Thread by @Outdoctrination

Glycine markedly improves sleep quality and daytime energy, with less than a teaspoon.

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The first study investigating glycine and sleep came out in 2006.

Subjects taking 3g of glycine within an hour before bed reported:

➠ Substantially decreased fatigue the next day
➠ Improved subjective sleep quality

They also reported feeling:

➠ Very lively
➠ Extremely peppy
➠ Very refreshed
➠ More clear headed in the morning

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The next study was published the following year, from the same research group.

People taking 3g of glycine prior to bed had:

↑ Sleep satisfaction
↑ Sleep efficiency (ratio of sleep time to the whole time in bed)
↓ Difficulty falling asleep
↓ Time to fall asleep

compared to placebo.

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Glycine also changed the sleep architecture on EEG.

As you can see, glycine made sleep stages significantly more uniform, less switching in and out of different states.

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Glycine also decreased the latency into each stage.

In other words, people taking glycine got into each sleep stage in less time.

This is on top of them falling asleep quicker.

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The following day, glycine lessened how sleepy people felt.

This was less pronounced immediately upon waking, but very much so apparent throughout the morning.

Decreased grogginess.

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Glycine also improved objective cognitive function.

Beyond just saying they feel better, people on glycine showed an improvement in memory from an object recognition test.

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These findings have since been corroborated both in humans and in animals.

For example, a 2012 study once again showed that 3g of glycine at bed improved cognitive performance the following day, and resulted in less sleepiness.

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Why is glycine so good for sleep?

In the brain, a region called the hypothalamus contains a portion called the suprachiasmatic nucleus (SCN).

The SCN controls the circadian rhythm, taking in cues from light and regulating functions like sleep and wakefulness based off of it.

Glycine is an amino acid we get from the diet, but it's also a neurotransmitter.

Specifically, it acts as an activator of the NMDA glutamate receptors in the SCN.

By activating this pathway, glycine:

➠ Increases growth factors / neuroplasticity in the SCN
➠ Lowers core body temperature (important for sleep)
➠ Raises blood flow in the skin
➠ Increases vasopressin, which prevents you from waking up to pee

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