Can Glycine Help You Wake Up More Refreshed? A Natural Amino Acid That Might Improve Sleep Quality
If you wake up feeling groggy, foggy, or just plain tired — even after a full night of sleep — you’re not alone. A surprising number of people report being unsatisfied with their sleep, despite getting enough hours.
But a recent study suggests that a simple amino acid called glycine may help.
What Is Glycine?
Glycine is a natural amino acid found in foods like meat, fish, dairy, and legumes. It also plays several roles in the body, including:
Supporting the nervous system
Acting as a calming neurotransmitter
Helping regulate core body temperature and circadian rhythm
And it turns out, glycine might also make you feel more alert and refreshed in the morning — even if your total sleep time doesn’t change.
What the Study Found
In a randomized, double-blind trial, 15 women who reported poor sleep were given either:
3 grams of glycine, or
A placebo
They took the dose about an hour before bed for 4 nights.
Each morning, they answered sleep quality surveys measuring:
Fatigue
Mental clarity
Mood
Overall sleep satisfaction
The results?
Feeling "very lively" improved significantly (P = 0.008)
Feeling "extremely peppy" improved (P = 0.031)
"Clear-headedness" upon waking also improved (P = 0.027)
A trend toward feeling more refreshed was noted, too (P = 0.065)
Interestingly, sleep duration and sleep onset time did not change — but people felt better in the morning.
Glycine didn’t knock people out — it helped them feel more rested and alert when they woke up.
(Inagawa et al., 2006)
What Makes Glycine Different from Sleeping Pills?
Unlike traditional sleep aids, glycine:
Does not cause drowsiness or next-day grogginess
Does not create dependency or rebound insomnia
Has a high safety profile, even in higher doses (up to 30g/day in other studies)
In short, glycine may be gentler and safer than over-the-counter sleep medications — making it a great option for people with occasional sleep complaints.
Who Might Benefit from Glycine?
Glycine might be helpful for people who:
Wake up tired despite a full night’s sleep
Struggle with morning brain fog
Want a natural sleep-support option
Don’t want to rely on melatonin or sedatives
It’s not a sedative — it’s a sleep-enhancing nutrient.
How to Take It
In the study, participants took 3 grams of glycine powder about an hour before bed. This is equivalent to roughly:
½ teaspoon of glycine powder
Available at most health food or supplement stores
Always talk to your doctor before starting a new supplement, especially if you’re pregnant or on medications.
TL;DR
Glycine is a natural amino acid that may improve how you feel in the morning
It doesn’t change sleep time — but it makes you feel more refreshed, peppy, and clear-headed
It’s safe, gentle, and worth trying if you struggle with sleep quality
Source:
Inagawa K, Hiraoka T, Kohda T, Yamadera W, Takahashi M. Subjective Effects of Glycine Ingestion Before Bedtime on Sleep Quality. Sleep and Biological Rhythms. 2006;4:75–77.
https://doi.org/10.1111/j.1479-8425.2006.00193.x