Synedrex Reviews

Community Rating:

3.7 / 5.0

Editor's Rating:

3.7 / 5.0
By Derek Peterson
March 10, 2010

Synedrex is a fat-burning diet pill from Metabolic Nutrition said to combine natural ingredients to burn fat. With a 1-capsule dosage, manufacturers say Synedrex increases caloric expenditure, raises energy, enhances focus, and suppresses appetite.

The result?

According to Metabolic Nutrition, it’s “the most powerful one dose daily thermogenic.”

But everyone knows that outrageous advertising claims fool no one. Let’s dive below this glossy surface and see where the Synedrex current really takes us.

What’s in the Synedrex Formula?

According to Metabolic Nutrition, Synedrex’s weight loss benefits come from its 815 mg proprietary blend. This blend contains 13 natural ingredients that stimulate the central nervous system to increase metabolism and burn fat.

I’m not normally a fan of proprietary blends because they disguise real ingredient dosages, making it hard to tell if each ingredient is included in a safe and effective amount. But perhaps Metabolic Nutrition chose to list Synedrex ingredients in a proprietary blend to protect its formula from competitors.

Operating under that optimistic assumption, I’ll consider a few ingredients in this blend.


When the FDA banned ephedra, many diet pill companies turned to synephrine for its similar chemical structure and effect on fat burning. While anecdotal evidence supports synephrine’s effectiveness as a fat burner, it still causes side effects that may be too strong for many dieters. This is a big risk to take for an ingredient that remains largely untested [1].

Green Tea Extract

Like synephrine, green tea is a central nervous stimulant that sparks thermogenesis and burns fat. However, it is largely without synephrine’s potent side effects. When green tea is included in 300-600 mg doses, it triggers an average 30-pound weight loss [2]. Unfortunately, the proprietary blend in Synedrex prevents me from confirming green tea is present in its recommended dosage.


Another stimulant, yohimbine burns fat by creating heat and boosting metabolism. In 1991, test subjects in a scientific study lost an average 7.82 pounds while taking yohimbine [3]. Unfortunately, it too comes with unwanted side effects. It’s considered especially dangerous alongside caffeine, which may make green tea’s inclusion in Synedrex a bit precarious [4].

1, 3 Dimethylamylamine

1, 3 dimethylamylamine is a synthetic compound that progressed from a commonly-used nasal decongestant to a popular weight loss supplement. Although may say 1, 3 dimethylamylamine is a potent fat burner, its powerful side effects led to its FDA ban in 2012 [5].

Alpha Lipoic Acid (ALA)

Commonly used in skin care supplements, alpha lipoic acid is an antioxidant that prevents cell damage. According to a 2011 study, ALA also decreases body fat by treating diabetes and high blood pressure [6]. However, it would be nice to see a little more research on ALA before it’s fully embraced as a weight loss aid.

This ingredient profile is among the most potent I’ve seen. As a stimulant-based diet pill, Synedrex definitely succeeds. While I’m concerned about the lack of explicit information on ingredient dosage, the ingredients in Synedrex will likely provide weight loss for most users.

Unfortunately, the route to that weight loss may not be appealing. Many of these ingredients cause severe side effects that aren’t explored in Synedrex advertisements. I intend to explore them myself now.

Is Synedrex Safe?

Any time you rely on potent stimulants to help you lose weight, you’re going to experience side effects. Considering the Synedrex formula, I’d say the side effect possibility with this supplement is even higher than usual.

The biggest problem with the Synedrex formula is 1, 3 dimethylamylamine. This ingredient was banned by the FDA for a reason. According to WebMD, 1, 3 dimethylamylamine increases risk of heart attack and stroke by raising heartbeat and blood pressure [7]. The FDA banned the ingredient after several incidents of cardiac problems and even death were reported [5]. Clearly, this isn’t anything you want to mess around with.

Another problem ingredient is synephrine. While it’s marketed as a safe alternative to ephedrine, there’s not much safe about it for most people. Like 1,3 dimethylamylamine, it is linked to high blood pressure, increased heart rate, fainting, heart attack, and stroke.

Yohimbine often causes the same side effects and is considered especially dangerous when combined with caffeine, as it is here. In fact, many scientific researchers studying anxiety use the yohimbine and caffeine combination to induce the condition in test subjects [4].

With so many stimulants, I’m very worried about Synedrex’s safety profile. To see what it’s like for real customers, let’s take a look at some customer reviews.

What Do Customers Think?

Synedrex customer reviews on bear out my own conclusions: that Synedrex is an effective fat burner, but causes intense side effects. In fact, many of the 43 reviewers said they were “scared of” Synedrex, but found it difficult to argue with the resulting weight loss.

Here’s what a few such customers had to say about their weight loss experience with Synedrex.

“First sign, overwhelming energy. I just wanted to get up and do something! Then my body felt like it was heating up. About 2 hours in, I feel really dizzy and nauseous. I had to focus really hard to not vomit. When I got up and walked around, I had an overwhelming feeling of the room spinning. With the dramatic loss in appetite, I didn’t want to eat or drink either. This dizzy/nausea feeling lasted about 2 hours. After that, it was constant energy for another 6-8 hours. I’m quite frankly scared of these pills lol MAKE SURE YOU EAT! “—Chris Ace

“i was scared too! i had trouble sleeping last night when i took it at 10.” –Alexa

“It definatly suppressed my appetite, and within 5 days I had lost 5 pounds. Then into the second week, I was laying in bed, and my muscle in my leg started twitching… I was freaking out all night long…i would also get slight chest pangs, left arm and jaw…so I was nervous about that as well. Then I made the mistake of taking 2 one day as I was going to the gym and wanted some extra energy…. I stopped early on the eliptical when I realized my HR was almost 200. This is definatly not a supplement to mess around with….” –J.A. Larko “shoppin mommy”

“I took for first time at 6:00 Am with food. Made me extremely nauseated and vomiting. May be great product for some I guess I have a very sensitive system. I have jitters and feel very warm as others have reported. I took one capsule. I regularly workout, there is no way I can today.” –Loyc

As you can see, Synedrex is an effective diet pill that comes with a very high price—your health. Of course you’ll lose weight if you feel too sick to eat. The question is whether or not it’s worth it. Hopefully, your answer is no.

How Much Does Synedrex Cost?

On the official Metabolic Nutrition website, you can get a 45-day supply of Synedrex for $59.99. Manufacturers recommend you take 1 capsule a day, so each bottle lasts about a month and a half. However, Synedrex is currently listed as “out of stock” on

You can keep checking back, or order from websites like:
Price: $31.99
Price: $32.93
Price: $39.75

Advantage Supplements
Price: $44.99

Price: $44.99

This is a fairly average price for a diet pill. The deals on eBay and VitaDigest make it even better. However, the dangerous side effects associated with Synedrex make the benefits from a low price negligible.

Should You Try Synedrex?

Synedrex definitely contains some effective weight loss ingredients, but unless you think lying in bed and feeling nauseous is the ideal weight loss program, I don’t recommend it.

If you’re very tolerant of stimulants and have used a product like this in the past, you may like Synedrex. However, I don’t recommend gambling your health for the sake of fast weight loss.


[1] Haaz, S., K.R. Fontaine, G. Cutter, N. Limdi, S. Perumean-Chaney, and D.B. Allison. 2006. Citrus aurantium and synephrine alkaloids in the treatment of overweight and obesity: an update. Obesity Reviews: Vol. 7, Issue 1.

[2] Di Pierro, Francesco, Anna Borsetto Meghi, Angela Barreca, Maurizio Lucarelli, Andrea Calandrelli. 2009. GreenSelect Phytosome as an adjunct to a low-calorie diet for treatment of obesity: a clinical trial. Alternative Medicine Review: Vol. 14, Issue 2.

[3] Kuehne, Martin and Randy Muth. 1991. Total syntheses of yohimbe alkaloid, with stereoselection for the normal, allo, and 3-epiallo series, based on annelations of 4-methoxy-1,2-dihydropyridones. Journal of Organic Chemistry: Vol. 56, Issue 8.

[4] 2013. Yohimbe. bine+%28YOHIMBE%29&source=2.

[5] The U.S. Food and Drug Administration. April 2013. Stimulant Potentially Dangerous to Health, FDA Warns.

[6]Koh, E.H., W.J. Lee, E.H. Kim, E.H. Cho, E. Jeong, D.W. Kim, M.S. Kim, J.Y Park, K.G. Park, H.J. Lee, I.K. Lee, S. Lim, H.C. Jang, K.H. Lee, and K.U. Lee. 2011. Effects of alpha-lipoic acid on body weight in obese subjects. The American Journal of Medicine: Vol. 124, Issue 1.

[6] 2013. Dimethylamylamine.

User Submitted Reviews

16 out of 19 (84 %) Reviewers Recommend This Product

Community Rating:
3.7 / 5.0


Jessica | April 18, 2014

Forgot to add in my review: do not drink while taking this product.

I drank twice while taking synadrex and had severe depression and horrible thoughts the next day. It took me about 2-3 days to recover mentally despite having amazing & enjoyable nights. Do not drink while you are taking this.

Yes, I recommend this product

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Jessica | April 18, 2014

Started taking syna as a recommendation for my trainer to get ready for competition. At first I was terrified because on 2nd day my chest got tight my skin got itchy and I blew up like a lobster. It makes you feel like you are cracked out but once you get used to it it’s the most unreal focus & productivity ever. I’ve dropped at least 10 lbs with diet and training . I take it first thing in the morning followed shortly by bcaas . Lately in the last 3 days of my cycle if I eat too much too soon and don’t drink enough water I throw it all up. Redness and burning skin lasted throughout whole cycle but only for about 15 min. Great for energy & craving suppressant. You will have to choke down your meal 1 though . Didn’t have any trouble with sleeping. Took it at 8 am and usually burnt out by 9pm . Had pre workout at roughly 6pm and no adverse side effects except maybe red face. Don’t drink coffee within 3 hours of taking synadrex. Also take cla & alc 2x a day and didn’t have any problems. Will do a YouTube review. Best fat burner on the market in my opinion. I’ve had hydroxyl cut & various lines of lipo 6.

Yes, I recommend this product

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Mohamad | April 7, 2014

I have been using synadrex for one month and i get an amazing result , my weight was 86kg and my current weight is 77kg , i was worried about consuming this kind of fat burner for the first time but ill make a research to make sure that no side effect for synadrex. Synadrex give me big energy to continue my workout and my work days .

Yes, I recommend this product

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Alex | March 3, 2014

Started taking this three days ago. First symptom was my entire face seemed like it was on fire. It stopped within a half hr. I have no appetite and really makes you feel empty without being hungry. Definitely need to eat something with this. Sleeping is very different not as deep. Never tired? Definitely effects your sex drive as well as your erection . Will continue to use to see if symptoms decrease. Only using to loose 10 -15 lbs. haven’t worked out with it yet..will see.

Yes, I recommend this product

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Andrea | November 26, 2013

I’ve tried numerous fat burners and out of all of them, synedrex is my choice. I like the burst of energy and focus it gives.
I’m training for a competition which means I’m eating every 2-3 hours, and drinking plenty of water which i really think helps minimize the side effects. I think some people take it and go about they’re daily business without changing their diet much or training routine and thats why they get the bad side effects.
HERES THE CATCH. I have tried two times taking it first thing in the morning before i eat with plenty of water.. once i hit that 15 min mark whether i’ve started to eat or I’m just about to, i vomit. SO what i’ve tried is in the middle of my breakfast I take it and by the time i finish i feel great. I know its better to get it in on an empty stomach then consume your meal, but I still feel the positive effects which is why i continue to take it this way.
My body reacted terribly when I attempted to take clen, this seems to one step down from it which is why i like it. They also make synedrex in a stimulant free formula which could be an answer to those who are having a hard time with this particular formula.

Yes, I recommend this product

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DM | November 6, 2013

I have seen amazing results with this pill. 30yo. starting weight 136lbs. current weight 125. (5’2) I certainly do not starve myself but I am eating less. Has anyone experienced missed periods? I have for the last two months. I am going in for an exam today with my obgyn. My blood tests show I am not pregnant and am ovulating so I am curious if taking this pill is causing my irregularity. I can only take one pill daily as well, I do get nauseous after taking it, but that subsides after eating breakfast. I did experience bouts of feeling blue and headaches. Also it is sometimes hard to fall asleep. I’ve been trying for a while to get the weight off, through diet and exercise, with out results. I finally saw results with this pill and the side effects are worth the trade-off. But, I am concerned about the potential cause of my OB issue. please respond if you’ve had a similar experience. thank you.

Yes, I recommend this product

1 of 1 People Found This Review Helpful

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fit4me | October 23, 2013

I have been using Synedrex for almost a month. I have dropped 5 pounds and 3% body fat decrease with little change to an already clean diet. Effects I noticed, has been a feeling of heartburn and or indigestion. Not sure if anyone else has experienced this. The boost in energy, fat and weight loss is great, but worried about the heartburn/indigestion feeling which has never been a problem for me. I have stopped taking the pill for a few days to see if I can point the problem. Of course, my mind goes to paranoid feelings of making sure I am not experiencing heart attack symptoms with true indigestion.

Yes, I recommend this product

1 of 1 People Found This Review Helpful

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Katrina | October 8, 2013

I have been taking weight loss pills for a years now, and I needed an extra ‘kick’ to get me back to training. And Synedrex is definatley the best I have ever used. I was able to lose 10lbs. in a week (I juiced and went on the GM Diet.) I had no side effects except more energy and appetite suppressant. I am a female, 5′ 7″, 17years, and now I am 135lbs and plan to lose more. But be careful, because even though I never had any side effects, I know my friend was rushed to the ER because her body never had that much caffeine in her system. So just be aware. (My other friend did not have any side effects either). I strongly recommend this product to anyone who wants to lose weight fast. The price is up there, but seriously did you think an effective weight loss pill would be cheap? Anyway, I say try it, what do you have to lose?

Yes, I recommend this product

0 of 1 People Found This Review Helpful

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carlos | October 7, 2013

I’m 28 year I have been taking this product for the past 2weeks.I noticed I lost a totaL10 has it bad side effect you feel very panicky.very hard to fall asleep at night.I consider myself very sexually active i haven’t had problem having an erection.but since I’ve been taking this product I have lost my sexual drive.has anyone else experienced this.I honestly don’t recommend there’s no pill out there worth losing your sex life!

No, I do not recommend this product

1 of 1 People Found This Review Helpful

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Ashes | October 3, 2013

I’m 30. Average weight size. I’m not fat fat, but I’m not skinny ither. But I can lose a good 20lbs and be super happy!! My appetite is GONE ! I have no desire to eat. Dnt get any cravings of nothin! Which I guess is good cause I can snack all day and all nite. I force my self to eat 3times a day. No big meals, I’m not a healthy eater, but considering that I’m forcing myself to eat, I’ve made better choices( after all I DO wanna lose weight)
My sleep has also been bye bye. But I’m tired and I rest but I’m not sleepy. Which before this – I could sleep all day (no joke) if I’m off from work. Is this safe? I can’t say yes- but I can’t say no-
I’m going into my 4th day – eating habits defiantly changed !! I said no to jack in the box last nite !!! THATS A BIG THING FOR ME !!
I’m tring it out- I can feel like I’ve lost maybe 3lbs .. But I haven’t weighed so I can’t say exactly – but I see my naked body everyday.. I can see a slight slight change do far !

Yes, I recommend this product

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GG | September 20, 2013

I should start by saying, I have a very high tolerance to fat burners. I took the old version of OxyElite Pro well over a year to shed by baby weight, and I continued to drink coffee. I cycled off and wanted to try something new, and Synedrex seemed effective. I don’t sweat as much as on the Oxy, I think the appetite suppressant properties are about the same. I felt a touch blue the first day I took Synedrex, but that has gone away. It gives me energy, however I can feel my heart rate increase once I’ve taken it. I only take 1 pill a day, on an empty stomach about 7 AM. It has affected my sleep a little. I also feel a little nauseas about an hour after I take it, but that also goes away, nothing close to actually being sick. None of these products are good for you, and because of the stress it puts your body under, I never work out on it; I work out in the evenings. I think if you have a good tolerance to stimulants it will work for you, but listen to your body and drink a lot of water. Definitely cycle off when you’re supposed to or it will downgrade your adrenals too much. I think it’s an effective product, and will take the entire bottle. I would also consider giving your body a break on the weekends.

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Kyle | August 27, 2013

I have been taking Synedrex for over a month now and am coming close to ending my cycle of the drug. It is absolutely an effective weight-loss supplement, acting as a constant source of energy. It suppresses appetite for food almost entirely, allowing for a more controlled diet. In the month I have taken it I have lost over twenty pounds of fat, through little concerted effort.

It is not, however, free of complications as stated by the initial review. I have experienced severe anxiety and depression since I began taking it, as well as occasional feelings of dizziness. I should note that as a rule I am more resistant than the average person to stimulants. The bottle recommends that if you require a stronger dosage to take two in the AM, but I can’t possibly imagine someone that could safely do so.

I highly recommend this product if you care about results and feel you can take what it dishes out. It’s been a major source of stress but has accelerated my dieting and helped immensely in workouts.

Yes, I recommend this product

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