of bitter orange for weight loss in humans, and did not reveal much about its safety. The experiment also used a sample size of just 20 subjects which unfortunately is not enough upon which to base any stable conclusions.

Another review study also aimed to draw conclusions from the scientific research on Citrus aurantium to date. Similarly, the conclusions of this study were that not enough studies have been performed on the ingredient to state with certainty whether or not bitter orange may be beneficial for the treatment of obesity in humans. The authors did note however that there were not many adverse effects of bitter orange mentioned in the literature that were believed to be a result of consumption of the substance, but that one constituent of bitter orange does appear to have the potential to increase cardiovascular risks and increase blood pressure.

Those few studies that were included in the literature reviews mentioned above appear to be the only clinical trials that have been performed on Citrus aurantium and its potential ability to aid weight loss. There are however a small selection of case studies available that document serious side effects that appear to be associated with the ingredient. For example, one case discusses the experience of a patient who contracted ischemic colitis, apparently as a result of the consumption of bitter orange. Ischemic colitis is a condition that involves the inflammation of the large intestine due to restricted blood flow to the area. The authors state that this patient developed the condition one week following the consumption of a diet pill containing bitter orange, and that when they stopped taking the weight loss supplement, the condition immediately began to improve, and the symptoms stopped. It is mentioned in the study that there were no other factors in the patient’s health or life history that could have been the cause of this condition. In consequence, it was deduced that the onset of ischemic colitis was highly likely to be the result of the consumption of bitter orange, and so it is something that should be considered in more studies.

Another case study is available here. In this case, the consumption of bitter orange appears to be associated with the contraction of lateral wall myocardial infarction (more commonly known as heart attack). This study describes a woman of 55 years of age who has been taking a weight loss supplement that contained bitter orange for one year before she entered a hospital having suffered a heart attack. The patient did not have any history of cardiovascular problems and she did not smoke; there did not appear to be any factors in her lifestyle that would have caused the lesion in her coronary artery. The authors concluded that the heart attack was most likely the result of bitter orange consumption, and although it is possible that it was caused by something else, there have been other similar reported cases.

Overall, the scientific evidence supporting the effectiveness of bitter orange as a weight loss supplement is lacking, and perhaps more importantly, there appears to be mounting evidence that the substance could cause severe side effects that could even result in death. It may be best therefore to avoid metabolism boosting diet pills that contain this ingredient, particularly if you have any pre-existing heath conditions.

Green Tea Extract

Green tea is one ingredient regularly found in metabolism boosting weight loss supplements that has been the subject of a significant amount of clinical trials. One such trial can be found here. This experiment was undertaken to test the effectiveness of green tea on weight maintenance following a period of weight loss. The study involved a total of 104 overweight and moderately obese male and female volunteers. These subjects were allocated to either a treatment or a control group following four weeks on a very low calorie diet. This period was followed by a weight maintenance period of 13 weeks, during which time the subjects were given either green tea or a placebo daily. The results of the study suggested that body weight regain was not significantly different between the two groups, but interestingly, those individuals in the green tea group who habitually consumed lots of caffeine appeared to regain more weight that those with a low habitual caffeine consumption.

Another study reports a study that was undertaken by Dulloo and colleagues to determine whether or not green tea has an effect on body weight and energy expenditure. The results of this experiment suggest that the consumption of green tea extract and green tea polyphenols combined with caffeine resulted in a higher energy expenditure and fat oxidation in healthy, young, male subjects. This effect appeared to be due to the green tea rather than the caffeine because a control group was used that consumed only caffeine and this group saw no significant difference in energy expenditure. It was therefore concluded that green tea polyphenols, and particularly EGCG may be able to increase thermogenesis and fat oxidation in human subjects.

A final clinical trial was performed on mouse subjects. The study was performed to test the effects of EGCG in subjects with high fat induced obesity, symptoms of metabolic syndrome, and on fatty liver. For this trial all of the mice were fed a diet high in fat, and those in the treatment group were also given 3.2g of EGCG per kg of diet, whilst those in the control group were given a placebo. The trial continued for a period of 16 weeks. Results of this study indicated that EGCG caused a reduction in body weight gain, percent body fat, and visceral fat weight in the mice that were consuming EGCG when compared to those in the control group. It was also mentioned that EGCG attenuated insulin resistance, liver lipid accumulation, and plasma cholesterol. It was thus concluded that EGCG could be a useful treatment for obesity, and may help to prevent the development of obesity, fatty liver, and metabolic syndrome. Results from studies on small mammals are not directly transferable to human subjects, but they may indicate the potential of a substance.

A useful meta-analysis of studies on the effects of green tea on weight loss and weight maintenance can be found here. A total of 11 English written papers are included in this analysis that researched the impacts on green tea on varying subjects with different caffeine intakes. The authors of the paper concluded that the catechins in green teas did appear to have a significant impact on decreasing body weight and maintaining body weight following a period of weight loss. It was not clear whether or not caffeine intake had an impact on these results, but overall, a catechin or EGCG and caffeine mixture does seem to have a small positive impact on weight loss and weight maintenance in humans.

Overall, the scientific studies of the effects of green tea on weight loss have provided positive results, although the impact is usually only small. Despite this, green tea may still prove to be useful in the treatment of obesity in humans when consumed alongside a healthy diet and regular exercise. Importantly, very few side effects have also been reported for the consumption of green tea; although there will always be some potential side effects, green tea appears to be relatively safe when compared to some of the other ingredients commonly found in weight loss supplements.


Chromium has also been the subject of a large number of scientific studies for its potential ability to aid weight loss. A pilot study assessed the ability of chromium picolinate supplementation alone and with nutritional education, to aid weight loss. 80 healthy, but overweight adults were involved in this randomised, double blind, placebo controlled study. These volunteers were split in to two groups, one of which consumed 1000μg of chromium per day, and the other a placebo, for a period of 24 weeks. After 12 weeks, subjects in both groups were given nutritional education. The results of this study suggested that chromium supplementation alone, or when combined with nutritional education, had no significant impact on weight loss.

Another study studied the use of chromium in obese subjects that also performed significant physical exercise. The subjects of this study were Navy personnel who had more body fat than the Navy’s standards. 95 volunteers completed the study that continued for a period of 16 weeks. The methods were double blind and placebo controlled; subjects were split in to two groups, individuals in one received 400 micrograms of chromium, whilst those in the other group received a placebo to consume once a day. The results suggested that the consumption of chromium picolinate did not have a significant impact on body fat reduction when taken alongside regular exercise.

A paper reports a study that looked in to the effects of chromium supplementation in individuals who suffer with type 2 diabetes. The study involved 37 subjects all of whom had type 2 diabetes and double blind, placebo controlled methods were used to test the effects of chromium on weight and insulin sensitivity. Volunteers were split in to two groups, individuals in one group were given sulfonylurea and a placebo, and those in the other group were given sulfonylurea and 1000μg of chromium picolinate for a period of six months. The subjects who were consuming the placebo were found to have a much greater increase in body weight, percent body fat, and abdominal fat, when compared to those in the treatment group. Subjects in the treatment group also had improved insulin sensitivity and free fatty acid levels.

A meta-analysis was performed in 2003 to review the published studies on the impact of chromium on weight loss. An in depth literature review was performed and only randomised, double blind, placebo controlled studies were included. A total of 10 studies fitted the inclusion criteria, and the data from these were used to perform statistical analyses. The results indicated that chromium had a significant effect at reducing body weight, however it was added that this result was largely dependent on one of the studies that had particularly positive results obtained from a large sample size. It was thus concluded that chromium may have a small beneficial effect as a weight loss supplement, but that more studies need to be performed to confirm this.

The results of scientific studies on chromium picolinate seem to be rather varied, and altogether indicate that the substance may have a small impact on body weight in some people, but that this impact will not be seen in everybody. More studies certainly need to be performed on the substance to confirm these rather contradictory results. The ingredient does however appear to have beneficial effects for sufferers of type 2 diabetes, and might have significant potential in this area.


Considering the amount of weight loss products that contain caffeine, and the amount of websites that claim that the ingredient helps people to lose weight, there are actually very few scientific studies on the impact of caffeine on weight loss. Only one can be found that specifically studies the effect of caffeine on weight loss. The study tested the associations between basal metabolic rate, thermogenic responses, and caffeine intake in obese women, and whether or not these differences have an impact on weight. 136 obese female volunteers were used, with 10 lean age-matched control subjects. Volunteers consumed a low energy diet and performed regular exercise for a period of two months. The conclusions stated that there was no difference between the basal metabolic rate and thermogenic responses to caffeine in obese and lean women.

Another paper discusses a study of caffeine and green tea, and their collective impact on weight loss and weight maintenance. This study involved 76 overweight and moderately obese volunteers who were given a low energy diet for four weeks before the trial began. The trial then took place for three months of weight maintenance, during which time the subjects were split in to two groups, one of which consumed a mixture of 270mg of EGCG and 150mg of caffeine daily, and the other a placebo. It was concluded that a high caffeine intake has an impact on weight loss and increases the processes of thermogenesis and fat oxidation in the body. Benefits of caffeine for weight maintenance however only seemed to be present for those who habitually consumed low amounts of caffeine.

One last clinical trial tested the impact of weight change on the relationship between tea and coffee consumption, and the risk of contracting diabetes. This study involved a total of 7006 volunteers – a very large sample size. The subjects were all aged between 32 and 88, and were from the ‘First National Health and Nutrition Examination Survey Epidemiologic Follow Up Study’. The authors of this paper concluded that those who had a higher habitual caffeine intake in the form of ground tea and regular coffee had a reduced risk of getting diabetes. The study also highlighted however, that this reduced risk was only the case for people who were under the age of 60 and had previously lost weight. Of course this is a rather specific group of people, but the information could still be useful for the treatment of some obese adults.

Garcinia Cambogia (HCA)

A number of studies on the impact of Garcinia cambogia and its main component, hydroxycitric acid (HCA), on weight loss can be found in the literature on small mammals and human subjects. One study on rats investigated the effects of HCA on body fat accumulation in obese subjects. The rats were split in to groups, each of which were fed differing levels of HCA (0, 10, 51, 102, and 154 mmol/ kg diet) for 92 or 93 days. The results suggested that rats consuming the highest dose of HCA had a suppressed fat accumulation when compared to the other groups. The authors also found however, that those consuming 102mmol HCA/ kg diet and above suffered from testicular atrophy and toxicity, and those consuming 51mmol HCA/ kg did not have these effects.

This study was also performed on rat subjects. Here, the long term impact of HCA on food intake, meal patterns, body weight regain, and energy conversion ratio were considered. The subjects were fed a diet containing either 1% fat or 12% fat, both of which were supplemented with 3% HCA following 10 days of dieting. The results suggested that this HCA consumption helped to reduce body weight regain and reduced the energy conversion ratio. Those who consumed the 12% fat diet also saw long term suppression in food consumption. Overall, the beneficial effect of HCA on body weight regain for three weeks seems to be independent of dietary fat content, but the fat content did appear to impact the long term suppressive effect of HCA.

study experimented with the impacts of HCA alone or when combined with niacin-bound chromium (NBC) on weight loss in moderately obese human subjects. This trial was randomised, double blind, and placebo controlled, and was performed using 60 subjects. The subjects were allocated to one of three groups, the first was given 4667mg HCA, the second was given a combination of 4667mg HCA, 4mg NBC, and 400mg GSE, and the thirs was given a placebo. These were consumed daily before meals for eight weeks, whilst the subjects consumed a 2000 calorie diet and undertook regular walking. The results indicated that the consumption of HCA alone helps humans to reduce body weight, and that this effect is even higher with the consumption of NBC and GSE.

Another study on humans produced less positive results. This study aimed to investigate the effects of HCA for body weight in overweight human subjects. The trial was randomised, double blind, and placebo controlled, and continued for a period of twelve weeks. A total of 135 subjects were all prescribed a high fibre, low calorie diet, and were split in to either a group given 1500mg HCA per day or a placebo, and 84 of these subjects completed the trial. The authors found that there was no statistically significant difference between the weight lost by people in the treatment group or those in the control group.

Overall the results of these studies on Garcinia cambogia and HCA do seem to provide results indicative of a potential for the substance to aid weight loss. The magnitude of the effect is certainly not large, but studies (only a selection of which is described here) do suggest that it could help people to achieve their weight loss goals. Gastrointestinal side effects were recorded in several studies, but none too severe in those studies on human subjects.

Side Effects of Metabolism Boosting Products

As with all weight loss products, there are bound to be some potential side effects associated with  metabolism boosting weight loss supplements, however exactly what these effects will be and how severe they may be will depend upon the precise product that you take, and its individual ingredients. Here a selection of common side effects can be provided but be sure to research the side effects of the exact ingredients in the product that you are considering before purchasing it. The most common side effects of metabolism boosting weight loss supplements tend to be associated with the gastro-intestinal tract. Examples include gastro-intestinal discomfort, stomach cramps, diarrhoea, loose stools, nausea, vomiting, and flatulence. Irritability, jitteriness, inability to sleep, and anxiety are also possible side effects.

More serious side effects have however been identified in the past relating to some specific ingredients, particularly stimulants such as caffeine, and bitter orange. These include increased heart rate, increased blood pressure, and increased risk of cardiovascular problems such as heart attack. Some have also been related to liver and kidney problems. For this reason it is recommended that you consult a doctor before consuming any weight loss supplements, and check the side effects of each individual ingredient.

Who Shouldn’t Taking Metabolism Boosting Diet Pills?

It is recommended that people who are under the age of 18, pregnant or lactating do not take metabolism boosting supplements. People who have any pre-existing medical conditions should contact a doctor before consuming a weight loss supplement, particularly if these are related to the cardiovascular or digestive systems, or the liver or kidneys. Also be aware if you have any allergies or are taking any form of medication. Some ingredients can interact with certain medications; ask your doctor if you are unsure.

Are Metabolism Boosters Right for You?

A slow metabolism results in the body being less effective at burning calories, which can result in excess calories stored as fat, which can lead to weight gain. When metabolism is fast, calories are burned off effectively, allowing you to lose weight effectively. Two people who eat the exact same foods might put on different amounts of weight because they one has a faster metabolism than the other.

There are a lot of different factors that influence a person’s individual rate. A person’s genes can influence their rate, as can their weight; it has been shown that people who weigh more actually have a quicker metabolic rate because their body has to worker a bit harder to properly sustain itself. Because overweight people have a higher metabolic rate, they will find it easy to start losing weight because, even if they reduce their calorie intake, the metabolic rate is still quite high. As more weight is lost, the body requires fewer calories in order to sustain itself, so the metabolic rate decreases.

A person’s gender and their age can also affect their metabolic rate; men tend to have a quicker metabolic rate than women because they tend to have more muscle and less body fat. The metabolic rate usually slows down as people get older because the amount of muscle decreases and fat comprises a greater amount of the total body weight.

The basal metabolic rate contributes to about 60-75% of the calories an average person burns on a typical day. Two other factors contribute to calories burned up each day: physical activity and the processing of food. Physical activity, and also any exercise, can account for a significant number of calories burned, though this is very flexible as people do different amounts of physical activity. Processing food accounts for roughly 10% of the calories burned on a typical day. Food has to be digested, absorbed into the body, transported and eventually stored; all of these processes require calories to be burned, though the total amount needed does not change much from day to day.

So are metabolism boosting weight loss supplements the right choice for you? It is important to remember that metabolism boosting is only one of five key areas of weight loss targeted by weight loss supplements, and different types of supplement will work best for different types of people. You may find metabolism boosters useful if you are over the age of 60, as by this time your metabolism is likely to have slowed down naturally with age. That being said, metabolism boosters are known to have a number of potential side effects, and the ingredients in some metabolism boosting products could be dangerous for people with any pre-existing medical conditions.

For information on the side effects and a list of people who should not take metabolism boosting products, see the sections above. If however you are healthy and do not suffer from conditions relating to, for example, the cardiovascular system, then you may wish to try metabolism boosting weight loss supplements. The amount of exercise that you undertake also impacts the speed of your metabolism, and people who are able to undertake a significant amount of exercise are likely to get the most benefits from these products.

Overall, whilst the products may have a slight effect on other people, these products are generally recommended for people whose metabolism has naturally slowed (i.e. people over the age of around 60), or people who are particularly active. If you are young and healthy but do not perform any regular exercise, then metabolism boosting products may not have a significant effect on your weight loss regime. Similarly, if you are elderly, but suffer from medical conditions, then it may be best to consider a different form of weight loss supplement.

How to Choose a Good Metabolism Boosting Product

With so many different weight loss products claiming to work as metabolism boosters available on the market, it can be very difficult to work out which one is likely to produce the best results for you. Here some of the factors that should be taken in to consideration before purchasing a metabolism boosting product will be discussed. Any good metabolism booster should be effective, safe, good value for money, available from a reliable retailer, and it should have ingredients of a good quality. Diet pills that work as metabolism boosters often function as a fat burner / binder as well, and their ability to boost metabolism is usually a secondary effect.

Before shelling out the money, you want to know that a product has the potential to work. There are ways of checking to see whether there is any scientific evidence supporting a product, and seeing whether it has worked for other people, but bear in mind that even if a product has been shown to work for some people, this does not mean that it will work well for you, just that there is a chance it might. Firstly it is recommended that you search for the particular products that you are considering on Healthy Compare using the search feature. This should reveal an article on the product which will review the product and any scientific evidence that is available to back up its weight loss claims. It will also go in to detail about each of the ingredients in the product.

Alternatively, you can look for scientific studies yourself using a search engine. It is also important to search for independent customer reviews of the product. Again, a summary of these will be provided in the Healthy Compare articles, but if you want to read a wide variety for yourself, Amazon is often a good place to start. Do not trust reviews and testimonials provided on the product website itself – there is a possibility that these will be biased, and so won’t be a fair spread of reviews on the product. As well as giving you an idea of whom the product works for and whom it doesn’t, customer reviews should also give details about other factors, such as side effects.

Also use the product reviews on Healthy Compare to ensure that the ingredients are safe, and that the product doesn’t contain any dangerous or banned substances. To avoid purchasing products that may not be safe, it is recommended that you buy from well known retailers. Preferentially, the product should be brought from a renowned high street store, but it should also be safe to buy from popular, well known retailers online. If you are unsure whether the retailer you are purchasing from is safe, look for customer reviews of the company. Also consider their website, for example, are full contact details provided? Where is the company based? Is there any information on the history and ethics of the company? Do they sell any other products? And are these found in other well known stores?

The same must be said about the manufacturer of the product. The product will not always be made by the company selling it, so make sure that there is plenty of information available about the manufacturing company, and check out the manufacturer website. Again, look for things like contact details and perhaps more importantly for the manufacturer, look for safety practices, regulations, and any awards the company or products have. Finally, be aware of scams online; these are particularly common in the weight loss supplement market. Be particularly wary of any websites offering a ‘free trial’, especially if you have to enter your bank details before being allowed this ‘free trial’. For more information on diet pill scams and how to avoid them, see our article here.

What are the Alternatives to Metabolism Boosters?

Weight loss supplements can target one or more of four different areas of weight loss, and these may be coupled with a diet plan. The main areas that diet pills target are metabolism boosting, fat burning or binding, carbohydrate blocking, or appetite suppressing. These may also be accompanied with a diet plan tailored to suit the action of the weight loss supplement. Fat burning diet pills usually work in a similar way as metabolism boosters. Generally speaking they induce the process of thermogenesis, meaning that the internal body temperature rises and the action of the enzymes involved in the breakdown of fat molecules is optimised.

Fat binders work in a slightly different way; these substances claim to bind to fat molecules in the digestive system, making them too large to be absorbed by the body through the small intestine lining. Similarly, carbohydrate blockers supposedly work by preventing the action of the enzymes involved in the breakdown of carbohydrates, meaning that the carbohydrate molecules remain too large to pass from the digestive system in to the body. When taking fat binders or carbohydrate blockers, the fat or carbohydrate molecules respectively thus pass through the gastro-intestinal system without being absorbed and are excreted naturally in the stool.

Finally there are appetite suppressing products; these work in one of two ways. Most of these products claim to alter the concentrations of certain neurotransmitters in the body, such as serotonin, that are involved in controlling the appetite. By doing this, they should make the body feel full, reducing cravings for food. Alternatively, some appetite suppressants claim to work by filling up the stomach with a gel-like substance that expands in the stomach once it has been ingested. This substance is indigestible, but makes the stomach feel full. It is then passed out naturally in the stool.

Each of these products is likely to suit a different person, and whilst some products may only target one area of weight loss, others claim to work in each of the five different ways. To help you to work out which type of product might be best for you, see our article on the best diet pills by goal and by user here.