• Positive

    • No proprietary blends
    • Contains boron
    • May help energy levels
    • Reputable company
  • Negative

    • Only one direct T booster
    • Some ingredients under dosed
    • A few unproven choices
    • Expensive
  • Ingredients :
  • Price :
  • Trust :
  • Testimonials :
  • Company :
  • Overall Score: 5.6/10

Do you work hard at the gym but still find you struggle to gain muscle?  The problem could be because you’re body isn’t producing its peak level of testosterone.  That’s where N.O.x Test SX-7 Black Onyx, a natural T booster from Muscletech claims to help.

There’s no question a natural booster can be an effective way to safely raise your male hormone, the challenge is finding the really quality ones.

N.O.x Sx-7

N.O.x Test SX-7 Black Onyx sets out with 2 main goals: to increase your free T and to up nitric oxide levels in the body.  Free T is the stuff not tied up by the protein SHBG and so available to our body to use.  Strong nitric oxide levels on the other hand improves blood flow to fuel the muscles and keep you working out for longer.

That all sounds ideal, but how well can Muscletech’s formula get the job done?  Happily there’s not a proprietary blend in sight – we’ve got all names and doses on the label – so let’s find out.

How Does It Work?

At a Glance

  • L-Citrulline & L-Arginine to stimulate blood flow
  • Quercitin & Rhodiola to raise energy
  • DIM to control estrogen
  • Boron to boost T.
  • Bladderwrack extract to contol blood sugars.
  • Ginkgo Biloba to sharpen focus

We’llget to how well all this works right after we’ve dealt with the overall scores

The Scores

N.O.x Test SX-7 Black Onyx

N.O.x Test SX-7 Black Onyx is a weird one.  There are no truly bad choices here, but a lot of them would be better suited to a pre-workout supplement. A goal of this product is to raise exercise performance, but with only with only boron directly boosting T the recipe seems a little lopsided.  Although there is a good selection of energy booster here, like Rhodiola Extract and L-Citrulline, there’s a question over if the latter has an effective amounts.


The $40/£50 mark is getting up towards the higher end of the booster market and although Muscletech is a reputable company and there are some useful ingredients here, we feel like they’ve missed the mark with this one.  There’s better value for money out there.


Muscletech are a well-known company who are totally above board, so there’s no scams or dangers here.  The only things we’d take issue wish is N.O.x Test SX-7 Black Onyx presenting itself as a T booster, yet only really including boron to do that job.  Also a few ingredients may be below an active dose or need a little more research.


No testimonial section on the Muscletech website so its customer feedback on retail sites we’re going on.  This is generally positive, with several people noting an increase in energy.  However there are those who saw little benefit, and without the detail given in a dedicated testimonial section, it’s difficult to get an overall sense of quality before parting with cash.


Muscletech are a very successful supplement company worldwide reach. They have products of all kinds making up the Performance Series, Essential Series, 5X-7 Series and others. Their website is slick and they have plenty of athletes going to bat for them.

How Do I Take It?

Users should take 1 serving of 1 capsule 4 times daily.

N.O.x Test SX-7 Black Onyx’s name might be a mouthful, but this serving schedule isn’t.  In fact credit where it’s due this is dead on.

One cap 4 times a day is no hassle and it’s keeping the active ingredients topped up through the day.  That’s exactly what you want.

N.O.x Test SX-7 Black Onyx Side Effects?

Honestly we wouldn’t expect to see any adverse side effects based on this formula and none have been reported.

Where Can I Get It?

Customers can find this product in a range of places but the cheapest we came across was $49.94 at Amazon.com.  In the U.K you can find it at Prozis.com

Ingredients – In Detail


This amino acid can really help blood flow once it is in the body and converted to L-Arginine.  1.5g might seem a huge amount but most studies achieved results with somewhere between 6-8g, so how well this will work is debateable.



Yup that’s here too.  Like we say this is really what gets your blood moving, but it isn’t easily absorbed by the body and supplementing effective levels is difficult.  Why they didn’t just double down on the L-Citrulline, which ends up as this anyway, we’re not sure.



Championed these days for its antioxidant qualities, studies have been pretty disappointing.  One study shows it can increase energy output for a short time and may reduce inflammation and oxidative stress, allowing you to recover quicker.


Red Wine Extract

The key nutrient here is resveratrol.  It’s every wine fan’s get out of jail free card because it’s what could make the odd glass good for you.  Its strength is mainly as an antioxidant, but some in vitro studies show it can cut the conversion of T to estrogen in breast cancer cells.  Though until we see some human studies, we’re not getting excited.


Rhodiola Extract

This is not the worst choice in the world. It doesn’t help T but studies show it can reduce the heart’s response to exercise, making it feel easier for longer.  It does this in doses as low as 200mg, so 700mg plus here should be helpful


Broccolli Powder

DIM is a nutrient found in green leafy veg which some trials show can limit the creation of estrogen.  As we’ve covered the lower that is the higher T can get, so it potentially useful.  However in certain doses, other work suggests it can raise the female hormone.  It’s not so much an estrogen inhibitor as it is a modulator.  A tad risky.


Boron Citrate (5% Boron)

Amazingly for a T booster, this is the one ingredient with a proven track record of upping the hormone.  In fact it has been shown to also lower estrogen at the same time.  So more ingredients like this would’ve been nice.


Bladderwrack Extract

This nasty sounding plant actually has the ability to help control blood glucose levels and keep insulin balanced.  This is important because if insulin is unbalanced it can block T.  Although at just 50mg, we’re not sure how much help this will be.


Ginkgo Biloba

The best use of this is to boost cognition.  We’d say this helps keep you focused during a workout, but Ginkgo Biloba’s main strength is memory and halting the mental decline of age.  So this is wide of the mark in a couple of ways.


Anything Missing?

For a muscle building booster this is missing more than a few essentials.  Where’s the D-Aspartic Acid, or vitamin D? Minerals like zinc and magnesium would’ve strengthened the formula (and you) too.


This might be okay from a workout aid point of view, but the imbalance in the formula and high price mean compared to other better rounded T boosters it falls short.