RSP Nutrition Z-Elite Review

Z-Elite is RSP Nutrition’s sleep-aid which consists of ZMA and Melatonin…

RSP Nutrition Z-Elite


ZMA and Testosterone

A 2000 study from the “Journal of Exercise Physiology” found that 8 weeks of ZMA supplementation in college athletes undergoing a rigorous training programsignificantly increased Testosterone compared to subjects taking a placebo.

This study is often the only study that is cited as “proof” that ZMA increases Testosterone. The only issue is that there is one MASSIVE conflict of interest here. That is, this particular study was funded by Snac Systems, the company which originally developed ZMA. Furthermore, one of the study’s authors,Victor Conte, has a considerable equity stake in Snac Systems.  So we’ll let you guys draw your own conclusions about what that might mean.

If more studies corroborated the findings of this study, the conflict of interest could be over-looked. However, ZMA has failed to influence Testosterone in two later studies.
A 2004 study, published in the “Journal of the International Society of Sports Nutrition”, found no influence on Testosterone levels in individuals consuming ZMA for 8 weeks.
similar failure occurred in a 2007 study, published in the “European Journal of Clinical Nutrition”.

Zinc and Testosterone

A 2007 study from “Neuro Endocrinology” found that exercise significantly depleted Testosterone levels in male subjects and that Zinc supplementation was able to prevent this decrease.
These results indicate that Zinc supplementation is an effective means of encouraging optimal Testosterone levels which might otherwise become depleted by rigorous exercise.

Z-Elite contains 35mg of Zinc per serving, way more than enough to ensure the maximum benefits are achieved with regards to influencing healthy Testosterone levels.

Magnesium and Testosterone

A 1992 study, published in the “Journal of the American College of Nutrition” found that Magnesium (as Magnesium Oxide) supplementation resulted in a minor, though statistically insignificant, increase in Testosterone in healthy subjects.

A more recent (2011) study from “Biological Trace Element Research” yielded similar results, and noted that Magnesium increased Testosterone more in exercise subjects than in sedentary ones.

Overall, the research indicates that, while Magnesium may play a role in normalizing and possibly increasing Testosterone, any increases are likely to be small and have much to do with initial Magnesium status (deficient or not).

Given that Magnesium is a relatively common deficiency, athletes supplementing with Magnesium is certainly not a bad idea.

Magnesium and Sleep

The relationship between Magnesium and sleep has been studied fairly extensively, and there appears to be a two-way correlation, with Magnesium helping to correct sleep-related issues in some studies, and inadequate sleep reducing Magnesium levels as well.

A 2002 study, published in “Pharmacopsychiatry”, found that Magnesium was able to increase slow-wave (deep) sleep and reduce Cortisol levels, thus normalizing age-related changes in sleeping patterns in elderly subjects. These results were replicated in a 2002 study from “Public Health Nutrition” in older (59 give or take 8 year old) subjects with inadequate dietary Magnesium intake.

Overall, while Magnesium may not be particularly effective as a sleep-aid in individuals with high (more than adequate) dietary intake, it can certainly improve sleep quality in those whose diets are lacking.

Z-Elite contains 425mg of Magnesium per serving, more than enough to ensure adequate Magnesium levels.


Melatonin is a hormone secreted by the pineal gland, found in the brain. It is heavily involved in the sleep-wake cycle (by causing drowsiness when secreted) and has implications for increasing/regulating Growth Hormone (GH) levels. Due to its role in promoting sleep, supplemental melatonin has been used to correct and treat mild sleep disorders, as well as by people who experience mild sleeplessness. All evidence suggests that melatonin works very well when it comes to promoting sleep.

A 2004 study, published in the Journal of Clinical Endocrinology & Metabolism, found that Melatonin significantly increased REM sleep in subjects who suffer from lower than normal REM sleep durations.

Several other studies have demonstrated the ability of Melatonin to increase REM sleep duration, as well as decrease sleep latency (time to fall asleep).

Overall, Melatonin may be very useful as a sleep aid for individuals that have trouble obtaining full, restful sleep.  Z-Elite contains 3mg of Melatonin per serving which is in the middle of the clinical range and is considered an effective dose.

The Bottom Line

Z-Elite may certainly enhance sleep quality (due to Melatonin and perhaps Magnesium) and can potentially help preserve Testosterone levels.  So, RSP’s claims that Z-Elite “supports” healthy Test levels are accurate, but we just want to be clear here that this formula will not “boost” Testosterone beyond the normal range.

  1. Brilla, L. R., and Victor Conte. “Effects of a novel zinc-magnesium formulation on hormones and strength.” J Exerc Physiol Online 3.4 (2000): 26-36.
  2. Wilborn, Colin D., et al. “Effects of zinc magnesium aspartate (ZMA) supplementation on training adaptations and markers of anabolism and catabolism.” J Int Soc Sports Nutr 1.2 (2004): 12-20.
  3. Koehler, K., et al. “Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement.”European journal of clinical nutrition 63.1 (2007): 65-70.
  4. Kilic, Mehmet. “Effect of fatiguing bicycle exercise on thyroid hormone and testosterone levels in sedentary males supplemented with oral zinc.” Neuro endocrinology letters 28.5 (2007): 681-685.
  5. Cinar, Vedat, et al. “Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion.”Biological trace element research 140.1 (2011): 18-23.
  6. Brilla, Lorraine R., and Timothy F. Haley. “Effect of magnesium supplementation on strength training in humans.” Journal of the American College of Nutrition 11.3 (1992): 326-329.
  7. Kunz, Dieter, et al. “Melatonin in patients with reduced REM sleep duration: two randomized controlled trials.” Journal of Clinical Endocrinology & Metabolism 89.1 (2004): 128-134.
  8. Brzezinski, Amnon, et al. “Effects of exogenous melatonin on sleep: a meta-analysis.” Sleep medicine reviews 9.1 (2005): 41-50.
  9. Cajochen, Christian, et al. “Melatonin and S-20098 increase REM sleep and wake-up propensity without modifying NREM sleep homeostasis.” American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 272.4 (1997): R1189-R1196.

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