Glycine, glutathione levels and potential health effects in people and animals
What it found
Extra glycine raised tissue glutathione in several animal studies.
In people on low-protein diets, signs of limited glutathione production were seen.
What they found
Studies in people
Low protein diets in people
People eating vegetarian or low-protein diets had higher levels of a waste product linked to low glutathione. This suggests dietary glycine can limit glutathione production in normally fed humans.
Animal and lab studies
Glutathione in animals
Several animal studies reported that giving extra glycine increased tissue glutathione levels.
Studies in people and animals
Possible health benefits
The authors say extra glycine may help blood vessel function, heart size, metabolic syndrome, diabetes complications, inflammation, liver protection, and sleep.
Other findings
Glutathione production limits
Tissue glycine levels are lower than what the enzyme needs to work at full speed. When glycine is too low, the body cannot keep up normal glutathione production.
Other roles of glycine
Glycine helps build several important molecules in the body. It also acts on certain cell receptors, slows sugar damage to proteins, and boosts liver output of a substance that clears hydrogen peroxide.
What the authors conclude
- They call for clinical research to test how extra glycine affects glutathione levels in people.
- They advise studying its impact on various health disorders as well.
How it was done
Glutathione is a key antioxidant that fights inflammation caused by hydrogen peroxide. The authors wanted to know if extra glycine could boost glutathione production like other supplements do.
The authors searched PubMed for relevant research on glycine and glutathione. They looked at studies in both people and animals. No specific number of studies or time frame was given.
What it can’t tell you
- We summarised it from the abstract only.
- This is a review of existing literature rather than a new trial.
- It cannot prove that taking extra glycine causes better health outcomes in people.
- Animal results showing higher glutathione may not match what happens in humans.
Who paid
- Authors work at
- Mid America Heart Institute, MO
The paper
- Title
- Dietary Glycine Is Rate-Limiting for Glutathione Synthesis and May Have Broad Potential for Health Protection
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Abstract only
- Cite
- McCarty MF, O'Keefe JH, DiNicolantonio JJ (2018). Dietary Glycine Is Rate-Limiting for Glutathione Synthesis and May Have Broad Potential for Health Protection. Ochsner journal. doi:10.1021/bi400451mFree full textPubMed 29559876DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error