PlainPill
SupplementSleep

L-Glycine

People mainly take L-Glycine for sleep. Based on 10 first-hand reports and 2 meta-analyses & systematic reviews in the medical literature. Ranked #1282 of 2,750 overall.

Compare with…Alternatives for sleep
19
User score
Mostly negative
20% positive0% mixed20% negative60% unclear

Of reports that state an outcome, 50% are positive.

Clinical research
BModerate research base
2
meta-analyses
2
RCTs
370
papers

What L-Glycine does, according to users

Of the people who reported each effect, the share who said it got better.

Sleep50% of 6
1 more with fewer than 3 reports
Anxiety0% of 1
betterno changeworse

What the research says

Systematic reviews and meta-analyses from PubMed, with their published conclusions.

BModerate research base

At least one meta-analysis, or 5+ randomized controlled trials. The grade measures how much human research exists — read the conclusions below for what it found.

Nutrients · 2022 · Meta-analysis / systematic review
Role of Phytoestrogen-Rich Bioactive Substances (Linum usitatissimum L., Glycine max L., Trifolium pratense L.) in Cardiovascular Disease Prevention in Postmenopausal Women: A Systematic Review and Meta-Analysis

Conclusion: Changes in the lipid profile showed a significant reduction in TC levels after the use of red clover (WMD = -0.11; 95% CI: -0.18--0.04; p = 0.0017) and a significant increase in HDL-C levels (WMD = 0.04; 95% CI: 0.01 to 0.07; p = 0.0165). This meta-analysis provides evidence that consuming flaxseed, soy and red clover can have a beneficial effect on lipids in postmenopausal women and suggest a favorable effect in preventing cardiovascular diseases.

PubMed 35745197 ↗
Eur J Obstet Gynecol Reprod Biol · 2021 · Meta-analysis / systematic review
Impact of phytoestrogens on treatment of urogenital menopause symptoms: A systematic review of randomized clinical trials

Conclusion: After using a variety of phytoestrogens in different forms indicators of urogenital atrophy and urinary disorders improved and women's sexual function improved after treatment. The use of phytoestrogens as a safe, low-risk compared to hormone therapy and almost accessible method for women can relieve urogenital symptoms and promote the sexual satisfaction and quality of life.

PubMed 33962824 ↗

Dosage people report

As stated by users — not a recommendation. Follow the label or your doctor.

2-5 gas reported
20 gas reported
before sleepas reported
1600 mgdaily
before bedas reported
45 minutes before bedas reported

Reported side effects

How often each side effect came up across all reports.

insomnia ×1anxiety ×1

What users say

Verbatim quotes, shortened only — each links to the original discussion.

“there are also numerous other benefits of l-glycine supplementation - sleep quality is the primary one.”
Source discussion ↗
“I like to alternate with l-glycine and d-ribose, plus creatine, taurine and dmae”
Source discussion ↗
“Glycine also fucks up a significant minority of people. Every week there's someone on here going on about insomnia and anxiety from mag glycinate.”
Source discussion ↗
“Get a melatonin supplement, l-glycine.”
Source discussion ↗
“It didn't do much for sleep or for obsessive thinking, so I don't think it's really worth it. (review from taking 20 grams)”
Source discussion ↗
Top discussions (5)

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User data from public discussions; research from PubMed. Information only, not medical advice — talk to a doctor before starting, stopping or combining anything. Data updated October 3, 2026. How we rate