Amino acids & precursors
L-theanine
4.0 (330 owner comments)
Calming effectSide effects
“The I found a liquid L theanine and that made all the difference in the world.”
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Amino acids & precursors · powder or capsules
Glycine: What People With Stress, Anxiety or Low Mood Report on Reddit
Illustration, not a product photo.
A simple amino acid, usually taken as powder before bed.
3.0 CalmVerdict score
77 owner comments (42 with a clear rating) from r/Supplements, r/Nootropics, r/sleep, r/insomnia, r/Anxiety, May 2026 to October 2026. Top 92% of the 24 ranked supplements.
Owner sentiment3.2
Recommendations1.0
Tolerability4.0
ValueNot rated
Value: Not rated. The example products differ too much in dose to compare cost fairly. How we score.
The short version
Glycine is rated below most supplements we track: 3.0/5. Of 42 rated owner comments, 25 were positive, 4 mixed and 13 negative; 8 mention an unwanted effect. People talk most about calming effect and side effects.
Reddit comments are self-reported and unverified. They tell you what people noticed, not whether a supplement works or is safe for you.
Here is what owners report about theanine vs GABA. Reddit owners also rank supplements by anxiety reports. People also compare supplements for everyday stress on Reddit.
More on Glycine
What it is
- Glycine is an amino acid. Small studies in Japan gave about 3 g before bed and measured subjective sleep quality.[PubMed]
- A 2024 systematic review summarized human studies of glycine across body systems.[PubMed]
Reports by concern
| Context | Rated owner comments | Positive | Negative | Unwanted effects |
|---|---|---|---|---|
| Anxiety & worry | 19 | 5 | 6 | 3 |
| Low mood | 16 | 3 | 2 | 3 |
| Everyday stress | 11 | 4 | 1 | 1 |
| Rumination & intrusive thoughts | 7 | 1 | 2 | 0 |
| Panic attacks | 3 | 0 | 1 | 0 |
What Reddit owners say
Commonly praised
- Calming effect: 13 owner comments
- Sleep depth: 4 owner comments
- Taste & form: 3 owner comments
Common complaints
- Side effects: 8 owner comments
- Calming effect: 3 owner comments
- Feeling flat or numb: 2 owner comments
- Mood: 2 owner comments
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 Calming effectGrogginess“Its supposed to convert to L-glycine to some degree which is also supposed to promote sleep.”
4/5“It has already helped quite a bit, and its only the second day without glycine.”
2/5 Side effects“i experience a paradoxical effect to glycine, it gives me extreme anxiety & insomnia.”
2/5 Feeling flat or numbMood“I'd like to add a caveat about glycine; it caused depression and anhedonia when I used it to support my sleep.”
+30 more owner comments
3/5 MoodSide effects“I've also had some very weird reactions to iron bisglycinate that are pretty confounding considering the amount of glycine in that is \*extremely\* low compared to the amounts we get in food.”
1/5 Side effects“It turned out to be bad for me - I guess many can't tolerate the glycine.”
2/5 Feeling flat or numbMood“I experienced Anhedonia when i took Nac ethyl ester with glycine”
4/5“That glycine + NAC combo seems like a decent starting point, both are pretty gentle on the system and NAC helped me a ton with intrusive thought loops a while back”
4/5 Calming effectCost“Its not magnesium alone, glycine part does heavy lifting.”
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.”
2/5“I think glycine makes me wired or causes a cortisol spike for me.”
3/5“Glycine worked for me but after awhile I felt depresso so had to stop.”
4/5 Calming effect“I find myself using L-theanine more and more instead of glycine these days.”
4/5“A similar effect helped me as well, but after a few days, glycine makes me feel tense, anxious, and unwell.”
4/5“I also use taurine, glycine, nac for different purpose but i read taurine and nac helps some with anxiety and racing thoughts.”
4/5 MoodSleep depth“Alcar and b1 have the strongest effect on motivation and anything with glycine in it motivates me.”
4/5 Calming effectTaste & form“But when I was trying to help a patient with NAC tolerance, I found reason to recommend taking some glycine along with it.”
4/5 Calming effectTaste & form“The nights between the tablet I use magnesium carbonate powder / Calm/ with a tsp of glycine powder mixed into Melissa tea.”
4/5 Calming effect“Magnesium and glycine both made me feel 'light' and maybe more relaxed, but also more alert.”
4/5 Calming effectSleep depth“Came here because glycine has been a miracle for me.”
2/5“I recommend taking it I stopped taking mine for anxiety cause I started seeing everyone talk about glycine and my anxiety got a lot worse so now I've started taking it again and I feel a lot berter”
4/5 Sleep depth“glycine knocks anxiety down noticeably for me, sleep quality goes up too.”
4/5 Mood“I feel like the addition of glycine must help this somehow.”
4/5 Calming effectFast-acting“Turns out it was the glycine; it can have an effect immediately.”
4/5 Calming effect“Glycine sometimes calms me down though.”
3/5“I tried glycine by itself, as recommended by a naturopath, and I had one of the worst panic attacks I've ever had.”
4/5“I sleep well how ever .I wake up feeling heavy in the body and depressed.I am taking Magnesium Bisglycinate and 5mg of Glycine.”
4/5 Calming effectCost“For me it was glycine on its own. I didn't expect much, but taking it before bed noticeably improved how deep and calm my sleep felt within a week or so. It's cheap, simple, and way less talked about than it probably should be.”
4/5 Calming effect“But overall, for me anyway, it works better than glycine does to chill me out.”
4/5 Side effects“I take it with collagen peptides and glycine...”
4/5“L-theanine doesn't have much of an effect for me either, very subtle, helped removed some of my jitteriness, but magnesium glycine helped a lot for stress.”
2/5 Calming effect“I would take glycine and then feel wired yet calm and would be kind of in a trance.”
2/5“Glycine used to also make me feel wired and anxious but I started taking SAMe for undermethylation problems.”
4/5 Calming effect“Also many people find glycine to be calming but a few people report it amps them up, maybe when taking too much in the beginning.”
Example products
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.
Example product · not Reddit-scored
Now Supplements, Glycine Powder, Cognitive Support*
$14.99 on Amazon (price as of 2026-11-03). Prices change; check Amazon for the current price.
Example product · not Reddit-scored
BulkSupplements.com Glycine Powder, 500g (Pack of 1)
$22.97 on Amazon (price as of 2026-11-03). Prices change; check Amazon for the current price.
Research to read
Published studies (we list them so you can read the evidence yourself; inclusion is not an endorsement):
- J Pharmacol Sci 2012: New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep.
- Geroscience 2024: The effect of glycine administration on the characteristics of physiological systems in human adults: A systematic review.
FAQ
What do people say about Glycine for stress, anxiety or mood on Reddit?
Across 77 Reddit comments from people who say they have used it, 25 of 42 rated comments were positive and 13 negative, for a CalmVerdict score of 3.0/5. These are self-reported experiences, not clinical evidence.
Do people report side effects with Glycine?
8 of 42 rated owner comments (19%) describe an unwanted effect such as drowsiness, headache, stomach upset or feeling flat. Check the safety notes on this page and ask a doctor or pharmacist before starting.
Who talks about Glycine most?
Most rated owner comments come from people who describe anxiety or constant worry (19 comments, 5 positive).
Is Glycine scored on clinical evidence?
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.
Related supplements
Amino acids & precursors
Taurine
3.7 (45 owner comments)
Calming effectTaste & form
“It does for me, I get jaw tension from strattera and adding taurine with my dose has made a difference”
What owners report →
Amino acids & precursors
L-tryptophan
3.5 (6 owner comments)
MoodFeeling flat or numb
“Ive been taking l-theanine and l-tryptophan and its made a huge impact on my mental health.”
What owners report →Comparisons: Glycine vs L-theanine · Glycine vs Magnesium glycinate
Last updated 2026-11-04. Mentions scanned: 351 in 253 threads.