USP Labs MaxREPS: An Evidence-Based Review

MaxREPS is a non-stimulant pre-workout formula by USP Labs which promises enhanced performance and pumps without the use of Caffeine…



L-Citrulline Malate 2:1

L-Citrulline Malate 2:1 is simply the amino acid L-Citrulline bonded with Malic Acid in a 2:1 ratio favoring L-Citrulline.  Citrulline is an amino acid involved in the several physiological functions including Nitric Oxide production (where it is converted to Arginine and then into Nitric Oxide) as well as a detoxification process known as the Urea Cycle, where toxic byproducts such as Ammonia are convered into Urea and excreted from the body.

Both of these roles provide mechanisms by which Citrulline may favorably enhance performance, and the research is overwhelmingly in favor of it.  Citrulline has not only been shown to increase Nitric Oxide levels more effectively than Arginine, but also to improve muscular endurance and reduce muscle soreness.

The clinical range is  anywhere from 6-9g, but USP Labs has elected to use the same precise 8g dose used in one of the more notable studies in which Citrulline was shown to increase the amount of bench press reps subjects were able to perform later in the workout.

Based on Citrulline alone, MaxREPS +NO3 has what it takes to enhance muscular endurance and provide some noticeable pumps.

Arginine Nitrate

Arginine Nitrate is the amino acid Arginine bonded with Nitric Acid (the Nitrate).  NO3-T is a patented process by which Nitrates are added to free amino acids (like Arginine).  We’ve seen quite a few different amino/nitrate combinations using NO3-T technology, but Arginine Nitrate seems to be a favorite.

Unfortunately, there is no research on NO3-T, just some patents which claim better absorption and some sort of synergistic benefit, but that doesn’t mean it actually works.  You can write whatever you want on a patent application and the USPTO can’t take the time to see if everyone is actually right about what their claiming.  It’s just a way of protecting intellectual property, even if that propery isn’t worth a whole lot.

We’re not saying Arginine Nitrate isn’t effective.  It very well might be.  USP Labs would probably say that Arginine Nitrate boosts Nitric Oxide production because it contains two distinct precursors to Nitric Oxide, Arginine and Nitrate.  However, this remains conjecture until we see some studies.

Again, not ruling it out as effective.  Just not taking the marketing claims surrounding Arginine Nitrate (and NO3-T in general) at face value.


USP Labs is probably one of the first companies we’ve seen using L-Citrulline when there’s already I highly effective clinical dose of Citrulline Malate in the formula.  Usually when we see both of these ingredients side by side it’s just a way of lowering costs since L-Citrulline is cheaper than Citrulline Malate, but we’re thrilled to see that isn’t the case with USP Labs!

L-Citrulline is capable of raising plasma Arginine levels and ultimately increasing Nitric Oxide levels.  Increased Nitric Oxide activity is generally seen as favorable for physical performance and may provide some noticeable pumps as well.

Vitamin C

Vitamin C plays a vital role in circulatory health, not to mention hundreds of additional physiological functions, so it is often incorporated into pump/performance pre-workout supplements.  Unfortunately, there isn’t any research which indicates that it can be particularly useful, nor is there any logic to suggest that it would be.

Most people are already getting tons of Vitamin C because it’s naturally occuring in just about all vegetables and fruits, not to mention added into a lot of fortified foods that you might eat.  Still, in the context of MaxREPS +NO3, it doesn’t do any harm either.

Is MaxREPS +NO3 Safe?

MaxREPS +NO3 is entirely safe for the average healthy individual but should probably not be combined with any blood pressure medication as there are some ingredients in the formula that have the capacity to lower blood pressure.  The formula contains no stimulants and is therefore stackable with any other pre-workout supplement, stimulant or not.

The Bottom Line

MaxREPS +NO3 is undoubtedly an effective pump/performance enhancing pre-workout.  The massive 8g dose of Citrulline Malate is also sure to boost your muscular endurance and reduce muscle soreness after exercise.  If you’re looking for a non-stimulant pump-enhancer that will make you perform better, give MaxREPS +NO3 a shot.

If you’re still looking for the right non-stimulant pre-workout supplement, check out our Best Non-Stimulant Pre-Workout Supplements List. exists to educate the supplement community and seperate the science from the hype.

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