USP Labs Yok3d Review

USP Labs has recently reformulated Yok3d, probably in an attempt to stay current in a category (pump-based PWOs) that has seen a huge surge in the past year or two…

USP Labs Yok3d



Citrulline is a precursor to the amino acid Arginine, which is a precursor to Nitric Oxide (NO). As demonstrated in a 2007 study, supplemental Citrulline is significantly more effective at raising plasma Arginine than supplemental Arginine itself.

The problem with supplemental Arginine is that it is metabolized in the intestines and liver into other substances such as Ornithine and Urea. The intestines and liver contain relatively high levels of Arginase, the enzyme that converts Arginine to Ornithine and Urea. As a result, very little goes on to be involved with the synthesis of NO because it is being diverted for other purposes. Citrulline, on the other hand, is able to bypass the liver and is metabolized into Arginine elsewhere, where not as much Arginase is present. Thus, more of the Arginine is able to convert into NO.

A 2002 study, published in the “British Journal of Sports Medicine” found that Citrulline Mallate supplementation (6g/day for 15 days) significantly increased ATP production during exercise in healthy adult males. A 2009 study, published in the “Journal of Free Radical Research”, found that 6 grams of Citrulline Malate given to male cyclists before a race increased “plasma Arginine availability for NO synthesis and PMNs priming for oxidative burst without oxidative damage”. A 2011 study, the subjects of which were rats, found that supplemental Citrulline increased muscular contraction efficiency (less ATP was required for the same amount of power), in-line with the findings of the above-mentioned human study.

Overall, Citrulline has a few different mechanisms by which it may enhance exercise performance. That being said, the dose present in the reformulated Yok3d is like less than half the 6 gram dose shown to convey performance benefits.


Vitus Vinifera (or Grapeseed Extract) contains polyphenols (antioxidants). This ingredient seems to end up in more and more workout-related supplements, but most companies come up short when it comes to explaining why. Grapeseed extract has been shown to have a variety of benefits ranging from skin health to improving blood circulation. We suspect the latter is the reason for USP including it in a vasodilation formula. Indeed, antioxidants are important for anyone engaged in consistent exercise. However, this ingredient is by no means a miracle additive, and as far as its ability to cause “pumps”, the evidence is severely lacking.


Most of the research regarding Pinaster (Pine) Bark Extract’s effect on blood flow has been directed at certain conditions such as hyper-tension and Coronary Artery Disease (CAD). However, a 2007 study found that 180mg daily for 2 weeks effectively increased acetylcholine-induced vaso-relaxation in healthy men, indicating that Pine Bark (as Pycnogenol) can increase blood flow regardless of health state. This is good news for bodybuilders and athletes, and while the performance enhancement capabilities of Pine Bark remain under-researched, it may certainly be effective as a “pump” ingredient. Pine Bark can positively influence blood flow with relatively low doses, so it is certainly possibly (given a 3000mg) proprietary blend that Yok3d contains an effective dose.


The newly reformulated Yok3d is certainly a massive improvement over the previous formula. If you read our original review you’re aware of our disappointment with the original formula, and while this new formula isn’t particularly groundbreaking, it does contain some effective ingredients. Ideally we’d like to see more Citrulline (6g would be nice) but Pinus Pinaster definitely helps compensate and lends some efficacy to the formula as a whole. Ultimately, we feel there are still better pump-based/N.O. products out there, but the new Yok3d is definitely a step in the right direction.

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  3. Bendahan, D., et al. “Citrulline/malate promotes aerobic energy production in human exercising muscle.” British journal of sports medicine 36.4 (2002): 282-289.
  4. Sureda, Antoni, et al. “Effects of L-citrulline oral supplementation on polymorphonuclear neutrophils oxidative burst and nitric oxide production after exercise.” Free radical research 43.9 (2009): 828-835.
  5. Giannesini, Benoît, et al. “Citrulline malate supplementation increases muscle efficiency in rat skeletal muscle.” European journal of pharmacology 667.1 (2011): 100-104.
  6. Sureda, Antoni, et al. “Effects of L-citrulline oral supplementation on polymorphonuclear neutrophils oxidative burst and nitric oxide production after exercise.” Free radical research 43.9 (2009): 828-835.
  7. Belviranlı, Muaz, et al. “Effects of grape seed polyphenols on oxidative damage in liver tissue of acutely and chronically exercised rats.” Phytotherapy Research27.5 (2013): 672-677
  8. Belviranlı, Muaz, et al. “Effects of grape seed extract supplementation on exercise-induced oxidative stress in rats.” British Journal of Nutrition 108.02 (2012): 249-256.
  9. Enseleit, Frank, et al. “Effects of Pycnogenol on endothelial function in patients with stable coronary artery disease: a double-blind, randomized, placebo-controlled, cross-over study.” European heart journal 33.13 (2012): 1589-1597.
  10. Liu, Ximing, et al. “Pycnogenol®, French maritime pine bark extract, improves endothelial function of hypertensive patients.” Life sciences 74.7 (2004): 855-862.

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