Are Fat Burning Pills Safe?

fat burning pills

Short Answer: No, not really.

Fat reducing pills are very popular in both the bodybuilding world and among people trying to lose weight.

The Internet has made such supplements and medicines more accessible to people that would not normally think to buy them, and few people question if they are effective or safe, before buying online.

There are several types of diet pill on the market now. There are fat blockers which actively reduce fats from the foods you eat from being absorbed through the wall of the digestive tract, reducing the amount of energy (calories) you take in. Similarly there is a drug which blocks the uptake of carbohydrate. Neither of these pills are really safe in the long term and both have some side effects which are not very pleasant. Some drugs are positively unsafe, DNP is an example. DNP kills and is illegal, but people are still taking it to aid weight loss.

Fat burning pills work a little differently in that they are designed to increase metabolism that more fat can be lost. Most often fat burning pills are used by bodybuilders prior to competitions when “cutting” is most important. How the pills work to increase metabolism varies, but most contain a chemical concoction of caffeine, guarana, green tea and other ingredients which have been shown to possibly aid an increase in fat burning.

Are Fat Reducing Pills Safe?

Although losing fat can be simpler and easier with the correct advice and nutritional products, it is absolutely essential that fat burning pills are only taken by people that are working out intensively on a regular basis. The pills should never be taken by people that are looking for an easy way to lose some weight. At best they just will not work, and at worse they could lead to side effects and ill health.

What Is A Fat Burner?

Most people know that to lose weight, you need to eat less and exercise more. The problem is that dieting can be a physical and mental torture! A fat burner helps you move towards your weight management goals, as part of your diet and training regime.

Do Fat Burning Pills Work?

OK, so they may not be totally safe, but do they actually work as claimed? To answer that, we first, we need to look at what they are.

A fat burner helps you to mobilize and burn fat when used in conjunction with a sensible diet and exercise program. What this means is that the pills help encourage your body to break down more fat tissue for energy. However, the science is not conclusive – there is no solid evidence that they are effective, most of the claims are from individuals that believe they have helped.

For example, Maximuscle’s best selling fat-burner Thermobol contains ingredients that research shows could increase fat loss. This will help you feel more in control when restricting calories, helping to support your weight management goals.

Should You Use A Fat Burner?

If you’re training hard and still finding it difficult to lose weight, or you’re frustrated by the fact that the weight is not coming off quickly enough, a fat burner could help you reach your weight management goals more quickly.

One of the features of a fat burner is that it raises your psychological and nervous energy levels – you can become highly strung. This is designed so that you exercise with a greater intensity and therefore burn more energy.

This is the thermogenesis effect – you get hotter and work harder to burn more. It is argued that positive thinking and mental preparation before exercise can have a similar effect. In fact, much of sports and athletics coaching involves working on the psychological aspect of training to reach peak performance.

However, some research has shown that “bioactive components may support weight maintenance after a hypocaloric diet” (Belza, 2006).

Likewise, research into the effects of a green tea supplement shows it “enhances exercise-induced changes in abdominal fat” (Maki et al, 2009), i.e. you must exercise for it to be effective.

Are Fat Reducing Pills Safe?

There are many risks associated with taking these kinds of medications. Fat blockers in particular have some negative side effects, including stomach aches, diarrhea, and a tendency to interfere with other medications, notably birth control and estrogen supplements. They can also encourage undernourishment as they often block the absorption of lots of fat-soluble vitamins.

Some of these medicines are high in substances like caffeine, which can have a negative effect on the heart. These medications also don’t help slimmer to re-learn appropriate eating habits.

If you are looking to lose some extra fat, and are exercising on a regular basis, then fat burning pills such Maximuscle’s Thermobol can help to speed up metabolism to burn fat. Some products such as CLA-1000 also help to break down fat.

Typical Side Effects of Fat Burning Supplements

  • Caffeine – anxiety, sleep disruption, confusion, headaches, seeing flashes, tinnitus, mania and psychosis (rare and with very high doses).
  • Guarana – insomnia, headaches, nervousness, anxiety, heart palpitations and high blood pressure.
  • Green Tea Extract – restlessness and insomnia
  • CLA (Conjugated Linoleic Acid) – linked to increased risk factors for heart disease
  • Chromium – anemia, memory loss and DNA damage linked with chromium picolinate.
  • Chitosan – gas, bloating and diarrhea. Malnutrition possible due to blocking of fat soluble vitamins.
  • Ephedrine– hypertension, heart palpitations, acne, anorexia, urinary tract problems, confusion, insomnia, delusions, paranoia, panic attacks, headaches and dizziness, plus many more. The worse know side effects recorded have been “stroke, heart attack, and death” (FDA, 2004). Seek medical advice before going near this stuff.

Really it is for the consumer to weigh up the risks and benefits and decide if fat reducing pills are safe for them. There is no sure answer. The best answer is to adopt a healthy diet and do plenty of quality exercise. If you do decide to experiment with a fat burning supplement it is wise to keep a diary and note any unusual feelings or behavior. Increased aggression, anxiety, sleeplessness or paranoia and confusion could all indicate a problematic side effect of one of the ingredients and stopping the supplements immediately is the only recommended course of action.

Following a well structured weight loss system that emphasis both diet and exercise is the best way for most people to lose weight. However, many people intent on looking for the quicker, easier option, and if you are working out hard, then a fat burner may work well for you.

Diet Pills Kill Woman – The Dangers of Too Much Caffeine


This is not actually breaking news and we are not aware of any recent deaths. However, on researching the relationship of caffeine and health I came across a report from the journal of Veterinary & Human Toxicology that reported a death due to caffeine overdose. Although deaths from excess caffeine are rare, they do happen, and with more products flooding the market containing caffeine, these deaths are likely to continue. This gives rise to a larger question, are diet pills really safe? It is a subject that we have covered already, however, the risk of death from caffeine overdose was not considered.

A 22 year-old female was rush to accident and emergency after suffering a heart attack. Her heart attack came on after consuming too many diet pills that she had purchased online. These pills were of a thermogenic nature, designed to increase metabolism by raising heart rate. For this woman the result triggered a heart attack that killed her.

Cause of Death: Caffeine

A post-mortem examination revealed that she had a caffeine level of 1,560 micrograms/ml in her blood. The lethal limit is considered to be 100 micrograms/ml. Her caffeine levels were 15 times higher than the fatal level. How did she manage to accomplish this? No other substances were found in her blood and her death was attributed to acute caffeine toxicity.

Thermogenic Diet Pills and Fat Burners

Thermogenic diet pills are popular for one reason – they are currently legal to be sold over the counter, without prescription. The only diet pills to really work, such as fat blockers and carb blockers, have not passed testing or have had to be withdrawn from the market due to serious side effects. The thermogenic ones remain because so far they have not resulted in many fatalities.

The idea really is that by taking a thermogenic diet pill you increase your heart rate and metabolism to encourage you to exercise. Studies have found that when you consume caffeine you will workout with a greater intensity. Many athletes and bodybuilders drink black coffee in the morning before their cardio sessions for this reason. Although it is not known what happened in the case reported in Veterinary & Human Toxicology, there is a real risk that not exercising could be the cause of the highly elevated levels.

How Much Caffeine is Safe?

Over-the-counter caffeine tablets generally contain up to 100 mg of caffeine. In 2004 Sweden put a restriction on caffeine tablets, limiting the number that could be bought without prescription to just 30 at a time. This was in response to deliberate caffeine overdosing.

Overdoses of tablets containing caffeine can be fatal, suicides as well as accidents occur.” (Thelander et al, 2010).

The study by Thelander reported the case of a 21-year-old woman who had taken 10 grams of caffeine (100 tablets). She called the ambulance afterwards and was taken to hospital but no problems were seen. Just as she was leaving hospital she collapsed after developing ventricular fibrillations (irregular and inefficient heart contractions). After 30 minutes her heart was restored but she suffered several more attacks afterwards. Doctors eventually stabilized her, but after being in hospital for 13 days in intensive care she deteriorated and died. The caffeine overdose essentially destroyed her heart, or her ability (the brain’s subconscious influence) to control her heart.

The same study looked at the toxicological results of 20 deaths attributed to caffeine overdose and in 2 of the cases ephedrine was found in the blood. Ephedrine is another chemical used in fat burners and stimulants designed to help people to lose weight.

How Much Caffeine in Over-the-Counter Pills?

Here are a selection of “fat burners” chosen at random by searching for “far burners” in Google Shopping results on 21st November 2011. Caffeine data taken from the product websites.

  • Maximuscle Thermobol, 90 capsules. 153 mg caffeine each.
  • Twinlab Ripped Fuel Extreme, 60 capsules, 220 mg caffeine each.
  • Nutrex 1158 Nurtex Research Fat Burner LiPo, 120 capsules – 200 mg Caffeine Anhydrous USP each.
  • Forza T5 Super Strength Fat Burners – 60 caps, 200 mg Caffeine each.

As you can see, each of these contains more capsules than the Swedish government allow to be sold on health grounds. Just 50 of the Nutrex capsules will provide 10000 mg (10 gram) of caffeine, the same amount that killed the healthy woman who Thelander and co wrote about in 2010.

Although the advice is to take one fat burner / thermogenic pill per day, some people do not read the labels and think that taking more will result in more fat burning. This is why care has to be taken as accidental overdoses do occur, and people tend to think that it is not possible to overdose on over-the-counter medicine. It is highly unlikely that anyone would take 50 fat burners in one go, however, currently the safe lower limit is not known.

How Effective is Caffeine?

Caffeine is certainly a stimulant, but does it really improve performance? Graham and Spriet (1991) examined the effect of caffeine on endurance athletes and concluded that neither cyclists nor runners saw any improvements in respiratory exchange ratio (used to measure fat burning) or plasma free fatty acid data (an indicator of total fat oxidation / fat burning) at rest or during exercise.

Some studies, such as the one by Namdar and colleagues in 2006 showed that caffeine actually reduces blood flow to the heart and may impair athletic performance.  As little as 2 cups of coffee reduces exercise-induced myocardial flow reserve at normoxia. Myocardial flow reserve is the rate at which blood can flow through the heart, and so impacts on the amount of oxygen that can be delivered to the muscles during exercise.

Caffeine has been shown to help muscles recover after exercise, but it is also responsible for increasing cholesterol levels.

So, care must be taken if you are considering taking fat burners that contain caffeine, caffeine based energy drinks or lots of coffee. Although coffee does seem to have some advantages and positive effects on health and fitness, there are also some serious side effects of having too much caffeine.

So, are there safe fat burning supplements? While none are dangerous as such, none can be considered totally “safe”, as all have side effects. Caffeine overdose is possible, as mentioned above. People with heart conditions or high blood pressure should avoid fat burning pills.

For most people reading this, and that includes you, a combination of exercise and healthy eating is all that is required.

References and Further information into fat burning products

  • Fat pills give modest weight loss” BBC News, 16 November 2007. Accessed Oct. 2011.
  • Weight Loss Products and Programs” by J. Anderson, L.Young, and J.Roach. 2008. Colorado State University. Accessed Oct. 2011.
  • “Body fat loss achieved by stimulation of thermogenesis by a combination of bioactive food ingredients: a placebo-controlled, double-blind 8-week intervention in obese subjects” by A Belza, E Frandsen and J Kondrup. International Journal of Obesity (2007) 31, 121–130. doi:10.1038/sj.ijo.0803351. Abstract:
  • “Effects of Citrus aurantium extract, caffeine, and St. John’s Wort on body fat loss, lipid levels, and mood states in overweight healthy adults” by Carlon M. Colker, Douglas S. Kaiman, Georgeann C. Torina, Theresa Perlis, Chris Street. Current Therapeutic Research, Volume 60, Issue 3, March 1999, Pages 145-153.
  • “Thermogenic Effect from Nutritionally Enriched Coffee Consumption” by Jay R Hoffman, Jie Kang, Nicholas A Ratamess, Peter F Jennings, Gerald Mangine and Avery D Faigenbaum. Journal of the International Society of Sports Nutrition 2006, 3:35-41 doi:10.1186/1550-2783-3-1-35. Full; article:
  • “Green Tea Catechin Consumption Enhances Exercise-Induced Abdominal Fat Loss in Overweight and Obese Adults” by Kevin C. Maki, Matthew S. Reeves, Mildred Farmer, Koichi Yasunaga, Noboru Matsuo, Yoshihisa Katsuragi, Masanori Komikado, Ichiro Tokimitsu, Donna Wilder, Franz Jones, Jeffrey B. Blumberg, and Yolanda Cartwright. J. Nutr. February 2009 vol. 139 no. 2 264-270. Full article:
  • “Federal Register Final Rule – FR69 6787 Final Rule Declaring Dietary Supplements Containing Ephedrine Alkaloids Adulterated Because They Present an Unreasonable Risk February 11, 2004” FDA Online publication. Accessed October 2011.
  • Anti-obesity Drug Suspended Due to Psychiatric Risks –
  • “Massive caffeine ingestion resulting in death” by Mrvos RM, Reilly PE, Dean BS, Krenzelok EP. Vet Hum Toxicol. 1989 Dec;31(6):571-2. Abstract:
  • “Caffeine fatalities – Do sales restrictions prevent intentional intoxications?” by Gunilla Thelander, Anna Kristina Jönsson, Mark Personne, Gunilla Sjölin Forsberg, Kristina Magnusson Lundqvist And Johan Ahlner. Clinical Toxicology (2010) 48, 354–358. Abstract:
  • “Acute caffeine ingestion fatalities: management issues” by Shum S, Seale C, Hathaway D, Chucovich V, Beard D. Vet Hum Toxicol. 1997 Aug;39(4):228-30.
  • “Performance and metabolic responses to a high caffeine dose during prolonged exercise” by T. E. Graham and L. L. Spriet. Journal of Applied Physiology. December 1991 vol. 71 no. 62292-2298. Abstract:
  • “Caffeine Decreases Exercise-Induced Myocardial Flow Reserve” by Mehdi Namdar, Pascal Koepfli, Renate Grathwohl, Patrick T. Siegrist, Michael Klainguti, Tiziano Schepis, Raphael Delaloye, Christophe A. Wyss, Samuel P. Fleischmann, Oliver Gaemperli and Philipp A. Kaufmann. Journal of American College of Cardiology (JACC), 2006; 47:405-410, doi:10.1016/j.jacc.2005.08.064.

163 Comments on “Are Fat Burning Pills Safe?”

  1. MotleyHealth says:

    Hi Martha, it is unlikely that the total caffeine intake will cause any lasting problems but you might feel a bit jittery, especially if you are not used to drinking coffee etc.

    Remember to cut out all bread and baked foods during the cutting process – this is probably more important than the supplements.

  2. Hy, I am 18 YEARS old and my weight is 100 give me a fat burnner to lose weight who don’t have side effect :) i am doing many exercise butt they can’t help me to lose weight.

  3. MotleyHealth says:

    H Ashly, is that 100 kg or 100 pounds? If 100 pounds then your must already be at a slim. All fat burners have unpleasant side effects.

  4. Rudresh BJ says:

    conusming 5 to 8 lipo 6 black ultra at a time , is that leads to death

  5. MotleyHealth says:

    Rudresh, just follow the advice on the instructions and read the warnings concerning side effects. The label does say ” highest potency: only one pill needed” so you are best to follow that advice if you really want to take them.

    I found this online, it is probably on the label too:

    “Directions For Lipo-6 Black Ultra Concentrate: Take 1 Black-Cap in the morning and 1 Black-Cap in the afternoon. This is an ultra concentrated formula of extreme potency. NEVER EXCEED 1 BLACK-CAP PER SERVING. NEVER TAKE MORE THAN 2 SERVINGS IN A 24-HOUR PERIOD. For maximum results consume LIPO-6 Black Ultra Concentrate at least 30 minutes prior to a meal. Do not take within 6 hours of sleep.”

    Of course, there will always be people who want to take more.

  6. I need to know if fat metaboliser is ok to use for sumone who has asthma please reply thank you

  7. MotleyHealth says:

    Hi Nabz, that is impossible to say. If there are known risks they will (or should) be listed as side effects and warnings on the label of the product that you are considering. Of course, only the known risks can be listed – the absence of a warning does not mean that there is not a health risk. Read the label and make your own choice. Consider taking a product and asking your asthma doctor about it if possible.

    Some asthma medications actually have the same chemicals as you find in some fat burners. Ephedrine is an example of this. However, it should obviously be taken under medical supervision if you are asthmatic – it has many adverse side effects, including tachycardia, cardiac arrhythmias, confusion, insomnia, headache, tremor and plenty of others.

  8. Can t5 fat burners effect fertility? I am trying to get pregnant and live a healthy ish lifestyle. I go to the gym several times a week and eat well but feel that a little extra weight loss may help. Please note that I will not use whilst pregnant or nursing but would like to use prior to conception only upon recommendation!!

  9. chetan kapoor says:

    hi i am chetan 23 years old i have beeñ using asia black 25 from 9 days and taking 1 pill before half n hour of my workout…i usually do workout 6 days a week and lost 8 kg in a month now my weight is 85 nd my trainer advice me to take 2 pills at a once beforr workout….is it safe for me to take …..i usually get asleep due to pills..nd get some times of headacke also….so plzz advice me how much should i take d dose

  10. MotleyHealth says:

    Hi Chetan, it’s your call, we cannot advise. Headaches are not a good sign though, neither is falling asleep when you do not mean to.

  11. Fat burners are not useful. Although they produce heat and burn some fat, they make me hungry and I tend to eat more food. So instead of loosing weight u gain more weight.

  12. i am using nutrex lepo 6 fat burner last one week . they suggested on lable 4 pills per day . but i sm taking 2 pills . Now i feel litle strain on heart . now i plan stop it .

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