• Positive

    • Contains 2 or 3 good T boosters
    • No proprietary blends
    • May help libido
  • Negative

    • Good ongredients under dosed
    • Missing key components
    • A few ineffective choices
    • Expensive considering the formula
  • Ingredients :
  • Price :
  • Trust :
  • Testimonials :
  • Company :
  • Overall Score: 5.8/10

You’ll find that most guys who use natural test boosters do so because they’re just that … natural.

Users like to steer well clear of the risks that come with lab built hormone. They’re just looking for a little support for the real thing. That’s why Syntheroid, from XPI Supplements, feels like a weird marketing choice to us.


It’s like a vegetarian food company busting out with a new nut loaf called Meaty McBeef or something, isn’t it? I mean, not sure you’re really playing to your audience with this one folks.

Then again, there are those who still like to believe you can get combine the power of a lab and the safety of mother nature, so likely that’s who this is aimed at. It promises to increase strength and muscle, fuel your libido and help cut unwanted body fat.

But as any who’s tried non-alcoholic beer, or is called George Clooney but isn’t that George Clooney, will tell you – it’s about more than just the name.

So how close to the ultimate hybrid does Sytheroid come. Let’s check it out.

How Does It Work?

At a Glance

  • D-Aspartic Acid to raise T
  • Fenugreek to balance blood sugars
  • Boron to both increase male hormone and lower estrogen
  • Maca root, Eurycoma Longfolia & Horny Goat Weed for libido.
  • Tribulus Terrestris to supposedly also boost testosterone

Let’s cover the score in some important areas first, before we get down to the real (or fake) nitty gritty.

The Scores


Syntheroid isn’t without highlights, there’s just not that many of them. It’s great to see D-Aspartic Acid at the top of the bill, though the dose falls short.

Fenugreek is given a solid amount though and that will benefit you in a couple of ways. Eurycoma longfolia, maca root and horny goat weed aren’t necessarily useless, but they are only going to help your sex drive and not much else. They are not strictly t boosters.


Another reason a lot of guys decide on natural boosters is they’re much cheaper than any synthetic option. Apparently because Syntheroid has the word Synth in it, they feel they can ask for a pretty high price.

That might work for Depeche Mode tours, but not this booster. The $50 isn’t the highest you’ll see but is right in the ballpark of some of the best T boosters around. Basically if you’ve got that kind of cash, there are much better ways to use it.


Let’s start with the positives – no proprietary blends. We get all the ingredients and their dosages. And there are and no complete dud ingredients apart from trib.

But the formula could definitely be much stronger, so pitching this as the most effective natural option feels naughty. Also the website is very quick to say the recipe is scientifically formulated, but they provide no evidence of tests. Seems to us the only science at work here is the unholy science of marketing.


There are a few testimonials on the XPI website, with before and after pictures as well as written statements.

That’s good to see because a lot of brands just let retail site feedback reviews do the talking. However these testimonials are not as extensive or convincing as some of the better ones we’ve seen. Especially since outside of the official site, on Amazon, reviews have been so mixed.

Around 30% are 5 star but around the same are 1 star claiming it does nothing. Not exactly a confidence fest.


XPI Supplements are a company operating out of Utah for over 5 years. They have a range of supplements including pre workout, weight management, protein, and T boosters. They offer 100% money back guarantee and have a live chat on the website for questions. They currently have a D- rating on Better Business Bureau site though based on 13 customer complaints and 1 being left unresolved.

How Do I Take It?

Users should take 2 servings of 3 capsules a day.

That may sound a lot but in actual fact it’s not ideal. It’s not really about the size of servings – although knocking a fistful back might feel like your giving your body what it needs – it’s about the frequency.

3 or 4 servings a day for example will make sure active ingredients are always topped up and working at their peak. Just 2 means that there will be points in the day when you experience a drop in effectiveness.

A poor serving schedule can trip up even some of the T boosters … and Syntheroid.

Any Syntheroid Side Effects?

They were aiming to produce a steroid with no side effects and they look to have nailed at least the second part of that at least.

Fenugreek can cause stomach upsets on some very rare cases, but not at the dosages in this formula. Generally the only thing Sytheroid will harm is your bank balance and if you didn’t know any better, your faith in natural t boosters.

Where Can I Get Syntheroid?

Customers will find Syntheroid on Amazon.com for $54.95 which will keep you going for a month.

Ingredients – In Detail


D-Aspartic Acid

D-AA is one of the best amino acids for T production. It’s one of the first things you should look for in a booster because it promotes 3 important building blocks of male hormone. Growth hormone, folicle stimulating hormone and luteinizing hormone all rely on it,

The next thing you should check though, is the amoumt as only doses north of 3000mg are going to get T pumping. Syntheroid can only manage half of that, which is really disappointing.




Fenugreek is a strong choice for a couple of reasons. It’s a real multi-tasker. It helps your libido and stimulates important androgens for T, but also helps to balance blood sugars.

Balanced blood sugars mean regulated insulin which in turn means T production isn’t interrupted. 300mg is a good amount too.


Tribulus Terrestris


Syntheroid assure us that their formula is scientifically proven but we doubt that. If they were really on top of what works and what doesn’t Trib wouldn’t get a look in.

Clinical trials have long since disproved that Tribulus Terrestris does anything to help testosterone. It may raise libido , but as we’ll see we don’t need that here. Any amount is too much but 300mg is way too much.


Eurycoma Longfolia

Sometimes called Longjack, studies show this might play a role in raising testosterone back to normal range if you have clinically low T, but beyond that it’s not much help. May assist in improving libido.




Again, not effective at boosting testosterone, but it has been used in traditional medicine to put you in the mood for loving so it might come in handy in that respect.


Horny Goat Weed

We’re starting to get de ja vu. Possibly good for your love life as some research shows it could aid men with erectile problems, but won’t make a dent on your T.




Boron is difficult to get enough of in the diet. Which is a pity, as recent studies have shown it to be both a useful T stimulator and estrogen blocker . The results of one clinical study showed that 6mg of boron daily for 2 months saw free testosterone rise 29.5%. Just 5mg here but it’s still one of the better choices.


Anything Missing?

Sytheroid has a lot of the test boosting basics missing. Zinc and magnesium would make great additions to the boron for example, and once the D-AA is topped up properly Vitamin D3 (and then K2) would be perfect partners.


Even though there are a couple of good picks here, on the whole the formula is almost as poorly judged as the name. Syntheroid would make a great cyborg from the future, but it doesn’t make a great natural test booster.

Even worse, at this price you can buy some of the best brands we’ve seen. Describing this product as ‘The World’s Most Powerful Testosterone Booster’ really is science fiction;