Update 3/17/21. When I first heard the name Syntheroid I thought it was a supplement for the thyroid because its name sounds a LOT like the drug synthroid that people take for hypothyroidism. But Syntheroid is billed as a natural testosterone booster whose motto is “power, mass, sexual performance.” The makers of Syntheroid claim that it can improve speed, agility, and reaction time, as well as muscle size and strength. This is in addition to the claim that Syntheroid can maintain libido during hardcore dieting. These are all pretty bold statements so I'm not surprised if people wonder if Syntheroid really works or not? Let's now review Syntheriod and what can be discovered. Also see my review of the HGH supplement, SeroVital.
Who Makes Syntheroid?
When I checked the product website – syntheroid.com -I couldn't find out who makes this product. It's only after some digging that I discovered that syntheroid is made by a company called XPI (xpisupplements.com).
The address of XPI labs is 965 N 1430 W Orem, UT 84097. The link provided is to show what the area looks like. I see a lot of warehouses. I did not see any building called “XPI laboratories” but since most of the buildings appeared dull looking – built for function, rather than looks – I'm sure it's in there somewhere. XPI labs do not seem to have a BBB listing when I checked on 12/7/11.
On the Syntheroid.com website, there is a video of a 31-year-old man named Josh Dahl (“The Josh Dahl Story”) where he says that Syntheroid makes him feel like he's 21 years old again. They listed his name like we should know who Josh Dahl was – which I didn't – so I did some goggling on who Josh Dahl, was but could not find anything. Maybe Syntheroid did do what Josh said but in general, I take all testimonials from people I do not know with a big grain of salt.
Syntheroid Ingredients
Kudos to the Syntheroid website because they do tell us what's in this product. If you take 3 capsules of Syntheroid -the recommended dose – you get the following:
Tribulus Terrestris | 650 mg |
Testofen | 300 mg |
Aminogen | 250 mg |
Coleus forskohlii | 125 mg |
Milk Thistle | 120 mg |
Alpha lipoic acid | 100 mg |
Eurycoma Longifolia | 100 mg |
Horny goat weed | 100 mg |
Bioperine | 15 mg |
Remember, even though the name syntheroid sounds like a drug, syntheroid is not a hormone or a pro hormone. It's a dietary supplement. They even say this on the Syntheroid website.
Looking over this list of ingredients, Syntheroid has some things found in many other products I've reviewed in the past.
For example, Syntheroid has Tribulus. I know people have said that tribulus works for them but I have been skeptical about the claims of this herb since the 1990s when it first started getting popular. For more on this, read the Tribulus review.
Despite the hype about Tribulus and testosterone, I can't find any proof that it works. For example, in a study published in 2001, Tribulus didn't work. In another study from 2007 tribulus didn't work.
If anybody knows of a“tribulus raises testosterone study”, please let me know and I will happily update my reviews on this herb.
Now, no study is perfect, so if you really want to know if tribulus raises testosterone, get your doctor to check your testosterone before starting tribulus (or Syntheroid) and after a month of using it. This is the only way you can know for sure if it worked or not.
As for Testofen, it's a cool-sounding name and was likely invented to give the impression that it raises testosterone – but it doesn't. Testofen is just a made-up name for the herb Fenugreek. For more on fenugreek- testosterone research also see the review of Ageless Male.
Fenugreek might raise insulin levels. Since insulin helps us use amino acids, that means it has a mild anabolic effect. I'm guessing this is why it's in a testosterone booster supplement. Here is Fenugreek on Amazon.
Ironically, this effect on insulin is why fenugreek is also found in diabetes supplements. For example, the diabetes supplement Glucotor V2 also has fenugreek. In fact, this diabetes supplement has the same amount of fenugreek – 300 mg – as Syntheroid does.
Aminogen
The Syntheroid website says that Aminogen is a ” proprietary proteolytic synthetic enzyme” that “was created to improve protein digestion and absorption.” That means at that Aminogen is not an amino acid supplement but rather just a fancy name for a protein-digesting enzyme supplement.
Unless you have a problem absorbing protein you don't need enzyme supplements. They say that Aminogen “works to produce a higher bioavailability within your body, particularly to your muscles.” So, where is the proof of this? As far as I can tell neither Aminogen – or Syntheoid – has any peer-reviewed clinical proof that it does anything. Since they can't prove to me that this statement is true, I discount it.
Just a heads-up, animal protein – has a very high absorbability, so unless your doctor has told you that you have a problem with digestion, you don't need any supplemental digestive enzymes. What's a good way to remember animal protein? It's any food that had a mother. That's how I remember it!
Coleus Forskohlii
This herb is said to be a metabolism booster and weight loss supplement. The idea here is that coleus forskohlii (forskolin) stimulates fat-burning enzymes that help us lose weight. One small study of older, overweight men also noted that coleus forskohlii increased testosterone levels.
This is the logic why Coleus forskohlii is found in many weight loss products such as Lean and Fab and Apidexin to name a few.
Here is coleus forskohlii on Amazon.
The problem with coleus forskohlii research is that they often have problems and so for the moment, I will keep an open mind about forskolin until better research is done. For more on this research, read my Coleus forskohlii review.
Milk Thistle
Since steroid abuse is thought to damage the liver, and since Syntheriod is reputed to be a testosterone booster, I'm guessing this is why they added the liver-protecting supplement -milk thistle – to Syntheriod.
That is the most obvious answer I can guess because there seems to be no clinical proof that milk thistle raises testosterone or improves libido. There is interest in milk thistle for diabetes because it has been shown to reduce blood sugar levels.
Might stabilizing blood sugar levels help people have better workouts? In theory, maybe. This might be another reason for putting milk thistle in Syntheroid.
Mostly this herb is an antioxidant and one of its active ingredients is a compound called Silymarin. Syntheroid has 120 mg of milk thistle but I can't tell from the product website how much Silymarin this translates into.
Alpha Lipoic Acid
Like milk thistle, alpha-lipoic acid has also been researched for its blood sugar-lowering effects. I've seen this stuff used in many exercises and weight loss supplements despite any good proof it helps weight loss or exercise.
For example, alpha-lipoic acid is also found in the bodybuilding supplement Stemulite and Jillian Michaels Fat Burner as well as the Plexus Slim weight loss supplement.
Like several other ingredients in Syntheroid, eurycoma longifolia is found in a variety of other products. For example, this herb is one of the main ingredients in TriVerex – a male enhancement product you may have seen on late-night TV.
It's probably eurycoma longfolia – as well as horny goat weed – that is at the heart of the claims that Syntheroid improves sex. I don't want to reinvent the wheel on these ingredients, so please read my words on TriVerex” for more info on the research behind both Eurycoma longfolia and horny goat weed.
The same thing goes for Bioperine. For more on this ingredient see my Lean and Fab review.
Syntheroid Side Effects
I think if you are healthy you might not notice any side effects with Syntheroid. If you are not “healthy” or take any medications, see your doctor first. Syntheroid is probably very safe in healthy people but as far as I can tell this assumption has never been tested. Here is Synteroid on Amazon for those who want to check out the comments from others who have used it.
One older study noted that alpha lipoic acid might lower thyroid hormone levels. If this holds true, it might also reduce vitamin D levels as well as metabolic rate. I'm not sure if this “side effect” is true or not but it's worth mentioning just in case you have hypothyroidism. Alpha-lipoic acid might also add to the effects of insulin and other diabetes drugs.
Fenugreek might cause hypoglycemia (low blood sugar) and interact with insulin or other blood sugar-lowering medications. It might have an even greater blood sugar lowering effect when combined with alpha-lipoic acid.
Milk thistle might interact with many medications like coumadin (a blood thinner). The herb might also have an estrogen effect that might be bad for women with a history of breast cancer. This effect is probably a long shot, but speak to your doctor if you are not “healthy” just to be safe.
How Much Does Syntheroid Cost?
They say 1 bottle currently costs $59.95 on the Syntheroid website. I think that is a lot of money for a product that has zero clinical proof that it works.
Here is Synteroid on Amazon to compare prices.
Does Syntheroid Work?
On the XPI labs website, they say that Syntheroid “was scientifically formulated to boost testosterone levels, improve protein synthesis, absorb nutrients, and burn fat faster than any other legal supplement on the market.” Scientifically formulated? How did they scientifically formulate this product but did not conduct any scientific tests to prove Syntheroid actually does what they say?
In my book, you can't invoke the name of the mighty god science (lowercase g) without doing actual scientific testing – in humans. Failure to do so is just bad science. They also say that with Syntheroid, you can boost testosterone by up to 400% but proof of this cannot be located.
If you are interested here is Synteroid on Amazon.
Hiraikami says
I do not know about you guys, but I have been taking SYNTHEOID for only one day now and already I can tell a difference… At times during the day I’m usually unfocused and not feeling all that great. Now, I feel more focused and allot better as if I have more energy.
Like the feeling of raised testosterone IMO. That feeling of what I can only describe as Pure strength running through your veins that also gives you that unparalleled focus. I know it sound too good to be true, but those guys at XPI have something here.
Now I am not saying it will work the same for everyone or there will not be any side effects. I am just describing my experience of this product after only a day of taking it…
Christian says
Wow, I commend the author for being so patient with some of the readers. Hate to break this to all you body dysmorphic sufferers out there (yes body building is a mental condition like it or not) but the only testosterone booster out there for a healthy, well versed men in S&C nutrition and the like is synthetic testosterone.
Tribulus is one of the best hyped snake skin oils of all time. Learn the value of interpreting sound research and you’ll be better equipped to distinguish between note worthy supplements and well developed marketing campaigns.
sam says
Hey Joe,
Thanks for all the work you do reviewing all the different claims these products make. It’s really impressive! I too have been hoping to find a t-booster, but haven’t found any good peer reviewed research on the different products out there. I was wondering if you saw this abstract from the British Journal of Sports Medicine: http://bjsm.bmj.com/content/37/5/464.full?sid=8696c851-0aba-4e70-b503-aa5be3034329 I have no idea if this is any kind of top tier journal in it’s field, and I was also not able to find more than just the abstract. Definitely the small sample size is a weakness in the study, but it seems like it might be worth looking closer at Eurycoma Longifolia. If this is a legit study, and with the other studies on mice, it could be a possible natural t-booster. It seems like it would be so easy to do a clinical study with pre and post testosterone level checks and this herb. Any thoughts on the abstract?
Just as an aside, you mentioned in a different review that placebo groups should have no effect. I don’t think that is necessarily true. Placebo groups will very often have effects because of the self fulfilling prophecy–which is also why many people are experiencing positive effects with these different products. It’s okay if there are significant effects in the placebo group, but are the effects in the treatment group significantly greater than the effects in the placebo group. I’m open to being wrong–it’s been over 10 years since graduate school.
Joe says
Sam, yes i agree there may be an effect from the placebo effect. In a perfect world it should do nothing but the placebo effect is a real phenomenon. I should have said no significant effect.
The British Journal of Sports Medicine is a respected publication. i did notice that the study – THE ERGOGENIC EFFECTS OF EURYCOMA LONGIFOLIA JACK: A PILOT STUDY – is a “pilot” study, meaning its a “beginner study”. they did not specify what extract of Eurycoma longifolia Jack they used (they just said “water soluble extract”) so Id like to know that.
there were only a few people in this study but I am looking forward to a larger study on this by the same researchers. thats what usually happens when pilot studies get good / interesting results.
Bobby says
I love trying supplements and seeing for myself the results if any.
I really would not give this product a try because IMHO it is too weak.
Tests of these products are normally done on Mice.
So if they use 100mg on a mouse and get results how many mg’s will a Human Being have to consume to get the same results?
You can hold a Mouse in the palm of your hand, so for example how many mice would it take to make a 80kg person?
IMHO – Weigh the mouse that takes 100mg of Tribulus and then mulitiply for a 80kg person and then we may see some results 😉
Rob says
Have you checked out the primordial performance website? The have all kinds of scientific research and case reports on the site. Their test boosters might even make more sense to you scientifically at least.
Joe says
Rob, I have not heard of that website before. Ill try to take a look at it
mike says
Ok thank you. Im sure I wil lbe back soon with more questions.
mike says
Thank you Joe.
And just one more question… I always hear that creatine messes with your ligaments or something. I hear that if you take it, you have a batter chance of hurting your ACL. I personally have friends that tell me it hurt there knees when they took it, even when they drank a lot of water. Is this information true and would you recommend maybe taking something like that?
Joe says
Hi Mike, I’ve read a lot of creatine studies over the years and Ive never seen one study where creatine caused any injuries. People do tell me “I took creatine and X happened” but no studies seem to show it. That said, I do think I know what is happening with creatine and injuries. Remember, earlier I said that the loading phase starts to work in a week (while the maintenance phase takes about a month usually). Muscles start to get more powerful in a week – but the ligaments and tendons dont. I think people accidentally injure themselves by doing too much too soon. I’ve written about this see my creatine and injuries post
There you can also check out my post on “do I need to cycle creatine” another big question people ask a lot about.
mike says
Our school has a specific weight training program for the football players that is basically mandatory so I pretty much have to stick with that workout program.
I am not on a specific protein supplement yet. As of right now i just pick up a protein bar on the way home from working out, around 15-30g of protein.
Although it may not be a great idea, because my testosterone is already high, I am really fixated on taking some sort of booster. I feel stuck at the same weight while i see everyone pacing me. I am still worried about the chemical composition in my body. When i look up side effects all i see is oily skin and acne. I want to know how this is going to effect me long term. Will it change my personality? Or could it possibly lower my grades? I am more worried about these things than oily skin.
Joe says
mike, Im glad you are thinking about these sorts of things. I just dont know what they will do if you take them. One thing is I doubt most of them will raise your testosterone levels. I could be wrong but one thing that jumps out at me is that the websites for a lot of these products never show me any proof that they actually raises testosterone levels in humans. The wording used on some websites ect. leads us to that conclusion but where is the proof?
Are you still growing? If you think you are, consider that one side effect of testosterone is that it stops the growth of bones. Again, I dont think this means that T boosters would stunt your growth, because I’m not convinced they really work. Just something to point out.
Have you spoken to your coach about this? Maybe he sees something that you dont or can offer some advice? Does your school have a dietitian? If yes speak to her/him and see if they can look at what your eating and see if that helps.
mike says
i have also been doing LOADS of research and every different produce i look at all say the same thing…
“This is the strongest natural testosterone booster available”
mike says
Thanks Joe. i am a 18 year old student and my last year of high school football is coming up so I have been thinking of taking something to give me a little bit of an advantage. I am 1 of 2 captains on the team and the other captain is taking P6 along with other things. i am currently taking Fish Oli, Glutamine, and some simple proteins.
Although i am taking these im am still behind compared to the other retuning starters. I really think a testosterone booster would help a lot because i am a running-back and safety and i can use the exra mass and strength. The only problem is that i dont want to mess up my body’s natural chemical composition since i am still maturing. Any advice or recommendations?
Joe says
Mike, I dont think you need a testosterone booster because your levels are already super high right now. If you can do get your T levels checked by your doctor. I say this because knowing your testosterone levels now will help your doctor 30 years from n ow determine what might be a good level for you. So many men – me too – never got testosterone levels checked when we were younger so now when the doctor measures them and they say “your normal” I say “thats great but I dont know what it was when I was younger so I have nothing to compare it to.”
How much protein are you taking. since you are working out, as a rule you should be getting 0.6-.09 grams per pound. knowing this may help you add some muscle. Also remember the carbs are important also for getting stronger. If you do one day decide to try creatine supplements, you only need the maintenance phase of about 3 grams per day (the loading phase starts to work in a week but save money and just use the maintenance phase. it takes a month to kick in but it works just as well).
When you say you are behind others, I wonder if improvements can be made by working with somebody who has knowledge about sports specific training. Meeting a few times with a fitness trainer who knows about these training may help your game. Do a good search for your area and “football training” or “sports specific training”. Im sure of the cost but I dont think it would be more than your paying for a month of supplements.
Also be aware that some supplements are banned by the US Anti Doping Agency. Some of them are available in health food stores. If you go to college and play football ect. you should look at the list of supplements that are banned here is the website http://www.usada.org/supplement411
I hope some of this helps Mike
mike says
Have you done anything on Tribulus 1000.
Joe says
Mike, not that specific tribulus product but I have written 2 reviews on tribulus itself. Here is main review
http://supplementclarity.com/tribulus-terrestris-review-testosterone/
John says
I have ordered 3 bottles of this product, already have used half through without seeing any improvements, I guess doesn’t work! I would agree with the reviewer, just another product out there, without any scientific back up, and without any benefit to the users, lets just be honest. I am gonna try to see if they will honor there statement about 90 days money back guarantee. I would appreciate if anyone found any good, genuine testosterone booster out there, and post it here.
Nick Cooper says
hey guys i just started taking a pre workout called Force factor, and i also started taking Amplified mass xxx have you guys heard anything on these products? and also i would like to know how to take it im trying to put on weight for football im currently 5-10 160 and would like to get up into the 180’s and reccomendation? and also i would like to get my maxes up for lifting
Bench – 195 Dead Lift – 275
Squat – 365 power Clean – 185 Help please
Joe says
Nick, Here is my review of Force Factor http://supplementclarity.com/force-factor-the-facts-you-need-to-know/
I’ve never heard of Amplified Mass XXX
Kyle says
Hi there, i have ordered four bottles of Syntheroid but it has been siezed by Australian Border Protection. In the letter they sent me, they said it was prohibited unless a permission to import the goods has been granted.
What do i do? Also Bach i saw you got some from the US to AUS, how did that happen?
Any help would be great! Thanks
Brian says
Ia am on my 3rd bottle of syntheroid and it absolutely works. The sides are steroid like. The acne, sex drive and growth. I do agree about the price and the customer service is horrible but i am scared to change to another product because i dont know if anything out there is as good. If anyone knows of another good test booster please let me know. Thanks guys
John says
Just purchased Syntheroid after finding it the best natural t booster reviewed. 4 Bottles is supposed to be a 4 month supply, there is only 90 and you are expected to take 9 a day. That is a 40 day supply, so that right there is shady. I bought t booster before and it had 180 for twice a day, month supply. $160 for 4 months is good, for 40 days its a horrible deal. Just thought i would give the heads up of this over priced product. They say its normal $100 bottle that would be $100 every 10 days, GET REAL
Erik says
Thanks for the feedback Joe.
Unfortunately, I don’t know what my T levels were when I was younger- This was the first time I ever had it tested (perhaps it was always in a similar range for all I know).
Yes, I was thinking it couldn’t hurt to try something and then get it tested again after 30 days of use.
I’ll post what the results are.
BTW, thanks for the bit of reassurance that 387 isn’t so low. Maybe I’m worried about nothing. Other than the bit of muscle loss (heck, I can’t expect to have the same body at 45 that I did at 25) I feel just fine. Still, I’d like to see if I can get more out of my workouts and diet by raising my T levels a bit- if that is possible.
Joe says
Erik, anytime. glad to help 🙂
Erik says
Hi Joe.
Thank you very much for your valuable site. I’m obviously not the only one that appreciates what you do.
I am a very healthy 45-year-old with an excellent diet and workout regimen. However, I recently have noticed a drop in muscle mass which I couldn’t account for other than age catching up with me.
I just had a full physical including blood work. My LDL cholesterol was a bit high at 127. This is extraordinary considering how healthy my diet is. My ng/dl testosterone was 387 and my free testosterone was 8.7. These seem low to me.
I mentioned my cholesterol because I have read that when your testosterone drops it can cause other changes in your body such as raising cholesterol- Given my diet and exercise I have to think this is what is going on with me.
BTW, I should mention I have already been doing for years just about everything you can do to raise T levels naturally (lifting heavy weights/low reps, getting adequate rest, eating plenty of lean meats, vegetables, healthy fats, no alcohol, and on and on).
I simply don’t know what else I could do other than getting some supplementation help.
Long story short- Is there ANYTHING you would recommend in terms of a supplement to help with T levels?
Thank you very miuch in advance for any feedback.
Joe says
Hi Erik, I dont think 387 is “low” but do you know what it was when you were younger? I dont have a lot of faith in any T booster supplements because none of them have proven to me they do what they say. Some people have said they felt better after taking D Aspartic Acid but I’m not sure if it works either. Best advice is since you know your T levels now, try something for a month and then test T levels again. That is really the only way to know for sure if it works.
Tim says
I tried Syntheroid. I was on it 15 days. I read all the hype and positive reviews. I don’t have much faith in t boosters. This one WORKS! I felt it in about a week. Recovery and strength went up. Didn’t weigh myself. Felt that up libido. Aggression pumps it was all there. Oily skin all the obvious signs of elevated test levels. I ran out as it is a lil pricey and could afford more till next payday. Works fast. I was totally surprised and pleased.
Ray says
Hello, lots of interesting comments here.
Hey, those of you looking to increase your levels of testosterone, why don’t you just go see your Dr., ask him/her to do a simple blood test that will tell you if you need to increase your levels and do so under a Doctor’s advice and monitoring?
I don’t understand why anyone would trust some wishy washy Company instead of real medical advice for something that can be so damaging as taking crap that will affect your metabolism.
I guess it is true that there is a sucker (thousands) born every day.