VMI Sports K-XR: An Evidence-Based Review

K-XR is a pre-workout by VMI Sports, the brand behind our top rated PCT Supplement, A-XR PCT…

VMI Sports K-XR



VMI Sports claims K-XR will provide:

  • Intense Pumps
  • Energy
  • Focus/Cognitive Enhancement

These are the typical claims attached to just about every pre-workout, of course, but let’s take a look at the K-XR ingredient profile and see what it’s capable of…

K-XR Ingredients

VMI breaks the Supplement Facts panel of K-XR into three proprietary blends:

  1. Intense Pump Blend
  2. Maximum Energy Blend
  3. Focal and Cognitive Enhancing Blend

Unfortunately, this makes it difficult to determine the true efficacy of each ingredient but we can try to ballpark it…


Beta-Alanine is the rate limiting amino acid in Carnosine synthesis.  Carnosine, a dipeptide composed of Beta-Alanine and Histidine, is capable of reducing Lactic Acid build-up in muscle tissue so higher muscular Carnosine is associated with greater muscular endurance.

At this point, Beta-Alanine has been extensively researched (multiple studies) and it has proven quite reliable for enhancing muscular endurance via increasing muscular Carnosine levels.  It takes a week or two for the effects to become noticeable, but you’ll be able to go longer and harder during your workouts over time.

K-XR contains an undisclosed dose of Beta-Alanine, but we’d estimate it’s atleast 1.6g, technically a clinical dose if you take it on a daily basis.


Taurine is an amino acid with anti-oxidant properties which has been studied fairly extensively in the area of exercise performance enhancement.  Unfortunately, while it has been shown to slightly enhance exercise performance in one study, it has failed elsewhere, meaning it’s kind of unreliable for that.

However, Taurine has been shown to reduce oxidative damage in muscle tissue, effectively enhancing exercise recovery.  This gives it a perfectly legitimate use as a supplement, it’s just that many supplement companies have exaggerated the benefits.

VMI doesn’t list the exact dose of Taurine in K-XR but it’s probably somewhere around 1000mg.  Assuming that’s accurate, we’re looking at a clinically effective dose.


Theobromine is a natural component of Cocao.  It’s in the family of chemicals known as Xanthines, along with Caffeine.  While it is considered a cardiac stimulant (increased heart rate), it is not a psychoactive stimulant, meaning it won’t give you a rush of “energy” like Caffeine.

Still, it has implications for performance enhancement in that it may allow for optimal oxygen intake during exercise.  It hasn’t been studied, but the mechanism exists.  We have no idea how much Theobromine is present in K-XR.


Caffeine triggers the release of Catecholamines, a group of chemicals which includes Noradrenaline and Dopamine.  These chemicals are responsible for that feeling of enhanced focus and energy that you get from consuming Caffeine.

It has been shown in many studies to enhance exercise performance, both muscular endurance and strength (under certain circumstances).

It generaly forms the basis for stimulant-containing pre-workouts because it is safe and reliable (at an appropriate dose).

VMI lists three types of Caffeine on the label of K-XR:

  1. Caffeine Citrate
  2. Caffeine Anhydrous
  3. DiCaffeine Malate

Each type of Caffeine may have a distinct structure that makes it absorb quicker or slower, but for the most part, Caffeine is Caffeine.  VMI Sports doesn’t list the amount of Caffeine on the K-XR label, but our guess is somewhere around 300mg, give or take 50mg let’s say.

This is enough to make the average person noticeable more alert and focused, have better workouts, and increase fat-oxidation…and that’s not even the only stimulant!


Higenamine, also known as Norcoclaurine, is a stimulant with beta-adernergic agonist properties, meaning it can increase the amount of fat you burn during exercise.

It hasn’t been studied in humans, but beta-adrenergic agonists are beta-adrenergic agonists.  How it will effect you mentally is unknown, but it will definitely increase fat-burning capacity during your workouts.

This may naturally translate into more energy and the ability to go longer and harder.

As with the other ingredient in K-XR, there’s no indication how much Higenamine VMI Sports tossed in there.

Rauwolfia Vomitoria Extract

Rauwolfia Vomitoria is a plant species which contains Rauwolscine, a potent stimulant with alpha-adrenergic receptors antagonist properties.  In this respect, it functions as the inverse of Higenamine.

Alpha receptors tell your body to stop burning fat, so by blocking them Rauwolscine allows your body to burn more fat during your workouts than would otherwise normally be possible.  We discuss Rauwolscine in much more depth in our article Rauwolscine: The Most Powerful Fat-Burner That’s Still Legal as well as the efficacy of Yohimbine Vs. that of Rauwolscine in this article.

VMI Sports claims this particular extract is standardized for 90% Rauwolscine, but as we discuss in our article Why You Really Can’t Trust Most Supplement Companies, extracts are iffy.  Furthermore, there’s not indication of how much total Rauwolfia Vomitoria extract there is to begin with.

Choline Bitartrate

Choline is vitamin-like substance (not technically a vitamin, but close) which is required for the synthesis of Acetylcholine, the neurotransmitter in the brain most closely associated with various aspects of cognitive function and muscle contraction.

It hasn’t been studied in humans much in the area of performance enhancement, but it’s possible that Choline supplementation can enhance muscle contractions and cognitive function.

Unfortunately, Choline Bitartrate is not particularly bioavailable, so alot would be needed.  Probably more than whatever is present in K-XR.

Huperzine A

Huperzine A is a potent inhibitor of Acetycholinesterase, an enzyme which breaks down the Acetylcholine (remember, the neurotransmitter associated with cognitive function and the mind muscle connection).

It hasn’t been studied in the area of exercise performance enhancement, but the mechanism exists by which it may optimize the mind muscle connection as well as other aspects of cognitive function.

Huperzine A is so potent that it needs to be dosed in micrograms, so common doses range from 50-200mcg.  you don’t want to over-do it with this stuff, trust us…

K-XR Ingredient Takeaway

K-XR definitely has what it takes to provide energy, focus, and an overall enhancement of cognitive function.  In terms of stimulants, it’s heavy, but not overwhelming.  In terms of non-stimulant performance ingredients, it’s kind of light, but does contain enough Beta-Alanine to increase muscular endurance over time.

Is K-XR Safe?

If you’re not overly stimulant sensitive, you have nothing to worry about.  If you are pretty sensitive to stims, this formula probably isn’t for you…but if you must, start with a lowe dose.  Definitely don’t combine K-XR with other stimulant-containing products.

Where To Buy K-XR

K-XR is available through:

Wher you’ll also find the rest of VMI Sports’ products along with the opportunity to get free samples and discounts.

The Bottom Line

K-XR is worth considering for anyone who is primarily concerned with energy and focus.  It lacks some of the performance enhancing ingredients commonly found in other pre-workouts these days, but the “everything but the kitchen sink” approach is getting old anyway.  It’s nice to see a pre-workout that is moderately well-rounded but emphasizes a particular aspect (in this case focus/energy) to the extent that it’s actually better than competitors.

Too many pre-workouts these days are just the same blend of the same ingredients.  Clinically dosed or not…it gets old.  Thank you to VMI Sports for putting out something unique.

If you’re still not sure which pre-workout is right for you, check out our Best Pre-Workout Supplements list for some recommendations. exists to educate the supplement community and seperate the science from the hype.

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