PhosphaGrow SX-7 Black Onyx Review

PhosphaGrow SX-7 Black Onyx is the most recent edition to the Black Onyx Series by MuscleTech which, until now, consisted only of Hydroxycut SX-7 Black Onyx. As the name implies, the primary active ingredient is Phosphatidic Acid, an ingredient that MuscleTech seems quite interested in given that it also appears in Fuel:One Phospha Build as well as PhosphaMuscle

PhosphaGrow SX-7 Black Onyx



Phosphatidic Acid is a phospholipid component of cell-membranes which has been shown, in vitro, to stimulate mTOR, a signaling molecule which initiates muscle protein synthesis.

Fuel:One references one particular study from the “Nutrition & Metabolism” which found that Phosphatidic Acid enhanced mTOR signaling (measured in vitro) and ultimately increased muscle hypertrophy and strength in resistance trained males over an 8 week period.

Interestingly, this study compared the mTOR stimulating abilities of various Phosphatic Acid precursors from different sources and found that Soy-derived Phosphatic Acid was significantly more effective than egg-derived Phosphatidic Acid.

An earlier (2012) pilot study, published in the “Journal of the International Society of Sports Nutrition”, found that Phosphatidic Acid supplementation (750mg daily) increased squat strength and Lean Body Mass (LBM) slightly more than the placebo group in response to 8 weeks of resistance training.

Although the results of this pilot study were not as encouraging as the most recent (2014) study, they both indicate that Phosphatic Acid can enhance strength and muscle growth, at least to some degree.

PhosphaGrow SX-7 Black Onyx contains 750mg of Phosphatidic Acid per serving, a true clinical dose.


Astragalus has appeared across virtually every category in the bodybuilding supplement industry, but its inclusion in the PhosphaGrow SX-7 Black Onyx formula likely has to do with preliminary evidence that suggests it may help keep Estrogen levels in check.

Astragalus may help preserve male fertility, as evidenced in a 2012 study from “Phytotherapy Research”, but this does not appear to be due to any direct Androgen-signaling property, as Astragalus has failed to influence Androgen-receptor signaling in vitro.

Other than the above-mentioned implications, we’re not sure why MuscleTech chose to include Astragalus in the PhosphaGrow SX-7 Black Onyx formula.


Eurycoma Longifolia, also known as Long Jack, is generally included in testosterone-boosting supplements because of preliminary evidence that suggests it can encourage healthy Test levels.

A 2010 study published in the “Asian Journal of Andrology” found that supplementation with 200mg of an extract of Eurycoma Longifolia significantly improved various indications of male fertility (in humans), though the mechanism of action was unknown.

A 2012 study published in “Andrologia: Volume 44” (the same researchers from the above mentioned human study) found that men suffering from Hypogonadism (diminishing functionality of the gonads) who were treated with a 200 mg daily dose of Eurycoma longifolia extract reached normal Testosterone levels after a 30 day period.

Unfortunately, the amount of Eurycoma Longifolia present in PhosphaGrow SX-7 Black Onyx is appears pretty negligible judging by the overall weight of the proprietary blend and its position in the formula.


PhosphaGrow SX-7 Black Onyx is essentially a Phosphatidic Acid supplement fortified with some alleged test-boosting ingredients that may be under-dosed. While it does have some libido-enhancing potential, this effect would be fairly mild and doesn’t give PhosphaGrow SX-7 Black Onyx any clear advantage over other Phosphatidic Acid supplements.

If you’re looking for something that will actually help you gain lean muscle, check out our Best Muscle Builders List!

[expand title=”REFERENCES” tag=”h5″]

  1. Joy, Jordan M., et al. “Phosphatidic acid enhances mTOR signaling and resistance exercise induced hypertrophy.” Nutrition & metabolism 11.1 (2014): 29.
  2. Hoffman, Jay R., et al. “Efficacy of phosphatidic acid ingestion on lean body mass, muscle thickness and strength gains in resistance-trained men.” J Int Soc Sports Nutr 9 (2012): 47-53.
  3. Winter, Jeremiah N., et al. “Phosphatidic acid mediates activation of mTORC1 through the ERK signaling pathway.” American Journal of Physiology-Cell Physiology 299.2 (2010): C335-C344.
  4. Tambi, M. I. B. M., M. K. Imran, and R. R. Henkel. “Standardised water‐soluble extract of Eurycoma longifolia, Tongkat ali, as testosterone booster for managing men with late‐onset hypogonadism?.” Andrologia 44.s1 (2012): 226-230.
  5. Zanoli, P., et al. “Influence of< i> Eurycoma longifolia on the copulatory activity of sexually sluggish and impotent male rats.” Journal of ethnopharmacology 126.2 (2009): 308-313
  6. Ang, H. H., S. Ikeda, and E. K. Gan. “Evaluation of the potency activity of aphrodisiac in Eurycoma longifolia Jack.” Phytotherapy Research 15.5 (2001): 435-436.
  7. Bhat, Rajeev, and A. A. Karim. “Tongkat Ali (< i> Eurycoma longifolia Jack): A review on its ethnobotany and pharmacological importance.”Fitoterapia 81.7 (2010): 669-679.
  8. Tambi, Mohd Ismail Bin Mohd, and M. Kamarul Imran. “Eurycoma longifolia Jack in managing idiopathic male infertility.” Asian journal of andrology 12.3 (2010): 376-380.
  9. Kim, Wonnam, et al. “Astragalus membranaceus ameliorates reproductive toxicity induced by cyclophosphamide in male mice.” Phytotherapy Research26.9 (2012): 1418-1421
  10. Kim, In Gyu, et al. “Screening of estrogenic and antiestrogenic activities from medicinal plants.” Environmental toxicology and pharmacology 25.1 (2008): 75-82.

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