Synedrex is a fat burner manufactured in the USA by Metabolic Nutrition. The company is based in Florida and although it’s certainly a reputable company, I am going to begin this review by stating that Synedrex is not a fat burner I would consider using myself.

The Synedrex sales page on the Metabolic Nutrition website says Synedrex is “the most powerful thermogenic agent on the market, bar none.”

I encounter claims like that all the time. Talk about blowing your own trumpet. Some companies do this all the time.

Every time I see such claims, I expect to discover the supplement in question is loaded with stimulants. More often than not I am right and it’s certainly the case with Synedrex.

If you are a hardened caffeine junkie who is looking for a fat burner that may give you extra energy to train, you may be okay with a product like Synedrex.

However, if all you need is a good diet pill to control your hunger and help you to burn your fat faster, Synedrex is going to be a poor fit for your needs.

If you are thinking of using Synedrex Fat Burner, this review provides you with all the pros and cons. I am going to detail what kind of benefits it may provide and give you an idea about the side effects that you may have to endure.

At the end of the review, I am going to suggest a fat burner you may want to consider using instead of Synedrex. The cost per bottle is more or less the same but the product I will recommend offers a greater level of fat loss support, is vegan-friendly, and has a 60-day money back guarantee.

Synedrex Fat Burner: The Promised Benefits

  • Strong appetite suppression
  • Extreme, long-lasting energy
  • Enhanced mental clarity and focus
  • Metabolic thermo accelerator

How to Use Synedrex Fat Burner

A Bottle of Synedrex Fat BurnerThe dose is one to two Synedrex capsules per day. New users are advised to begin with just one capsule per day, taken with breakfast.

Presuming there are no tolerance issues, it’s possible to take a second capsule at lunch to provide a mid-day energy boost. Metabolic Nutrition also says it’s permissible to take two Synedrex capsules at breakfast. Bearing in mind the stimulant-rich nature of this supplement, doing so is probably a bad idea.

Regardless of how you schedule the doses, the maximum dose is two capsules per day.

Although Metabolic Nutrition fails to mention this, it would be inadvisable to use this supplement alongside other stimulants such as tea, coffee, or energy drinks. Doing so would greatly increase the risk of side effects.


How Synedrex Fat Burner Works

The main thing this supplement appears to do is pump you full of stimulants.

Stimulants like caffeine can be good for boosting energy levels. They also improve concentration and focus.

When used in sufficiently high quantities, stimulants may reduce appetite as well by making you feel too wound up to eat.

Some stimulants also boost metabolism by increasing thermogenesis. Caffeine is one of them. However, although it has proven value in this area, the problem with caffeine is your body adapts to its presence. This makes it less effective. The same is true for other stimulants as well.

Certain natural ingredients like green tea and cayenne, also increase thermogenesis. Both are better options than stimulants because their ability to accelerate fat burning remains consistent. Even if you continue using them for a long time.

Things to Bear in Mind

Like other weight management products, Synedrex is a supplement. It’s important to understand what a supplement is and never to see any supplement as a magic pill.

The word “supplement” refers to something you get or use in addition to something else. For instance, Some people work two jobs to “supplement” their income.

Diet pills and other weight loss supplements, supplement the efforts you are already making by controlling your diet.

In this case, it’s important not to see Synedrex as a product that provides an excuse not to try and eat healthy foods. The pills will work best if you use them alongside a healthy diet that contains nutritious foods that are low in fat and sugar.


Synedrex Fat Burner Ingredient List

One capsule provides 650 mg of the Synedrex Extreme Stimulant Weight Loss Solution Proprietary Blend.

This contains the following 12 ingredients:

  • Caffeine Anhydrous
  • Eria Jarensis Extract
  • Grains of Paradise
  • Bitter Orange Extract (Standardized for N-Methyltyramine, Octopamine, Synephrine)
  • Yohimbine HCL
  • Higenamine (Norcoclaurine)
  • Hordenine
  • Huperzine A
  • N-Methylphenethylamine
  • L-Dopa (standardized to 99%)
  • Poly-Thyronine
  • Naringin


Synedrex Ingredient Evaluation

It’s hard to evaluate supplements that use proprietary blends. There is no way to find out if the ingredients are present in useful amounts or predict how bad the side effects might be if the doses are too high.

Caffeine Anhydrous

I started this Synedrex review on a negative note by saying it contains too many stimulants. However, that does not mean I think caffeine is bad.

Far from it. Caffeine can be very good for boosting energy and clearing the mind. Furthermore, research supports its abilities as a thermogenic fat burner.

Unless you are cursed with an abnormally low tolerance or have become immune to its stimulatory effects, caffeine can help you to burn fat faster. It’s not caffeine that’s bad, it’s overly high doses.

Combining caffeine with other stimulants also increases the risk of ill effects.

Experts suggest not consuming more than 400 mg of caffeine per day. That’s from all sources, including tea, coffee, and energy drinks.

A lot of the best fat burners provide no more than 100-150mg per dose and never provide more than 400mg in any 24 hours.

Eria Jarensis Extract

This chemical is known by many names including N,N-dimethylphenethylamine. It’s a form of phenethylamine.

Regardless of the name it appears under, Eria Jarensis is a stimulant. It’s occasionally used in weight loss pills and as an athletic performance booster but WebMD casts doubts on the ingredient’s potential in any of these areas. WebMD says  using this ingredient may also have serious health implications.

Grains of Paradise

This is probably the best ingredient present so it’s a great pity we will never know if it is included in a useful amount.

Grains of paradise is a seed extract. It comes from the plant Aframomum melegueta. It’s a member of the ginger family.

The results of a study involving 19 male volunteers (aged 20-32) show grains of paradise was effective for reducing body fat.

The researchers say the ingredient increases fat loss by activating brown adipose tissue (BAT).


Bitter Orange Extract

OrangesThis extract comes from a citrus fruit called citrus aurantium. It provides three stimulants:

  • N-Methyltyramine
  • Octopamine
  • Synephrine

Synephrine is generally considered to be the most potent of the three.

I do not like this ingredient. I would be very nervous about using it. In fact, I would never use it at all.

Synephrine is a powerful stimulant. It places the body into a survival mode called fight or flight. The condition produces numerous biological, chemical, and hormonal changes in the body. One of the reactions is loss of appetite.

The prescription drug, Phentermine, reduces appetite in the same way. It’s known for causing many unpleasant side effects, many of which are attributable to its ability to prolong fight or flight.

The condition helps you to fight harder or retreat from danger faster. However, it would normally only last a short time. Experts agree it is unwise to prolong the fight or flight stress response.

Synephrine is associated with unpleasant side effects too and the results of a risk assessment conducted in 2017, suggest that “consuming high amounts of synephrine, especially in combination with caffeine and physical exercise, is associated with an increased risk of adverse effects on the cardiovascular system.”

Yohimbine HCL

This is another stimulant. It comes from the bark of the Yohimbe tree and has a long history of use as an aphrodisiac.

To this day, yohimbe extracts are used as a natural remedy for erectile dysfunction (ED). It appears to combat the condition by improving blood flow to the penis.

Yohimbine is also present in supplements that aim to boost athletic performance or enhance mood. However, according to WebMD, there is no evidence to support using yohimbine in these ways.

WebMD also makes it clear that the yohimbine yohimbe provides may have the potential to cause severe side effects and should never be used without medical supervision:


Higenamine (Norcoclaurine)

Higenamine (norcoclaurine) is a chemical compound present in certain plants. By now, you probably won’t be surprised when I tell you it’s a stimulant.

Although it is legal to put higenamine in supplements for sale in the UK, USA, and Canada, the health risks it may present are not fully understood.

This ingredient’s main value is as a performance booster. However, if you are planning on competing in athletic competitions or sports, using higenamine may throw a huge spanner in the works. It was added to the World Anti-Doping Agency (WADA) Prohibited List in 2017.

Higenamine is classified as a beta-2 agonist, which means it is prohibited at all times, both in and out of competition:



Hordenine is a barley extract. It functions as a stimulant and is chemically similar to synephrine. It’s another ingredient I urge you to avoid.


Huperzine A

Huperzine A is a moss extract that is popular in traditional Chinese herbal medicine. Elsewhere in the world, you are more likely to encounter Huperzine A in nootropic supplements that aim to support improvements in cognitive function.

The ingredient’s potential in this area is pretty good. Research shows it helps protect neurons from being damaged by oxidative stress. Researchers are currently exploring its value as a potential treatment for Alzheimer’s Disease.

So what’s it doing in a fat burner? Your guess is as good as mine.



N-Methylphenethylamine is a compound that occurs naturally in the body. It’s also present in certain plants. I was unable to find any good reason why its presence would offer value to a formulation such as this.



L-Dopa (Levodopa) is an amino acid that’s present in certain plants and animals. It’s also naturally occurring in the human body.

L-Dopa is a precursor to the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline).

According to an article in Frontiers in Neurology, L-Dopa treatments are the most effective pharmacological therapy for treating the motor symptoms of Parkinson’s disease.

This is not an ingredient I would expect to see in a fat burning formulation. It’s unlikely to offer any useful benefits and could be more trouble than it’s worth. It can present several side effects including drowsiness, headaches, nausea, and dizziness.

L-Dopa also appears to present additional risks to older individuals.
Examples include confusion, hallucinations, and psychosis:

When used with the correct medical supervision, as a treatment for Parkinson’s disease, L-Dopa appears to be beneficial but, I have to say it again, I can’t see any good reason for its inclusion here.


Poly-Thyronine consists of two T” thyroid hormone metabolites. Although it may accelerate metabolism, research suggests it may also suppress the HPT axis. This has the potential to cause some pretty undesirable problems.

Research published in Endocrinology (Endocrine Society journal) ends with the following conclusion: “The implication of this finding is that, for a given dose, the detrimental effects of T2 on the HPT axis may preferentially occur before the intended metabolic ones. Thus, for the time being, these new data should compel users of T2-containing supplements to assess their thyroid status, err on the side of caution, and limit their daily dose, as appropriate.” –


Naringin is a grapefruit derivative that enhances the effects of caffeine.


Additional Ingredients

When I write a review, I rarely mention the additional ingredients but, in the case of Synedrex, I have to make an exception. In addition to providing gelatin, which makes this supplement unsuitable for vegans and vegetarians, Synedrex also contains:

  • Talc
  • Calcium carbonate
  • Silicone dioxide
  • Magnesium stearate
  • FD&C Blue #1
  • FD&C Red #40

Calcium carbonate is okay. However, although all of the other additional ingredients currently have FDA approval, experts have raised concerns about some of them including talc, magnesium stearate, and FD&C Red #40.

I strongly suggest doing some research before using supplements that contain these ingredients. I have written an article that provides a good starting point: The “Other Ingredients” In Diet Pills.


Health Considerations

If you are pregnant or nursing a child, please don’t take any kind of supplement without getting clearance from your doctor first.

If you have an existing medical condition of any kind at all, it would also be unwise to use supplements without checking with your doctor first.

Certain supplement ingredients can present interaction issues when combined with medication. It doesn’t matter if the medication has been prescribed by a doctor, a dentist, or another medical professional. If you are taking medication, don’t use it with supplements without asking a doctor first.

*Information on the Diet Pill Ninja website is not intended to be a substitute for professional medical advice.


Customer Reviews

Some Synedrex customer reviews mention credible weight losses, improvements in energy, and also appetite suppression. However, other reviews say the pills did nothing at all and, not surprisingly given the stimulant-rich nature of this supplement, there are also reports of nasty side effects.

Here are few sample customer opinions:

Synedrex customer reviews and ratings


Known Side Effects

Nausea, headaches, racing heartbeat, anxiety… these are just some of the side effects customers have reported and it does not surprise me.

These symptoms are all typical reactions to stimulants and, by the manufacturer’s admission, this supplement contains a lot.

Please think twice before deciding to use Synedrex. Good results or side effects could come down to the luck of the draw and, of course, your stimulant tolerance.

If you do decide to use Synedrex, be smart about it. Seek expert medical advice first.

Where to Buy Synedrex Fat Burner

Synedrex is a pretty easy fat burner to get hold of. It’s available via many online stores. You can also buy Synedrex from the Metabolic Nutrition website. Regardless of where you buy it, the price is generally the same. At the time of this review, you could buy a bottle of Synedrex for $49.99.

Each bottle contains 60 capsules so, when you are using the maximum dose of 2 capsules per day, a bottle should be good for a month.


Metabolic Nutrition does not back any of its supplements with money-back guarantees.

Synedrex Fat Burner: Diet Pill Ninja Conclusion

The Diet Pill Ninja: Honorable Diet Pill ReviewsI began this review by admitting I am not impressed with Synedrex fat burner. Unless you skipped the section that evaluates the ingredients, by now you may understand why.

Synedrex provides several powerful stimulants. Worse still, the manufacturer does not reveal the inclusion rates.

The fact that the formulation contains a caffeine booster is a further cause for concern.

Synedrex Fat Burner also provides several ingredients that are unlikely to offer any value to the formulation and some of the non-active ingredients, though generally deemed safe, are controversial to say the least.

Grains of paradise is a good ingredient. But is there enough of it present? There is no way to know.

We do know that some customer reviews mention unpleasant side effects. That’s always a red flag.

I do not doubt that some people may be able to use this product without experiencing any negative issues, but it’s never a good idea to load up on stimulants. They are harsh on the body and even people who initially experience positive results during the early days of supplementation will probably find the benefits dwindle as their body becomes used to the extra stimulation.

A lot of things about this product worry me. I cannot recommend it, but I can suggest a better option and you may have heard of it. It’s called Phentaslim.

Phentaslim: A Good Alternative to Synedrex Fat Burner

Bottle Vegan-Friendly PhentaslimPhentaslim is a vegan-friendly thermogenic fat burner that has been around for quite a while. In addition to helping you to lose weight faster, it also boosts energy levels. So, although it’s very good at providing weight loss support, Phentaslim is an equally good option for people who want a fat burner that will also support improvements in their training/exercise routine.

Like Synedrex, Phentaslim has caffeine in it. It’s in the form of caffeine anhydrous but the manufacturer provides the inclusion rate. It’s only 270 mg. The formulation also provides a little caffeine from other sources but the overall caffeine content is not worryingly high.

It’s also important to be aware, that the Phentaslim ingredient profile lists the inclusion rates for the maximum dose of three capsules per day – that’s one capsule three times per day, not three capsules all at once. Each capsule probably provides around as much caffeine as a single cup of coffee.

Instead of additional stimulants, caffeine provides B vitamins. These increase vitality by helping your body extract energy from food.

The presence of ginseng supports further improvements in vitality and Phentaslim also provides generous doses of green tea and cayenne – two of the best natural fat burners in the world.

If you have an unusually low caffeine tolerance and have to avoid coffee, I suggest you avoid this supplement too. If you have no problems with caffeine at normal levels, Phentaslim is an excellent option to choose.

Not only does the manufacturer offer free shipping and a 60-day money-back guarantee; it offers some pretty sweet bulk-buy incentives as well, such as three bottles for the price of two or five bottles for the price of three.

Buy Phentaslim               Read My Phentaslim Review

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