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Diet Pills: Hard Facts About Weight Loss Medication

Diet Pills: Hard Facts About Weight Loss Medication

Do Diet Pills Work?

We examined 19 of the most common weight loss drugs and supplements to find out.

We’ve said a lot about diet pills in the past. A lot of it has been negative. Of course, when a residential weight loss camp – the kind of place that focuses on getting results the hard (it's pronounced “right”) way – tells you that an alternative method is bunk, you’re likely to take it with a grain of salt. 

So today, we’re going to take a closer look at the various medications and pills out there, and give you an honest-to-goodness summary on what works, what doesn’t, and why. 

Before we get started, I should make note of a few things:

  1. Some of the weight loss drugs, pills and remedies we’ve reviewed below do offer weight loss benefits when combined with a healthy diet. Before you get too excited however, you should know that none of them will make you magically lose massive amounts of weight, particularly without any changes to your diet.
  2. I am not a licensed physician, or certified to make any medical claims about any product. The research and opinions provided here are just that – my own research and personal opinions – and as such are intended for strictly informational purposes. While I have done my best to provide well-researched and referenced data, there is always room for error – and the opinions of course, are entirely my own.
  3. If you are looking to burn off a significant amount of body fat in a short time, no supplement or pill can match the results and rewards that you'll enjoy from attending a residential weight loss program like those offered by Weight Crafters. Click here to learn more about our program.
  4. Never begin taking any medication or herbal remedy without first consulting with your doctor. The same goes for starting any kind of diet or weight loss plan. 


Non-Prescription Diet Pills

This is by far the more popular group of weight loss medications on the market. Why? Because when anyone can sell them to anyone who will buy them based on any claim the seller feels like making, that opens up the potential for huge profits in a huge market.

Some work. Some don’t. Some are sold by sketchy companies eager to send you free samples if only you’ll let them take your credit card number, while others can be picked up relatively cheaply almost anywhere. We can’t review every capsule offered out there for obvious reasons – but below is a list of the better-known names and ingredients in the industry.


Hydroxycitric Acid AKA Garcinia Cambogia / Garcinia Atroviridis (Clenbutrol, among other brands)

Even if you’ve never searched for weight loss supplements before, you likely still know the name Garcinia Cambogia. The Indonesian tropical fruit has been used as an ingredient in Indian foods for hundreds of years, but only gained international recognition as a household name when it was featured as a “miracle cure” by Dr. OZ for weight loss

The active ingredient is Hydroxycitric Acid, or HCA. It is typically obtained by grinding up the rind of the Malabar Tamarind fruit into a powder – but can be found in a number of other tropical plants as well. Studies done with Zucker rats (a strain of lab rat genetically prone to obesity) showed that large doses of HCA effectively prevented young rats from gaining as much weight as quickly as control groups. An unfortunate side-effect however, these high doses of HCA also prevented male Zucker rats’ testicles from fully developing. Human trials have been limited in scale, accuracy, and findings. 

Pros: In high enough quantities, HCA blocks a fat-producing enzyme called citrate lyase, effectively making it more difficult for the body to create additional fat. It may also increase levels of serotonin in the brain, which could lead to decreased appetite.

Cons: At the dosage levels required for significant fat reduction, it also effectively sterilizes lab rats. Cases of hepatotoxicity (chemical-driven liver damage) in humans have been reported. Research done on humans has shown little or no statistically relevant weight loss result. Even at high doses, Garcinia Cambogia has no direct effect on existing fat – it merely makes production of new fat more difficult. 

Final Thoughts: Garcinia Cambogia is a perfectly safe ingredient for your favorite curry...  But that’s the only good reason to consume it.

Extra Note about Clenbutrol: Don't mistake Clenbutrol for Clenbuterol (with an E) - the former being an herbal supplement and the latter being an illegal steroid. We're just certain the names are similar by coincidence.


Caffeine Anhydrous & Caffeine-based Supplements (PhenQ, Phen24, Hydroxycut, Dexatrim, Trimtone, Instant Knockout, Capsiplex Burn, PrimeShred and many others)

The vast majority of pills and supplements designed to aid your weight loss efforts contain caffeine. This is because caffeine is a well-known and fairly potent metabolism booster.

Caffeine is a stimulant – and one of the most widely used stimulants in the world. Like any drug, it can kill you at a high enough dosage. For humans, that dosage is around 10 grams. For comparison, one extra-strength Excedrin contains 65 milligrams (0.065 grams) of caffeine. A typical cup of coffee may contain anywhere from 80 to 180mg. A single Vivarin or other “pep” pill will usually contain 200mg.  A 24oz can of Monster energy drink contains roughly 270mg. The average person who consumes caffeine gets about 500mg (or 0.5 grams) per day total.

Consumption of caffeine typically causes vasoconstriction – that is, narrowing of the blood vessels. In this state, blood pressure increases. If you’ve ever had a caffeine headache, it is almost certainly due to the reversal of this process. For those sensitive to caffeine, it can cause jitters, restlessness, trouble sleeping and anxiety.

Pros: Caffeine definitely provides a marked increase in basal metabolic rate, which helps your body to burn more calories during rest. The anti-drowsiness effects may also make you feel more like participating in activities that burn calories rather than simply remaining at rest.

Cons: Over time, you can develop a tolerance to caffeine. Increasing the dosage to maintain the same level of effects can result in a number of unpleasant side effects including nervousness, insomnia, heart palpitations, and decreased motor coordination. This is a dependent condition called caffeinism, and it is unpleasant to recover (or “detox”) from.

Final Thoughts: Small amounts of caffeine are mostly harmless. Consuming larger amounts purely for the purpose of losing weight isn’t implicitly dangerous – but it has the potential to become dangerous as your body builds up a tolerance. If you’re going to use caffeine, stick to coffee or a good, natural tea – and leave the caffeine pills be.


Glucomannan (Lipozene, PhenQ, Phen24, Trimtone, Powher, Instant Knockout, Leanbean and others)

Few television ads can invoke the same level of channel change desire as the late-night paid specials about “male performance” – and if any weight loss pill has risen to that challenge, it’s Lipozene. If the ads are to be believed, this “revolutionary” pill will directly target body fat and help you lose massive amounts of it – all without any changes to diet or exercise. 

In reality, the active ingredient is Glucomannan – which is quite simply, a form of plant fiber. Like all fiber, it works by absorbing water and taking up space in your digestive system while providing little caloric or nutrient value. What makes Glucomannan noteworthy is how much water it can absorb to form a gel – which has lead to its’ use as a food additive for  its’ emulsifying and thickening properties. Here are some Lipozene pros and cons to help you decide whether it's everything they claim:

Pros: Glucomannan has been shown to lower blood sugar and improve cholesterol. Being a fairly potent form of dietary fiber it is also a very effective remedy for constipation. There are also studies showing that taking it in combination with a healthy diet can help with weight loss.

Cons: The claims made by late night advertisers are mostly unproven. While some benefit was seen by adding Glucomannan to a healthy diet, it performed just as well as several other kinds of dietary fiber also studied – and the results of those where not in line with the claims made by the these commercials. Also, remember that this is fiber. If you need additional fiber in your diet, all should be well. If not, you can probably guess the result. 

Final Thoughts: The makers of Lipozene settled a claim with the FTC for $1.5MM over their misleading ads for former brands FiberThin and Propolene in 2005. So it is probably best to check and verify claims before purchasing the product. 

Glucomannan can work in assisting your other weight loss efforts – and you can get it in a variety of forms from a variety of legitimate, trustworthy sources. Just don’t expect it to melt away substantial fat, if you are not eating healthy and/or active.


Orlistat / Tetrahydrolipstatin (Brand names Xenical or Alli)

Orlistat is marketed via prescription in most of the world, and over the counter in the United States and the United Kingdom. It has mild blood pressure lowering properties, but its’ primary effect is to reduce the amount of fat your body digests in the intestinal tract – making it primarily a weight loss medication. It has been available in the United States without a prescription since 2006.

Clinical studies have shown that Orlistat does indeed provide modest weight loss benefits when taken over time. At non-prescription strength, it prevents approximately 25% of dietary fat from being absorbed during digestion. Side effects can be prohibitive for some people – which include loose, oily stools, excessive flatulence, and frequent or urgent bowel movements. As a result, some of the weight loss properties of the drug are directly attributed to its’ users maintaining low fat diets to reduce these unpleasant symptoms.

Pros: Unlike most of the non-prescription options, this does work. When combined with lifestyle changes including diet and exercise, users typically lose 4-6lbs more per year than non-users of the drug. There is also typically mild blood pressure improvement.

Cons: When you start taking Alli or Orlistat, expect to spend significantly more time either in, or keeping very nearby to a restroom. If you’re unwilling to change your diet and reduce your fat intake significantly, do not expect this to ever change.

Final Thoughts: It works, but it must be combined with diet and exercise to see any real benefits.


Raspberry Ketones

Raspberry ketone is the primary aroma compound of red raspberries. It is also found in cranberries and blackberries. It is used as a natural flavoring, but is also one of the most expensive natural flavors available due to the low concentrations of the compound actually found in raspberries. Because of this cost factor, most of the products you’ll find marketed for weight loss are synthetically produced.

The only reason Raspberry ketone is sold as a weight loss remedy – and thus mentioned here – is that a study on mice showed that when mice were fed it at the rate of 2% of their diet, they showed statistically lessened weight gain than control mice. There is no evidence any amount of raspberry ketone consumed by humans has any effect on weight whatsoever. 

Pros: None. It doesn’t do anything.

Cons: If you wanted to mimic the single successful mouse study on record, you would need to consume at least 12 grams of raspberry ketone per day. To get that amount by eating natural raspberries, you’d need to consume a bare minimum of 6,600 pounds of raspberries. To do it with synthetic raspberry ketone pills, you would need to find the most insanely powerful pills they sell online and then triple the maximum dosage. Don’t expect this to end well however – raspberry ketones have been shown to increase body temperature, blood pressure and heart rate when taken in excess. Depending on your current physical condition, such an experiment could potentially kill you.

Final Thoughts: Raspberries are good for you in moderation. Raspberry ketone by itself in pill form however, is for all practical purposes useless.


Alpha-lipoic Acid (PhenQ)

Alpha-lipoic acid is an organic compound and antioxidant found in all human cells. It is also referred to as Acetate Replacing Factor, ALA, Biletan, Lipoicin and Thioctan, among other names.

ALA is produced in the mitochondrion, and it helps enzymes turn nutrients into energy. We produce small amounts of ALA naturally, and also take it in from red meats and organ meats such as kidney and liver, and vegetables such as broccoli, tomatoes, brussels sprouts, peas and spinach. One thing that sets alpha-lipoic acid apart from other antixidants is its solubility in both water and fat, while most antioxidants are only soluble in one or the other.

ALA has been used for some time as an alternative remedy for many ailments. These include diabetic nerve pain, lowering blood sugar, treating rheumatoid arthritis, glaucoma, migraines, altitude sickness, even Alzheimer's disease. Research has returned mixed results for the various uses for alpha-lipoic acid, and it is considered "possibly effective" for weight loss. It is not certain whether ALA is effective in treating ANY medical condition, and medicinal use of this product has not been approved by the FDA.

Human studies on ALA have shown a slight improvement in weight loss. It is suggested that this may be due to ALA suppressing the enzyme AMP-activated protein kinase (AMPK) in the brain, which can reduce feelings of hunger and simultaneously increase calorie burn at rest. In studies, it was found that subjects taking ALA supplements lost an average of 1.52 pounds more than the control group - during a 14-week weight loss program.

Pros: It seems to have a slight effect on weight loss when combined with traditional diet and exercise. There may also be beneficial properties for diabetics.

Cons: Because there are some mild effects on blood sugar, diabetics should use caution, particularly when already taking other medications. 

Final Thoughts: There are plenty of ways to increase your ALA intake simply through making healthy eating choices. If these simply aren't good enough for you however, supplements seem like a generally harmless way to get more. Do use caution however, as ALA supplements designed for weight loss (like PhenQ) contain other ingredients such as caffeine - which you may already be getting plenty of from other sources.


Green Coffee Bean Extract, AKA Chlorogenic Acid or CGA (PrimeShred, PhenGold, Leanbean and others)

In addition to caffeine, coffee beans contain a natural chemical compound and antioxidant called chlorogenic acid. This acid is broken down during the roasting process, therefore to get at it the beans must be consumed raw. 

It isn’t just in green coffee beans – you can also find chlorogenic acid in bamboo, potatoes, peaches, pears, apples, prunes, strawberries, blueberries, eggplants, Roselle leaves (used to brew many popular teas throughout the world) and other sources. 

The most prominent effect of chlorogenic acid is decreased blood pressure. Regular consumption of foods containing chlorogenic acid has also been shown to lessen the risk of gallstones if the daily intake is high enough. Over long-term intake, it can reduce glucose absorption in the intestines. Because of this, weight loss benefits are a distinct possibility.  There have been some studies to determine whether it causes weight loss, but there has not been enough consistent, independent research done to prove effectiveness just yet.

Pros: Improves blood pressure, may decrease risks of gallstones, could potentially help with weight loss but no strong evidence yet exists. It is an antioxidant, so it helps to prevent free radicals and cellular damage as do many other antioxidant vitamins and minerals.

Cons: While chlorogenic acid is shown to decrease blood pressure, caffeine will in turn increase it again. 

Final Thoughts: There are many, many ways to increase the amount of chlorogenic acid in your diet – but if for some reason you don’t like any of the foods noted above, adding some green coffee bean extract to your menu won’t hurt anything. Just don’t count on it as a miracle cure – any weight loss effects will be mild, and even those only if you maintain a healthy diet and exercise.



Meratrim (Sphaeranthus indicus & Garcinia mangostana)

Many drugs, chemicals or herbal ingredients used for weight loss were discovered by accident. Meratrim – the combination of two basic herbal ingredients – was the product of an intentional attempt to create a working weight loss remedy.

The first and primary ingredient is East Globe Indian Thistle – or sphaeranthus indicus. The flower of the plant has been used in traditional Indian medicine for centuries, and is applied in the treatments of a wide assortment of different and unrelated conditions. There still isn’t much scientific understanding of what exactly is in the flowers that effects the human body, or reliable research as to what those effects are. 

The second ingredient is Purple Mangosteen – or garcinia mangostana. This fruiting tree is of the same family as garcinia cambogia, and is a fairly multi-purpose plant. The inside of the fruit is frequently eaten, while the rind when dried and ground have been used to create a black dye, as well as medicinally to cure diarrhea. The bark has been used to treat dysentery. 

When combined in a 2-1 ratio to create Meratrim, these ingredients in a laboratory seem to work together to help the body burn stored fat and reduce the amount of new fat stored. In the real world, limited research is available.  In a small study group of people actively attempting to lose weight, those taking the herbal remedy lost an average of 1lb more than the control group per week. That’s the good news – the bad news is, the study in question was paid for by the people who make Meratrim.

Pros: So far as we can tell, there are few negative side-effects, and the limited study data available seems to show positive results.

Cons: The most promising studies on the product were sponsored by the makers of the product, so the accuracy of the results should be taken with a grain of salt (unless you have High Blood Pressure of course).

Final Thoughts: This could work. But remember that study participants who took Meratrim were actively losing weight – it just helped them lose slightly more than those on placebos. As with all weight loss remedies, you’re only going to see benefits when you apply healthy doses of diet and exercise to your plan. 


Conjugated Linoleic Acid or CLA

CLA is an Omega-6 fatty acid found naturally in beef and dairy products – and most people already get between 151 and 212mg of it per day from their diet. It is found most prominently in grass-fed ruminant animals, but it can also be found in smaller quantities in grain-fed sheep and cattle as well as certain mushrooms. CLA for supplement purposes is commonly synthesized from vegetable oils.

CLA is commonly marketed as a bodybuilding aid, and for anti-cancer properties. The latter use is based on some promising research done on mice, but there is a limited amount of evidence as to its’ effectiveness in this capacity for humans. Similarly, CLA has been shown to improve insulin response in rats while no matching results have yet been observed in humans. Of primary interest to this article, studies have shown significantly reduced body fat for mice fed a CLA-supplemented diet. Some studies on humans have shown significant weight loss improvement, while others have shown no difference at all.

Pros: Due to the number of smaller studies done on CLA in humans, we now have larger-scale cumulative research data showing that CLA is indeed helpful in reducing body fat – however the results are modest.

Cons: The synthesized forms of conjugated linoleic acid, while retaining the same basic chemical composition, are actually formed differently on a molecular level. As a result, synthetic CLA is processed differently in the body than natural forms – and this could account for the wide discrepancies seen across various studies. Your results could vary dramatically based on the source.

Final Thoughts: CLA is good for you, and can provide some benefits towards your weight loss goals. For best results however, seek out natural sources of it and avoid the synthetic variants commonly found in supplement pills. 



Forskolin / Coleonol

Forskolin comes from the Coleus forskohlii or plectranthus barbatus – also called the Indian Coleus. It is a tropical plant in the family Lamiaceae, which includes many common herbs and spices such as basil, mint, sage and oregano. It grows in various parts of the world, and is used in traditional medicine to treat heart disease, spasmodic pain digestive problems and hangovers. The root is used in parts of India to make pickles, and in Africa the soft, fuzzy leaves have been commonly used as toilet paper all the way up until modern times.

The reason forskolin or coleonol has become a weight loss fad, is that it stimulates fat cells to release stored energy much as the body does when you eat fewer calories than you burn in a given day. As such, it gained nationwide attention through Dr. OZ and has become an incredibly popular weight loss supplement.

There are important caveats however. First, helping the body to release stored fat only results in weight loss when you are already in a calorie deficit – that is, eating fewer calories than your daily burn. Second, most of the studies done on forskolin that show positive results were performed in a lab setting, or on animals. Human studies have returned mixed results with men seeing different effects than women and neither seeing significant weight loss precisely linked to the herb.

Forcing your body to release stored fat and burn it as fuel is one of the central goals of any good weight loss program. That’s why a hybrid diet / exercise program like ours works – because it gives the body no alternative but to pull upon fat reserves for sustenance. That said, there is little evidence that forskolin actively improves this process beyond what your body is already doing.

Pros: The plant is certainly not harmful, and based on its’ use in traditional medicines it may have a variety of positive effects. 

Cons: Weight loss is not proven to be one of those effects.

Final Thoughts: Coleus Forskohlii is a useful, multi-purpose herb – but not directly helpful for losing weight. 


Green Tea / Green Tea Extract (PhenGold, Trimtone and other supplement brands)

Green Tea originates from China, and is made from the leaves of the camellia sinensis, an evergreen shrub more commonly referred to simply as a “tea plant”. It contains a number of beneficial antioxidants and bioactives, including small amounts of caffeine. The reason it is cited as a weight loss aid however, is one of these in particular called epigallocatechin gallate, epigallocatechin-3-gallate, or simply EGCG. This is also found in black tea which is made from the same leaves of the same plant – but the concentration is much lower due to the withering / drying processes during preparation.

EGCG when combined with caffeine and other ingredients naturally found in Green Tea has been shown to boost metabolism, as well as increase the effects of specific hormones that trigger the breakdown of fat cells for fuel. There is even some evidence that it helps to suppress appetite.

As a result of these findings, tea has found its’ way into countless other forms of packaging – including quite a few of the natural weight loss supplements you’ll find on herbal shelves. 

Pros: Green tea hits the body in several different ways to help improve the fat-loss process. It is full of powerful antioxidants the body needs to function properly. It boosts metabolism, and may even reduce appetite.

Cons: While the list of positives seems long, the effects are all relatively mild. People with sensitivity to caffeine may encounter unpleasant symptoms, despite the low amount.

Final Thoughts: It’s really good for you on a number of levels, but it is not a miracle cure. Popping a green tea extract pill twice a day will probably do nothing for you if you don’t also eat a proper diet and make time for exercise.



From the 90’s up until 2004, if you picked up some random herbal one-per-day weight loss pills at a shop, there was a really substantial chance that these pills contained a combination of Caffeine and Ephedrine. The powerful mixture was incredibly popular because ephedrine – also used as a decongestant and asthma medication – is a stimulant very similar in nature to amphetamines (think Adderall) that proved quite powerful in aiding weight loss. It is also addictive, and capable of increasing heart rate and disrupting heart rhythm. In 2004 after several cases of fatal responses made headlines in the United States, ephedrine was restricted to use only in medications for asthma, colds, allergies or traditional Asian medicine. In 2006 as people continued to use these remaining sources specifically for the ephedrine in them, it was banned from dietary supplements entirely.

Synephrine is related to ephedrine, but is less powerful and lacks the same degree of regulation. It is found in oranges and orange juice at very low concentration, and is often extracted from unripe oranges through a drying process. It has become quite popular as a weight loss drug in place of ephedrine, in spite of side effects similar to ephedrine and a similar (if slightly lessened) potential for addiction. Studies on its’ effectiveness are few and far between.

Pros: It works similarly to ephedrine in directly boosting resting metabolism

Cons: It shares many of the same risk factors as ephedrine as well, and may be addictive. 

Final Thoughts: If you examine the list of stimulants that are banned in various competitions – or banned from use in dietary supplements entirely due to risks of potentially deadly side effects – you’ll quickly identify that synephrine bears similar risks and currently lives in a sort of “loop-hole” spot on the map. As such, we cannot in good conscience recommend using it.


Prescription Weight Loss Drugs

There are some legitimate, FDA regulated prescription options that require a visit to your doctor to get your hands on. As you might expect, these drugs live in regulated status for good reasons such as potential side-effects or dangerous interactions with other drugs. They can also be expected to provide more reliable results than the group above due to the amount of research and testing required for approval. Additionally, you don't have to seek out a fat farm's independent research just to get to the truth about these - their complete information can be found on many reputable medical websites such as Drugs.com and RXList.com. We have, however, provided the most popular options here, to better inform your decisions.


Bupropion Hydrochloride / Naltrexone Hydrochloride (Contrave)

Contrave is an antidepressant that can reduce appetite. As such, it is commonly used in combination with diet and exercise regimens to help reduce weight faster. It is a combination of Buproprion and Naltraxone – both of which affect appetite, and which are said to work more effectively in combination than either would alone. The specific combination is not FDA approved for use as an antidepressant or for smoking cessation, however it is sometimes prescribed for these as well.

Buproprion alone is specifically marketed for its’ antidepressant properties under the branding Welbutrin, and can be an effective tool in quitting smoking. It is in fact one of the most prescribed antidepressants in the United States. Because of the specific way that it works, it is often combined with other antidepressants to increase their over-all power without risking severe adverse side effects. It does however carry some risks, in that some users have been known to become suicidal when first beginning dosage. Epileptic seizures are another potential side effect.

Naltrexone works to inhibit the effects of opiods in the body, and is thus widely used to help with addictions and alcoholism. Given that food can have incredibly powerful addictive properties, the function of Naltrexone becomes fairly clear.

Pros: As prescription drugs go, Contrave is fairly low-risk and has proven beneficial for those already on a weight loss plan.

Cons: It should not be taken by those with a history of eating disorders or seizures.

Only your doctor can recommend whether any prescription drug is suitable to help you lose weight. 


Lorcaserin (Belviq)

Belviq is a relatively new weight loss drug that operates by affecting serotonin receptors in the brain, and works as an appetite suppressant. It is FDA approved for use with patients having a Body Mass Index greater than 30. 

While side effects are few and generally mild, some concerns were raised during the FDA approval process about tumor growth in laboratory rats. The medication also has addictive properties, and can cause hallucinations at higher doses than prescribed. It was determined not to be a cancer or heart valve risk and approved for use in 2012.

Pros: In clinical trials, Belviq produced a 5% loss in body fat over 1 year for 33% of test subjects. Of those taking placebos, 16% achieved the same results. It does work – just not for everyone.

Cons: This drug is only approved for use in certain situations, and it has a fairly long list of other drugs it should not be taken with. The success rate of achieving 5% body fat loss per year only comes to about 17% beyond the control groups in studies. 

Only your doctor can recommend whether any prescription drug is suitable to help you lose weight. 


Phentermine (Adipex-P, Suprenza)

Phentermine – or phenyl-tertiary-butylamine if you want to get scientific – is a psychostimulant closely related to amphetamines. It works primarily by reducing hunger perception. It also releases norepinephrine and epinephrine into the circulatory system which triggers fat cells to break down stored fat for energy. Because of its’ similarity to amphetamines, it is a Schedule IV controlled substance in the United States. Phentermine has been around since the 1950’s, but availability has varied across the globe.

The most recent human study to date was performed in Korea, and saw men and women lose an average of 5lbs per month. It should be noted however that participants were also on a 1,500 calorie-per-day eating plan. Of those in the study, 33% of the placebo group attained 5% body fat loss, versus 87.5% for the phentermine group.

Pros: The drug works – the fact that it’s been in use for several decades alone attests to that.

Cons: It’s a controlled substance, and can cause various side effects including arrhythmia, hypertension and changes to libido. As with all weight loss drugs, a low calorie diet is also required at minimum.

Only your doctor can recommend whether any prescription drug is suitable to help you lose weight. 


Phentermine & Topiramate (Qsymia)

Topiramate is an anti-epilepsy drug that’s been in use for about 20 years now. In 2012 however, it was approved to be used in combination with Phentermine as a weight loss medication. The brand name is called Qsymia.

Phentermine is a stimulant and appetite suppressant. Topiramate has weight loss side-effects. Combined they tend to improve cholesterol and glycemia as well as decrease blood pressure. The reason the drugs work together to produce these specific results is largely unknown – but clinical studies so far have shown promising results just a bit better than Phentermine produces alone. Since this drug combination was only approved in 2012, more research is needed to determine all of the possible side effects.

Pros: Improvement to cholesterol and blood pressure as well as increased weight loss when combined with an effective diet program.

Cons: Users of Qsymia are strongly warned of harm to unborn babies if the drug is taken while pregnant. Other side effects including suicidal behavior and increased heart rate are reported.

Only your doctor can recommend whether any prescription drug is suitable to help you lose weight. 



Diethylproprion is produced through a reaction between diethylamine and amfepramone, a stimulant very closely related to Welbutrin. It works by suppressing appetite and increasing heart rate and metabolism. It can be habit forming and have withdrawl symptoms on cessation.

In clinical studies, diethylproprion increased weight loss over a 6 month period by roughly 6.5% over placebo. Side effects can be significant however, and include blurred vision and impaired thinking. It can aggravate existing heart and blood pressure conditions.

Pros: Like many of the weight loss drugs cited so far, studies show that this medication does produce results.

Cons: There are a number of medical conditions with which taking this drug could be dangerous.

Only your doctor can recommend whether any prescription drug is suitable to help you lose weight. 


Phendimetrazine (Bontril PDM / SR)

Phendimetrazine is a new formulation of a simpler and older drug called Phenmetrazine (most popularly branded Preludin). Phenmetrazine was originally developed in the 1950’s in Germany as an appetite suppressant. The goal was to produce a drug with comparable appetite suppressant capabilities to amphetamine, but without as many side-effects. It was a success in this, with fewer reported cases of nervousness, hyperexcitability, euphoria and insomnia than amphetamine. Unfortunately it was also easily abused. It was classified a narcotic in 1959 in Sweden and taken completely off the market in 1965. It was widely abused in America in the 1960’s and 70’s and is still abused throughout the world today.

Phendimetrazine is converted into phenmetrazine in the body, in a process that provides more of a “slow-release” for the drug and thus helps prevent its’ abuse while retaining the beneficial appetite suppressant capabilities originally intended.

Pros: It does what it was developed to do.

Cons: It’s still a powerful controlled substance and considered just as potent as amphetamine. If you ever actually get prescribed this drug, use at your own risk.

Only your doctor can recommend whether any prescription drug is suitable to help you lose weight. 


Benzphetamine hydrochloride (Didrex)

Just like Phendimetrazine above, Benzphetamine hydrochloride (branded Didrex) is designed to break down in the body to form something else. In this case, the resulting two drugs formed are amphetamine and methamphetamine. Scared yet? Not to worry, unlike the raw substances it breaks down into, Benzphetamine is a fairly low abuse risk drug on account that it must pass through the liver before the resultant amphetamines are formed – producing a significantly delayed reaction. 

The fact still remains that the resultant drugs produced are amphetamine and methamphetamine. Amphetamine has been around since 1887 and is still used today to treat ADHD in some circumstances. Even at prescribed dosages, amphetamine may cause euphoria and changed sex drive. It was notoriously used by soldiers in World War II.

Methamphetamine is an extremely potent central nervous system stimulant which has also been used under prescription to treat ADHD. In low doses it increases alertness, concentration and energy as well as reduces appetite. It is rarely prescribed today due to abuse potential and human neurotoxicity.

Pros: There’s no doubt that amphetamine and methamphetamine will reduce your appetite and give you more energy.

Cons: You will test positive for meth in drug screenings. You’re only going to get ahold of benzphetamine if you are morbidly obese and unable to lose weight with diet and exercise alone.

Only your doctor can recommend whether any prescription drug is suitable to help you lose weight. 


Sibutramine (Meridia)

Sibutramine (hydrochloride monohydrate salt if you want to be scientific) is an appetite suppressant that was pulled from the market in 2010. We’re including it here because it is still available in some countries, and is still being sold illegally in many more.

Sibutramine is structurally similar to amphetamines, but works in a somewhat different way. In the body it causes increased levels of norepinephrine, serotonin and dopamine. The difference between Sibutramine and Amphetamine is that amphetamine forces the body to produce more of these neurotransmitters – while sibutramine simply prevents the body from reabsorbing them as quickly as normal.

Sibutramine can cause substantially higher blood pressure and heart rate, and in some cases cardiac arrythmias, seizures and more. The drug came under scrutiny in 2002 and 2005 due to reported cases of sudden death, heart failure and renal failure, and was eventually discontinued by the pharmaceutical company. 

In 2008, the FDA issued an alert to consumers naming 27 different dietary supplements for weight loss that illegally contain undisclosed amounts of sibutramine. You can read this press release by clicking here. In 2011 the FDA warned of 20 brands of dietary supplements found to  be tainted with sibutramine. 

The FDA has provided many more warnings about weight loss drugs over the years which contain amounts of several controlled and dangerous substances. You can find out more about these by clicking here.

Pros: None – this drug is no longer legally available for use due to safety concerns.

Cons: None – this drug is no longer legally available for use due to safety concerns.

Only your doctor can recommend whether any prescription drug is suitable to help you lose weight. 



In Summary

While some of the reviewed weight loss supplements lack research showing their effectiveness, there are a few that have been proven to work. That said, those that do work are far from “revolutionary” or “miracle” pills. The few seriously powerful drugs in the mix are just that – powerful drugs. Drugs that are highly controlled due to either being highly dangerous, heavily abused or both.

Ultimately, no diet pill or weight loss medication can make up for an unhealthy lifestyle – and this is their universal Achilles heel as a weight loss method.

Only when combined with a healthy diet and exercise can any weight loss supplement be truly effective – and only under the same conditions can you expect to maintain your results.


About the Author

Jeremy Ryland is a certified personal trainer (CPT), group fitness trainer (CFT) and certified clinical nutritionist (CCN). When he's not actively helping others improve their health or writing blogs, he can usually be found testing out the latest new off-road gear on his mountain bike.



The Weight Crafters Fitness & Weight Loss Blog feed is made available for educational and informational purposes only as well as to give you a general understanding of fitness, weight loss and overall nutrition, and is not to provide specific professional medical or healthcare advice.

By using this blog site you understand that there is no professional client relationship between you and the content publisher. The Blog/Web Site should not be used as a substitute for competent medical, exercise, nutritional or diet product advice from a licensed professional provider in your state.

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