Best Rated Diet Pills Free Trial Scams


Phentaslim claimes to target three key areas of weight loss using ingredients that are supported by scientific evidence. Phentaslim does, however, contain stimulants.

Below we have reviewed Phentaslim against our review criteria to help consumers make an informed decision.


Phentaslim Pros
  • 30-day money-back guarantee
  • Ingredient quantities provided
Phentaslim Cons
  • Stimulant content may cause side effects
  • Not all of the ingredients have been proven to boost weight loss

Phentaslim is marked as ‘Approved’ as it meets all of the points in our ‘Approved Criteria’. To find out more about how Phentaslim performed against our criteria click here.

Phentaslim Review

Phentaslim contains a range of ingredients (16 in total) and is claimed to target several key areas of weight loss. Ingredient quantities are provided and a money-back guarantee is offered with every purchase.

Claimed weight loss benefits

This product contains ingredients that are believed to work to boost metabolism, burn fat and suppress the appetite; it is thus claimed to target three of the five key areas of weight loss.

How Phentaslim Works

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The official website states that Phentaslim works as both a fat burner and a metabolism booster, which should, in theory, cause the consumer’s body to burn greater amounts of fat faster. It also claims to curb the consumer’s appetite, which means that the amount of calories consumed should be reduced, consequently helping with weight loss. As well as this, the website states that it increases the body’s metabolism and boosts energy levels.

Vitamins and Amino Acids

The addition of amino acids is said to help aid the breakdown of fatty acids, as well as boost performance and elevate the consumer’s mood. The inclusion of vitamins and minerals may also be beneficial: the essential B Vitamins, including B1, B2, B6 and B12 supposedly means that the body is able to support an increase of metabolism, helping weight loss to be achieved. Other potential beneficial functions of these vitamins include maintaining healthy skin, hair and muscle tone, enhancing immune and nervous system functions, and promoting cell growth and division.

Guarana Seed

One of the key ingredients is the Guarana seed, which is naturally high in guarana, which is a source of caffeine. It may therefore offer extra energy, increases alertness, and help to suppress the appetite.

Caffeine Anhydrous

As well as in guarana, caffeine is also contained within the product as its own ingredient. Caffeine anhydrous simply means that it is caffeine without water. This ingredient is claimed to act as a metabolic stimulant that increases wakefulness, alertness and focus.

Green Tea

Phentaslim also contains green tea, which contains polyphenols that are believed to increase thermogenesis without increasing heart rate, which in turn is said to stimulate fat oxidation, reduce body fat, and reduce cholesterol levels and blood pressure, encouraging weight loss.

Panax Ginseng

The official product website states that Panax ginseng helps to support metal performance and well-being, with a focus on maintaining the body’s immune system. There is no mention of how Panax ginseng may contribute to weight loss, although the ingredient is sometimes said to increase energy and athletic performance levels.


The inclusion of Cayenne (also known as Capsicum extract) is believed to have thermogenic properties which cause the metabolic rate to increase, as well as increasing the ability to absorb other ingredients by increasing the blood flow to the responsible receptors and increases the body’s temperature, allowing more calories to be burnt.

L-Tyrosine and L-Carnitine

The addition of L-Tyrosine is also claimed to help counter fatigue and the stresses associated with intense and heavy workouts, meaning that the consumer can, in theory, exercise more efficiently and possibly recover quicker. L-Carnitine also has the reported effect of breaking down the lipids to give increased metabolic energy. An increased consumption of this ingredient is sometimes believed to help to reduce fat mass, increase muscle mass, and reduce fatigue.

Key Phentaslim Ingredients

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Vitamins and Amino Acids

A selection of vitamins and amino acids are present in this product; namely: L-carnitine and L-tyrosine, and vitamins B6, B1, B2, and B12. On the product website, these ingredients are stated to have a number of benefits, ranging from improving energy levels to suppressing the appetite and burning fat. Vitamins and amino acids are essential for the maintenance of good health. They are required for a great variety of bodily functions, from helping to repair cells to building new cells and improving the immune system.

Guarana Seed

Guarana is the name of a plant that is best known for its use by tribes in the Amazon. It is the seeds of this plant that can often be found in supplements. Guarana seeds are thought to act as stimulants; they contain a significant amount of caffeine as well as theobromine and theophylline – chemicals that are very similar to caffeine. As such, guarana is thought to boost energy levels, but has also been used to treat a great range of conditions in traditional medicine.

Caffeine Anhydrous

Caffeine anhydrous refers to the caffeine that is present in everyday products such as tea and coffee, but without the water. The ingredient is best known for its stimulant qualities; it has the potential to boost the central nervous system, causing a feeling of awareness and boosting energy levels. This effect can impact some people more than others; those who are sensitive to caffeine may experience unpleasant side effects, such as jitteriness and insomnia.

Green Tea

Green tea is made from the leaves of the Camellia sinsensis plant – the same plant that is used to make black tea. In comparison to black tea, green tea is thought to contain lots of polyphenols and antioxidants. The substance is consumed as a beverage all over the world, but extract can also be taken from green tea for use in supplements. It is thought to have the potential to treat a great range of health conditions, from osteoporosis to cancer.

Panax Ginseng

Panax ginseng is the name of a plant; it is the root of this plant that is used as an ingredient in traditional medicine. The substance is thought to have beneficial effects for conditions such as hayfever, Alzheimer’s disease, and cancer – to name a few. Panax ginseng is commonly added to supplements for its potential benefits to certain aspects of brain function, such as memory and concentration, as well as for its supposed athletic performance-enhancing effects.


Cayenne pepper contains a substance called capsicum; it is this chemical that is believed to hold properties that may be beneficial for health. It has been used in traditional medicine to treat a variety of conditions, ranging from gastro-intestinal problems to malaria and muscle spasms. The ingredient is also thought to have the potential to reduce pain sensations.

L-Tyrosine and L-Carnitine

L-tyrosine and L-carnitine are both amino acids. Amino acids are known as the building blocks of proteins, and are essential for maintenance of the human body. These two amino acids are made by the body, but can also be found in a number of common foods. Besides treating deficiencies of the amino acids, L-tyrosine and l-carnitine may be taken as supplements for the treatment of conditions such as attention deficit hyperactivity disorder (ADHD) and heart disease.

Clinical Studies

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Clinical trials are research studies that explore whether a medical strategy, treatment or device is safe and effective for humans. They are also used to show what medical approaches work best for certain illnesses. A lot of scientific research is done first before any clinical trial takes place, and then the next step is normally animal testing to see how the approach affects a living body, and if it could be potentially lethal. However, what does work well on animals in a laboratory environment wouldn’t necessarily work in the real world so that’s when tests on humans are needed.

Guarana Extract

Few studies have been undertaken to test the effects of guarana on weight loss, particularly on its own. A few studies have been done that have looked at guarana when combined with other ingredients. One study, for example, looked at a mixture of guarana and green tea (containing caffeine) – all ingredients that are present in this weight loss supplement. The results of this trial suggested that the mixture could significantly increase energy expenditure, but also that it increased blood pressure. This study was small, using only 14 subjects, and so more studies on the ingredient are certainly required.


Another ingredient found in Phentaslim is Caffeine Anhydrous. This is effectively caffeine yet under a different name, and is the equivalent to a very strong cup of coffee. Experimental evidence has suggested that caffeine may be an effective metabolism booster, as shown in the following clinical trial.

A clinical study carried out by the American Society for Clinical Nutrition in 2006 set out to assess the relation between caffeine intake and respective weight change over a twelve year period. They did so by conducting a study of 18,417 men and 39,740 women, with no chronic diseases, who were followed from 1986 to 1998. Caffeine intake was assessed repeatedly every two to four years, and weight change was calculated as the difference between the self-reported weight in 1986 and in 1998.

The results of the study showed that long-term studies have linked higher coffee consumption with a lower risk of developing type 2 diabetes mellitus. Weight gain is a major determinant of diabetes, and it is possible that a beneficial effect of caffeine on weight might contribute to the inverse association between coffee and diabetes. This hypothesis was supported by the fact that a number of short-term studies had showed an increased metabolic rate and thermogenesis following caffeine consumption.

Green Tea

Although only present in a small quantity, green tea extract is found within the product and there are a number of studies into the effects of green tea.

A study carried out at the Department of Human Biology, Nutrition and Toxicology Research Institute at Maastricht University in the Netherlands discovered that drinking green tea can help a person significantly lose weight and maintain the lower weight once pounds have been lost. These healthy ingredients contributing to weight loss may be discovered in all green teas.

A further study published by the Journal of Nutrition in their February 2009 edition concluded that consuming catechin, an ingredient discovered in green tea, led to higher levels of exercise-induced abdominal fat loss in overweight and obese adults. This was proven in how the triglycerides in the participants’ bloodstreams were also lower than those who did not drink green tea. Consequently, conclusions from this study presented how drinking green tea for weight loss can benefit an overweight or obese person when tea drinking is combined with regular diet and exercise.

Panax Ginseng

Panax ginseng has not been well-studied for its potential weight loss effects, although a few preliminary trials have been performed, most of which used small mammals as subjects. One such study was published in the journal ‘Phytomedicine’ in 2002 investigated the effects of Panax ginseng berry on mouse subjects. The animals were given injections of Panax ginseng extract every day for a period of 12 days. The authors noted that by the fifth day, the mice that were given Panax ginseng had significantly reduced blood glucose levels. By the end of the trial, an increase in glucose tolerance was reported, as well as benefits to blood glucose exposure and body weight.

Phentaslim Side Effects

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It is claimed that the product is safe because it is made in a GMP-certified facility and the individual ingredients are completely natural and approved by the FDA. No side effects are mentioned. However, just because an ingredient is natural does not mean that it is safe – some natural ingredients can cause side effects.

In some customer reviews of the product, headaches and dizziness have been reported as side effects, and this may stem from the high quantities of caffeine contained within the product. Equally, some customers have reported troubling getting to sleep if they take two tablets within a day, and so this is something you should consider before taking the supplement. This can vary from consumer to consumer.

If you have any allergies or sensitivity to caffeine, or have a history of cardiovascular disease or liver disease, you should avoid this product and make sure to seek medical advice before taking weight-loss supplements like Phentaslim. Since the product has not been the subject of any clinical trials, the safety is Phentaslim is not known, and other side effects may be experienced.


The high caffeine content may cause problems such as anxiety, insomnia, nervousness, nausea, headaches and dry mouth. More seriously, it may cause an increase in blood pressure and heart rate.

Cayenne Pepper

The cayenne pepper may cause flushing, rashes and sweating.

Panax ginseng

Panax ginseng is believed to be possibly unsafe when taken by mouth for long periods of time. It is said that the ingredient has hormone-like effects, and has been associated with problems such as menstrual problems, breast pain, diarrhoea, mood changes, dizziness, liver problems, severe allergic reactions, high or low blood pressure and increased heart rate, amongst others.

How to Use

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It is recommended that you take two capsules a day orally, preferably one 20 minutes before breakfast with water, and another capsule 20 minutes before lunch, again ensuring this is taken with water. It is important that the consumer does not exceed two capsules in one day, or take the capsules after 6pm due to the caffeine content within the product.

The consumer should be following a balanced, low-fat diet in order to achieve faster results, and this should be combined with regular exercise. Similarly, the capsules are recommended to be taken after food and in cycles of three months on and one month off until your target weight has been achieved.

It is stated that you should not take the product if you are pregnant, breastfeeding, have a BMI of less than 18.5, or are under the age of 18. The official website recommends that you consult a doctor before taking the supplement if you have a pre-existing health condition or if you are taking any medication.

If any problems occur, it is important that the consumer consult their doctor immediately and refrain from continuing to take the weight-loss supplement. It should also be noted that vegetarians should not take Phentaslim, due to the small amount of gelatin contained in the capsule gel. You can read on more about how to take Phentaslim on the official website FAQ.

Who Makes It?

Optimum Nutra Inc. is the company behind Phentaslim. Their official website is straight to the point – they list the products they manufacture and stock which includes Phentaslim, Prostailen and Superfruit Slim. They supposedly sell these products to retail outlets via websites and telephone sales. They say their company was established in 2011 to serve the fast growing requirements of the weight-loss supplement industry. They claim to pride themselves on their mission to bring their consumers the most pure natural ingredients possible, and commit themselves to quality, safety, and efficacy, adhering constantly to strict Pharmaceutical Good Manufacturing Practices (GMP).

Other than this, their website states that they distribute their full product range to any size of business. Links to their respective product websites are also available on this site, but there is little else to suggest their reputation, establishment, or expertise as a company.

Where to Buy Phentaslim


The only place where you can get hold of Phentaslim is at the official website, as there is no Amazon page for the product and there does not seem to be any other retailer selling the product online.

Phentaslim is available for purchase in a number of different quantities – a starter supply, containing enough for a 1 month supply costs £34.95, with a current discount on the recommended retail price of £59.95. Alternatively, it can be bought as part of a 2 month supply, with the respective units becoming better value depending on the greater quantity purchased. The website claims that this is their most popular package, and it will set you back £59.95, although this does come with free shipping, unlike the 1 months’ supply. Finally, their package that is recommended for those looking to lose 20lbs or more contains three bottles of the weight-loss supplement for £94.95, plus one free bottle, with free shipping also included.

An important point to note is that every order bought of Phentaslim comes with a 30-day money-back guarantee from the purchase date, meaning that if you are unhappy with the results of the product, you can get in touch with the company behind Phentaslim, who will refund the consumer the full cost, minus a small handling fee.

Does Phentaslim Meet our Approved Criteria

Money-back-guarantee: Yes, the company offers a 30-day money-back guarantee.

One-off payment: Yes, purchasing the product consists of a one-off payment.

Manufacturing Standard: It is claimed that the product is made under GMP standards.

Accompanying Diet Plan: There is no mention of an accompanying diet plan, however the product does promote a healthy lifestyle.

Ingredients and quantities disclosed: Yes, this information is available on the website.

Company contact details readily available: Yes, this is available.

Phentaslim does meet our ‘Approved’ criteria as it meets all of the points on the ‘Approved criteria’.


Overall Verdict

This product has a long list of ingredients, some of which have been the subject of successful clinical trials. Others however have not been studied for their effects on weight loss in humans. The product may have side effects associated with the stimulant content, but none of the ingredients are known for causing severe side effects. The company offer a 30-day money-back-guarantee, so if you are unhappy with the product, you can return it for a refund.

Our Top Approved Diet Pill 2017


Gravitate Nutrition

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Why Is Graviate Nutrition an Approved Supplement?

  • Unique 3 product system
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  • 60-day money-back-guarantee
  • FREE worldwide shipping

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One response to “Phentaslim”

  1. Roxanne says:

    Hey I’m very interested in trying this product. I noticed alot of diet pills reviews cause problems with the liver. Is there any possibility this will happen with this medication ?

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