This product contains some dodgy ingredients, and is made by an even dodgier company. Should you trust a company that has multiple major errors on their own website? Check out our review for more:

This list has the best men’s products for better stamina, endurance, and libido.

Syntheroid Overview

Syntheroid is a supplement that’s aimed at men who want to increase the amount of testosterone in their bodies. This supposedly “scientific” formula is supposed to be better than the competition, and men who take it are supposed to see massive improvements in their workouts and in their sex lives.
Turns out not all of the claims made about this product are true, but that’s not all: the company that makes the product, XPI Supplements, LLC, has problems of their own. We’ll get into that in a moment.

Check out our list of the best stamina enhancement products for men.

Syntheroid Claims

Men who take this product are promised a world of difference: better stamina during workouts  and more energy to get through the day. Men are promised bigger muscles, since testosterone is supposed to have an effect on the physical growth of muscles after working them out. You’re also supposed to see fat burned off quicker than before, so men are promised a “shredded” body quicker than if they tried exercise and diet alone. Last but not least they promise that men are supposed to see improvements in their sex drive – another part of the body influenced by testosterone – and with a bigger libido, their love life is supposed to be hotter than ever before.

This product claims to be different from all the other testosterone-boosting supplements out there. The difference? They say it’s down to the fact that their ingredients are formulated in the “right amounts” – presumably in contrast to other supplements that have these ingredients in the wrong amounts? They don’t really go into detail about why their ingredient dosages are better than the competition, or what the exact differences in dosages are, which would have really helped their case.

The first major problem we noticed when looking at this product’s website is the fact that there are many references to a totally different product – Testosyn – where references to Syntheroid should be. Why? Turns out Testosyn is another product owned by XPI Supplements, LLC, and our first guess is that they simply copied and pasted previous text that “used” to refer to Testosyn and forgot to replace the name. Whoops! This is a glaring error, a mistake so obvious that only a child could make it. This really reflects badly on the company, and makes them look amateurish and incompetent.

It also implies that this product is so similar to Testosyn that they didn’t think to write new text describing it, implying that they’re basically the same product, which weakens the case for Syntheroid (and Testosyn!)

XPI Supplements, Inc, has another problem: terrible customer service. They have a “D” rating from the Better Business Bureau, and multiple customer complains have been put forward about how people either did not receive their orders after paying, or that they couldn’t get a refund after one of their products turned out to cause horrible stomach problems. Sounds like a fun company, huh?

Here’s a ranked list of the top male sexual supplements, based on effectiveness and quality.

Syntheroid Ingredients

Syntheroid has a standard list of herbal ingredients in its formula, all of which we’ve seen in many other supplements. Here’s a list:

• D-aspartic acid
• Fenugreek
• Tribulus Terrestris
• Horny Goat Weed
• Maca
• Eurycoma Longifolia
• Boron
• Bioperine

D-aspartic acid is a compound found in soy products that’s supposed to increase the amount of testosterone in the body by directly activating the parts of the brain that make it. It’s promoted by Syntheroid as one of the scientifically-proven ingredients that make it up. But when we started researching this ingredient, we found that Syntheroid has really overstated d-aspartic acid’s credentials, which we’ll cover in detail in the next section.

Lots of male fitness supplements use fenugreek as a way to increase testosterone activity, and it’s also a popular sex drive enhancer in the alternative medicine community, possibly due to its testosteronic effects.

Tribulus Terrestris, eurycoma longifolia and horny goat weed are all herbal aphrodisiacs, mainly from Asia, which are thought to have an effect on boosting the sex drive (mainly by increasing blood circulation and stimulating hormone regulation).

Maca is a natural plant from the Peruvian highlands which has been used as a medicinal treatment for a number of different symptoms,mostly having to do with hormone regulation. There are multiple types of maca, some of which are more beneficial than others. We’ll get into that more in a bit.

Boron is another ingredient we’ve seen a lot of the time in male enhancement supplements, but its use as a testosterone-booster is based on some shaky evidence. We’ll cover that in the next section.

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The Science Behind Syntheroid

Overall, it looks like the main ingredient that they’re pushing for is the d-aspartic acid. They list it first, they give it the acclaim of being scientifically-proven in clinical trials, and to be fair, it’s one of the only ingredients that’s actually been tested on humans. Unfortunately for Syntheroid, the findings of those trials doesn’t actually help their case. You see, there was a study conducted by Topo, et al (NIH) that showed a dramatic increase in testosterone in the subjects after taking a supplement containing d-aspartic acid. The problem? Those results were never seen again. In fact, in an overview of studies about d-aspartic acid, the researchers concluded that after reviewing all the studies that have been done, there’s no definitive answer to whether or not the substance works (Roshanzamir, Safavi, 2024). So much for scientific proof!

Boron is a mineral commonly used in men’s health supplements, because one or two trials showed some increase in testosterone, such as those performed by Nielsen, Hunt et al, and Naghii, Mofid, et al – but that’s it (NIH). Like d-aspartic acid, more trials need to be conducted, because right now the evidence isn’t convincing enough (Examine.com).

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Word on the Street about Syntheroid

There are six “Testimonials” on the Syntheroid website, but the problem with these is that they were specifically selected by the company, and so how do we have any assurance that they’re fair and impartial? We also don’t know how the average person is going to react to it, or if it will work for a large percentage of people, which is why we need to see large amounts of customer reviews, good and bad, to see if this product is worth it. We checked Amazon for this, and oh boy, the results aren’t good.

In fact, the majority of people who reviewed this product gave it only 1 or 2 stars out of 5 – which is dismal:

“I even went to a lab to test my testosterone levels after taking this, and there was no increase. It’s a placebo.”

“This gave me more energy than I had before! I’m recovering quicker from my workouts.”

“I wasn’t able to get my money back, since I tried it for thirty days to make sure it worked – it didn’t, and the 30 day refund deadline passed.”

“This is a good product!! Many improvements.”

“I tried this for 30 days and saw no improvements at all.”

“Didn’t do anything for me, even after using it for a month.”

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Is Syntheroid Worth a Try?

Although there are a couple decent ingredients in this product, we don’t know what their quality or purity is, and they’re dragged down by other ingredients like boron and d-aspartic acid which have no proof that they work, according to clinical studies. The company that makes this product has a terrible customer service reputation, and the majority of customers that we’ve seen review this supplement found that it didn’t work. What does that tell you? It says “Avoid at all costs!”

Seriously, there are lots of testosterone supplements out there, and with all the flack this company has gotten and the bad customer response Syntheroid has received, there’s no reason to waste your money on it.

Click here for a Top 10 list of supplements that can improve male performance and stamina.

Syntheroid vs Testosyn

As we mentioned above, these products are both from XPI Supplements, and are so interchangeable to them that they forgot to delete Testosyn’s name from the official Syntheroid website! The only real difference we saw between these two products is their name. The formulae for these two supplements is nearly identical except that Testosyn included vitamin D and zinc in the mix. Their prices are the same ($59.99 for a one-month supply), and both sites offer 10% off by signing up for an email list. One weird difference is the money-back guarantee: Syntheroid’s is 90 days, while Testosyn’s is only 60 days. Since they’re the same company (and practically the same product) why make one have a longer refund period than the other? Very strange, and this whole situation may end up being confusing for some customers.

Syntheroid vs Testofuel

Both of these claim to increase the amount of testosterone in your body, and through natural ingredients instead of drugs. One thing Testofuel has going for it that Syntheroid doesn’t is polish: the overall website packs more information into it than Syntheroid, and in a more attractive way.
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Testofuel and Syntheroid are both based on the supposed actions of d-aspartic acid, but if you’ve read our review, that doesn’t necessarily bode well for either of them. Testofuel contains oyster extract and vitamin D, which aren’t included in Syntheroid, and seems to be made in GMP-qualified facilities, meaning they meet standards and regulations for quality, while Syntheroid doesn’t.

Syntheroid vs Nugenix

Nugenix, unlike Syntheroid, focuses itself mainly as a supplement for men over 50, as they make heavy references to this fact on the website. They both concentrate on raising testosterone with herbal extracts and natural ingredients, and both make use of fenugreek. Overall, Syntheroid contains more ingredients than Nugenix, mostly in the form of all the aphrodisiacs it has. They’re both around the same price, at $59.95 and $57.99 respectively. Nugenix offers a “free trial” but the catch is that you have to sign up for an auto-ship program that will charge your card for the full amount if you don’t cancel in time.
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This has gotten them into some trouble with the Better Business Bureau, as can be read on the BBB profile page for Nugenix. They’ve also been charged by the BBB for not fully supporting the claims made about the supplement. Overall, it looks like both products are equally in trouble with customers, based on their BBB profiles, but for different reasons altogether.

Syntheroid FAQ

1. Is Syntheroid available at GNC?
   No, it looks like you can only buy the product from its own website and from Amazon.
2. What are Syntheroid’s side effects?
   No side effects are listed for Syntheroid, so you would have to go based on the possible side effects of the individual ingredients in the formula.
3. Where can I read Syntheroid reviews?
   We were only able to find reviews for this product in two places: the company website and Amazon.
4. What are the ingredients for Syntheroid?
   D-aspartic acid, Fenugreek, Tribulus Terrestris, Horny Goat Weed, Maca, Eurycoma Longifolia, Boron, and Bioperine.
5. Does Syntheroid work?
   Based on what the majority of customers have said on places like Amazon, it doesn’t look like it works very well, although it may boost energy for some people.
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6. Is Syntheroid different from Testosyn?
   There are minor differences between these two products, mainly having to do with the inclusion of vitamin D and zinc for Testosyn.
7. Are there any drug interactions with Syntheroid?
   Yes, this product may interact with some medications. Speak to a medical professional if you have questions about particular interactions.
8. Is Syntheroid a medication?
   No, Syntheroid is a nutritional supplement, which means that it’s available without a prescription – although at the same time the company cannot legally claim that it treats any medical condition or has confirmed results.
9. Is Syntheroid a good testosterone booster?
   Based on the customer reviews we’ve read, it doesn’t look like this product is very effective as a testosterone booster.
10. Who makes Syntheroid?
    Syntheroid is made by XPI Supplements, Inc, a supplement company based out of Utah.

Here is our list of the finest products for improving energy – and libido – in men.

So What Really Works?

So you’ve seen what happens with supplements that don’t work: poor reviews, weird and untested ingredients, and a disappointing and untrustworthy company. That’s why, when people ask us “what’s the best testosterone supplement,” we tell them to try Viritenz. It’s the best male enhancement product on the market, as far as we’ve seen. Its formula of all-natural ingredients can help men with their energy levels and stamina, as well as help them get stronger erections, and have a better love life. It’s made in the USA in an FDA-monitored facility, so you know it’s going to be pure and untainted, and it also comes with a money-back guarantee.

Not all men have the same drive that others do (including sex drive), and that could be due to age, or lifestyle, or genetics. The good news is that there’s a way to change things around, and Viritenz could be the answer. Click here to read more about Viritenz, and about how it can help you to achieve the active life you’ve always wanted.