Sleep Supplement Review: PreSleep

Almost two months ago I was saying PreSleep was my favorite sleep supplement… and that stands to this day.

PreSleep combines three of my favorite sleep supplements into one convenient powder:

  • Magnesium Glycinate
  • L-Theanine
  • Glycine

These three are highly synergistic and can be taken together almost every night.

How do they work?

Magnesium Glycinate

Magnesium is an ion that most of the population is deficient in. It exerts a powerful positive effect on sleep and the reduction of anxiety through its action on the NMDA glutamate receptor and contributes to an increase in GABA activity.

Magnesium actively reduces glutamate activity (especially in those that are deficient), along with a myriad of other functions it has in the body including energy production and use. For these reasons, magnesium is one of the only supplements I take daily and is a fantastic sleep supplement.

The glycinate form has the added benefit of providing extra glycine.


Theanine is a simple amino acid that is structurally very similar to glutamate. As such, most of its pro-sleep and anti-anxiety effects come from acting as glutamate.

However, instead of increasing glutamate activity, theanine decreases it directly and indirectly via AMPA antagonism and glutamine reuptake inhibition. This action inhibits excitatory receptors directly, while also reducing glutamate production via inhibition of glutamine reuptake.


Glycine is also an amino acid, but it functions directly as an inhibitory neurotransmitter in the brainstem and spinal cord.

As such, it has a direct positive influence on sleep. Glycine has been shown to induce better and quicker sleep, in part by reducing body temperature.

Generally speaking, when supplementing for sleep you want to decrease excitatory activity and increase inhibitory activity in the brain. Combined together these ingredients do exactly that, working extremely well to not only help fall asleep, but stay asleep.

Magnesium Glycinate and Theanine are already my favorite sleep stack of all time, so add a hefty dose of glycine to the mix and you’re left with a potent sleep cocktail.

My Personal Experience

PreSleep has quickly become one of my favorite supplements, period. 

Over the course of my experimentation with it, I have collected various bits of sleep data via my Whoop to see if PreSleep had any noticeable effects on my sleep.

There were no significant changes in any metric except for hours of sleep. It seems that on nights I took two scoops of PreSleep I slept for about 10 more minutes a night. Since I wake up at the same time every morning, I interpret this as I fall asleep quicker when I take PreSleep.

Subjectively, I would say I noticed the same thing. I found myself drifting off to sleep earlier and quicker than I do on average. I normally sleep exceptionally well, which is likely why I noticed no change in other sleep metrics as a result of PreSleep. However, when I do take it, I almost certainly fall asleep faster and spend less time lying in bed awake overall.

I would also like to note that I have not had a Whoop sleep score less than 100% when taking PreSleep, although I don’t have many nights with less than a 100%.

This is a highly effective combination of supplements for sleep, in my previous experience as well as with PreSleep.

Form Factor & Taste

To get my average dosing of PreSleep elsewhere, it would take me 10 pills and a scoop of powder. Now it takes me 2 scoops of a blue raspberry flavored powder. While you can get these all in powder form, magnesium glycinate powder is infamous for tasting horrid, which makes it impressive that PreSleep actually tastes good.

The blue raspberry taste is strong, which I personally enjoy and beats out flavorless bulk powders. Even if I didn’t, I think it’s still better than the alternative of choking down a ton of pills or measuring out various powders individually.

My Protocol Moving Forward

Being that I enjoy this supplement a lot and it is a combination of those that I would combine previously, I plan to continue using PreSleep moving forward. It is effective, tastes good, and can be used frequently with little to no risk of dependence due to the simplicity of its ingredients.

Here are my specific use cases moving forward:

-before bed on random occasion (2 scoops)

-before bed when I need a bit of help falling asleep or am a bit anxious (2 scoops)

Dosage per scoop:

-400mg Magnesium Glycinate

-400mg L-Theanine

-3g Glycine

1 scoop is enough for me to ‘feel it’, but I prefer 2 scoops since I find theanine most effective before sleep at dosages above 800mg. This may differ from person to person, but this is based on my previous experiments.

I also won’t be taking this every night, I’ve been taking PreSleep 3-4 times per week since receiving it. It’s my choice to not take any sleep supplement every single night so I don’t become mentally dependent on it. Not physically dependent, but that “I can’t sleep well unless I take my supplements” dependence. 


PreSleep is a fantastic supplement, combining three of my all time favorite sleep supplements into one convenient tasty powder form.

That being said, I don’t and won’t take this supplement every night. My light viewing behavior and lifestyle are what dictate most of my sleep habits. However, sleep supplements are great and can be extremely useful tools. 

PreSleep is and will continue to be my go-to sleep supplement for when I want/need anything more than simply just magnesium.

You can get it here (use code “BOWTIED10” for 10% off)

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