Core Nutritionals Core Zzz Review

Core Zzz is a sleep-aid by Core Nutritionals which is designed to promote deeper, more restful sleep as well as aid users in getting to sleep quicker…

Core Nutritionals Core Zzz



GABA is the chief inhibitory neurotransmitter in the brain.  It’s primary function is to reduce brain activity so over-stimulation does not occur.  GABA receptors are the targets of several anti-anxiety drugs in the benzodiazepine family and supplemental GABA has been studied as a potential treatment for anxiety, stress, and sleeplessness.

A common misconception about supplemental GABA is that it is ineffective because it has trouble crossing the blood-brain-barrier.  To be clear, this isn’t true.  While studies have noted that GABA does not easily cross the blood-brain-barrier, multiple studies have noted reduced anxiety as well as improvements in sleep quality with GABA supplementation, indicating that enough of it is able to cross into the brain to have an effect.

With 3g per serving, Core Zzz has plenty of GABA!


Glycine is an amino acid which is involved in many processes throughout the body, but has been studied fairly extensively as a sleep-aid.  At doses of 3g, Glycine has been shown to reduce the time it takes to fall asleep, as well as improve both subjective and objective measures of sleep quality.

We discuss Glycine in-depth in this article.  Core Zzz contains a clinical 3g dose, capable of exerting the above-mentioned benefits.

Mucuna Pruriens

Mucuna Pruriens are generally standardized for the compound L-Dopa, a direct precursor to Dopamine.  Given Dopamine’s role in sleep, Mucuna Pruriens is commonly included in sleep-aids.  While L-Dopa is capable of increasing Dopamine levels, it’s not clear whether healthy people will benefit much from this in terms of sleep.

In instances of Dopamine deficiency, L-Dopa may be pretty useful, but if you have no such deficiency you may not notice much in the way of improved sleep.


Valerian is an herb commonly included in anti-anxiety and sleep supplements, mostly because of an extensive history of use in traditional medicine.

Unfortunately, there is insufficient evidence to support the notion that Valerian enhances sleep quality in healthy individuals and it doesn’t appear to be very good at reducing the time it takes to fall asleep either. Some studies have noted benefit but others have failed, meaning Valerian is, at the very least, unreliable.

It’s more of a folk-medicine if anything, and while it doesn’t hurt the efficacy of the Core Zzz formula, it may not do much either.


Ornithine is one of the three amino acids involved in the Urea Cycle, the other being Citrulline and Arginine.  While Ornithine does have some performance enhancement implications related to this role, it has also been shown to increase Growth Hormone (GH) release with acute doses.  This is likely why Core Nutritionals included it in the Core Zzz blend.

To be fair, there really isn’t too much research on Ornithine’s ability to increase Growth Hormone levels in the long term, and normalization does appear to occur pretty quickly, so it’s not clear how effective it is in the long run.  That said, it certainly doesn’t hurt the efficacy of the formula in any way and might actaully do something!


Melatonin is without a doubt the single most common ingredient in sleep-aid supplements, perhaps because it has been researched quite extensively and is reliably effective.

Melatonin has been shown to shorten the time it takes to fall asleep as well as improve quality and duration of sleep.  We discuss it in this article, but in short, it’s a great first supplement to turn to if you’re having trouble sleeping, and is a welcome addition to any multi-ingredient sleep-aid such as Core Zzz.

The Bottom Line

Core Zzz certainly has what it takes to reduce the time it takes to fall asleep and improve quality and length of sleep.  It doesn’t contain any questionable/dangerous ingredients, just a few that are proven and dosed according to clinical standards. exists to educate the supplement community and seperate the science from the hype.

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