Illustration, not a product photo.
A simple amino acid, usually taken as powder before bed.
281 owner comments (143 with a clear rating) from r/Supplements, r/sleep, r/insomnia, r/Nootropics, May 2026 to October 2026. Top 15% of the 20 rated supplements.
Value for money: Not rated. The example products differ too much in dose to compare cost fairly. How we score.
Glycine is rated about average among the supplements we track: 3.9/5. Of 143 rated owner comments, 113 were positive, 6 mixed and 24 negative; 15 mention an unwanted effect. People talk most about deeper sleep and taste & form.
Reddit comments are self-reported and unverified. They tell you what people noticed, not whether a supplement works or is safe for you.
Our guide covers the serotonin caution for 5-HTP and tryptophan. Reddit owners also rank supplements by getting to sleep reports. People also compare supplements for staying asleep on Reddit.
Supplements can interact with medicines. Talk to a doctor or pharmacist first, especially if you are pregnant, take prescription medicine (including sleep, anxiety or antidepressant medicines), or have ongoing sleep problems. See sleep supplement safety and interactions.
| Context | Rated owner comments | Positive | Negative | Unwanted effects |
|---|---|---|---|---|
| Deep sleep | 22 | 20 | 0 | 1 |
| Staying asleep | 14 | 9 | 4 | 4 |
| Falling asleep | 11 | 8 | 2 | 0 |
| Morning grogginess | 4 | 2 | 1 | 3 |
| Anxiety at night | 3 | 1 | 2 | 2 |
4/5 Deeper sleep“glycine on its own was the missing piece for me for years.”
5/5 Taste & form“Glycine is what I swear by. One teaspoon with green tea in the morning and one before sleep. I took it primarily for collagen but with time noticed the effect of calmness, it is now harder for me to become agitated and stressed.”
4/5 CostDeeper sleep“I have gone from waking every few hours to full nights of great sleep with this stack: 3g of glycine and 2 capsules of SleepElite about 30 minutes before sleep.”
2/5 Side effects“i experience a paradoxical effect to glycine, it gives me extreme anxiety & insomnia.”
2/5 Emotional bluntingMood“I'd like to add a caveat about glycine; it caused depression and anhedonia when I used it to support my sleep.”
5/5 Taste & form“I find glycine in larger doses really helpful for sleep and pain reduction.”
1/5 Side effects“It turned out to be bad for me - I guess many can't tolerate the glycine.”
4/5“I have been taking a blend of glycine, magnesium glycinate, apigenin and a few others and have seen big improvements in my whoop sleep score, so look into that if you are seeking better supplementation.”
4/5 Deeper sleep“I take glycine like 30 minutes before bed and it definitely helps with sleep quality.”
4/5“Glycine on its own is great too and it is a mast cell stabilisator.”
5/5“Magnesium glycinate and glycine for sleep were life changing for me.”
4/5 Side effectsDeeper sleep“I think certain people can't tolerate the Glycine.”
4/5 CalmingMorning grogginess“Its supposed to convert to L-glycine to some degree which is also supposed to promote sleep.”
4/5“The one I use for sleep issues is Mg Glycinate, from what I have learned is that is better difficult for substances to actually reach your brain, multiple sources though relate glycine, the amino acid, as one of the best absorbed by the…”
4/5 Takes time“I've been taking NAC+Glycine for about six months, scoop in the morning and a scoop at night and it takes a few months but I definitely feel better....like the OP said, it's not a high or rush, I just feel...better.”
4/5 Falling asleep faster“I take 3g before bed with mag glycinate, and that double-tap on my glycine receptors really helps me fall asleep”
4/5“Mag glycinate and glycine both wreck my sleep, but I have much better results with mag taurate.”
1/5 Side effects“Glycine makes me feel absolutely awful \~ waking for multiple hours in the middle of the night, followed by anxiety the following day.”
4/5“I do like glycine before bed the cooling helps me sleep”
4/5“Also I ended up fixing the creatine insomnia issue by taking high dose glycine, as recommend by Chris Masterjohn.”
3/5 Deeper sleep“Unfortunately creatine and glycine haven't moved my deep sleep at all.”
4/5 Deeper sleep“The difficulty is that the creatine dose and timing changed while glycine remained part of the routine, and “deep sleep doubled” is coming from a wearable estimate rather than a direct measurement of sleep architecture.”
4/5“I learned to take glycine for sleep. It helps the brain. I have crohns and it got my gut microbiom off bad!”
4/5 CostMorning grogginess“This is an incredibly solid list and I am so glad you put glycine at the very top.”
4/5 Taste & form“I've tried all these but the winning combo for me was magnesium glycinate (one pill 140mg) at night and glycine mixed into an herbal tea to sip until bed.”
2/5“I've been telling everyone who will listen about the joy glycine has brought to my life.”
5/5“Try Glycine, magnesium citrate or glycinate and Llysine before bed.”
4/5“I take 130mg magnesium glycinate and 2000mg glycine before bed.”
4/5 Taste & form“I take a sleep supp thats a premixed liquid iv style packet containing them and others like glycine and magnesium glycinate and its helped me a lot, and my whoop scores have improved a lot.”
4/5 Taste & form“The supplement that consistently helps me get 7-8 hrs on uninterrupted sleep is glycine.”
4/5“Try taking some NAC with the magnesium glycinate, you can even add some glycine on top that way.”
4/5 Deeper sleep“no, i take all my stimulants pretty early in the day, and i use magnesium and glycine for sleep, my sleep is pretty okay, i almost always remember my dreams and wake up refreshed”
4/5 Deeper sleep“Glutathione (injectable) or NAC+glycine (either oral or injectable) has been the best for me in regards to staying asleep and deep sleep.”
4/5“I actually take glycine with nac before bed.”
4/5“magnesium glycinate with glycine is nice combo for sleep - i do something similar and works great for me”
These are examples of Glycine products sold on Amazon. They are not ranked by Reddit and the score above is for the ingredient, not a specific product. Check the label for dose and other ingredients.
Published studies (we list them so you can read the evidence yourself; inclusion is not an endorsement):
Across 281 Reddit comments from people who say they have used it for sleep, 113 of 143 rated comments were positive and 24 negative, for a SnoozeVerdict score of 3.9/5. These are self-reported experiences, not clinical evidence.
15 of 143 rated owner comments (10%) describe an unwanted effect such as grogginess, headaches, vivid dreams or an upset stomach. Check the safety notes on this page and ask a doctor or pharmacist before starting.
Most rated owner comments come from people who talk about deep or restful sleep (22 comments, 20 positive).
No. The score summarizes Reddit owner comments only. Factual statements on this page link to NIH or PubMed sources, and nothing here is medical advice.
“I've been taking l-theanine for like 8 years now, no side effects, withdrawls when I stop, or anything negative from it at all.”
What owners report →
“I take tyrosine daily but I only take 5-htp once in a while on a weekend where I can sleep in a bit longer.”
What owners report →
“L-tryptophan which is what makes it the most effective for me, and I'm really hard to sedate!!”
What owners report →Comparisons: Magnesium glycinate vs Glycine · L-theanine vs Glycine · Melatonin vs Glycine · Taurine vs Glycine
Last updated 2026-11-04. Mentions scanned: 1009 in 611 threads.