GlyNAC is simply a term used to describe co-administered glycine and n-acetylcysteine (NAC). Like NAC, GlyNAC is thought to reduce oxidative stress by increasing levels of glutathione (the most abundant intracellular antioxidant).[1]
What is GlyNAC?
GlyNAC is simply a term used to describe co-administered glycine and n-acetylcysteine (NAC). Like NAC, GlyNAC is thought to reduce oxidative stress by increasing levels of glutathione (the most abundant intracellular antioxidant).[1]
What are GlyNAC’s main benefits?
Preliminary research suggests that GlyNAC may reduce oxidative stress and improve metabolic health in conditions characterized by high levels of oxidative stress, such as type 2 diabetes (T2D), human immunodeficiency virus (HIV), and aging.[2][3] As is the case with n-acetylcysteine, these benefits are largely brought about by increasing intracellular levels of the antioxidant glutathione.[4]
Before discussing specific outcomes, it’s worth underscoring that, as of 2024, most studies on GlyNAC follow the same general methodology. People in the treatment group, who all have some condition of interest (e.g., people with HIV, people with T2D, or older people), receive some quantity of GlyNAC daily; their biomarkers of oxidative stress and metabolic health are measured at baseline, after the treatment period, and several weeks after the treatment has ceased. These biomarkers are compared to those of a group without the condition of interest (e.g., people without HIV, people without T2D, or young people) who have not received the treatment. Generally speaking, GlyNAC is able to shift the biomarkers of the treatment group to more closely resemble (and sometimes equal) those of the non-treatment group, and these biomarkers then return to baseline (i.e., worsen) after treatment is discontinued. This study design is certainly useful, especially with small groups, but the literature would still benefit from more randomized controlled trials.
With respect to specific outcomes, GlyNAC seems able to improve (i.e., reduce) fasting respiratory quotient, glucose oxidation, insulin resistance, and plasma free fatty acids in people with T2D.[5][1]
In people with HIV, GlyNAC has been reported to improve fasting glucose levels, measures of oxidative stress like thiobarbituric acid reactive substances (TBARS) and F2-isoprostane, and scores on the physical and mental components of the SF-36, which evaluates quality of life.[6][3]
One randomized trial in healthy older adults found that GlyNAC didn’t always raise blood levels of glutathione sulfhydryl (GSH), the reduced form of glutathione, and that GlyNAC’s ability to do so may be dependent on a person’s baseline GSH status (i.e., people with low GSH may benefit from GlyNAC, while people with normal levels of GSH may not).[7]
What are GlyNAC’s main drawbacks?
No notable side effects have been reported in the GlyNAC literature, although there have been some documented instances of NAC causing nausea, vomiting, and diarrhea.[8][9]
When NAC or GlyNAC are taken intravenously, NAC overdose is possible, and can result in red blood cell breakdown (hemolysis), low blood platelet count (thrombocytopenia), kidney failure, and possibly death.[10]
How does GlyNAC work?
GlycNAC is thought to provide its benefits largely by increasing the production of GSH. GlyNAC is simply glycine and cysteine (in the form of n-acetylcysteine), which are two of the three substrates necessary for the synthesis of GSH (via two enzymes: glutamate cysteine ligase and glutathione synthase).[2]
As well as acting as substrates from which GSH can be formed, glycine and cysteine also play their own role in many biochemical reactions, and thus should be kept at proper levels. Glycine contributes methyl groups (-CH3) to many chemical reactions (such as those involved in regulating gene expression), is a key component of cartilage, and is a neurotransmitter. Cysteine similarly donates sulfhydryl groups (-SH) to chemical reactions, binds to metal ions, and supports protein structure via the formation of disulfide bonds.[11][12]
What are other names for GlyNAC?
Note that GlyNAC is also known as:
- Glycine-NAC
- Glycine-N-Acetylcysteine
GlyNAC should not be confused with:
- NAC
- N-Acetylcysteine
- Glycine
Dosage information
The most common dosage in the (limited) body of research is 1.33 and 0.81 mmol/kg/day (millimoles per kilogram of bodyweight per day) of glycine and cysteine (in the form of n-acetylcysteine, which is about 74% cysteine), respectively. This dosage is equivalent to about 100 and 133 mg per kilogram of body weight per day (mg/kg/day) of glycine and n-acetylcysteine, respectively.
Frequently asked questions
What is GlyNAC?
What are GlyNAC’s main benefits?
Preliminary research suggests that GlyNAC may reduce oxidative stress and improve metabolic health in conditions characterized by high levels of oxidative stress, such as type 2 diabetes (T2D), human immunodeficiency virus (HIV), and aging.[2][3] As is the case with n-acetylcysteine, these benefits are largely brought about by increasing intracellular levels of the antioxidant glutathione.[4]
Before discussing specific outcomes, it’s worth underscoring that, as of 2024, most studies on GlyNAC follow the same general methodology. People in the treatment group, who all have some condition of interest (e.g., people with HIV, people with T2D, or older people), receive some quantity of GlyNAC daily; their biomarkers of oxidative stress and metabolic health are measured at baseline, after the treatment period, and several weeks after the treatment has ceased. These biomarkers are compared to those of a group without the condition of interest (e.g., people without HIV, people without T2D, or young people) who have not received the treatment. Generally speaking, GlyNAC is able to shift the biomarkers of the treatment group to more closely resemble (and sometimes equal) those of the non-treatment group, and these biomarkers then return to baseline (i.e., worsen) after treatment is discontinued. This study design is certainly useful, especially with small groups, but the literature would still benefit from more randomized controlled trials.
With respect to specific outcomes, GlyNAC seems able to improve (i.e., reduce) fasting respiratory quotient, glucose oxidation, insulin resistance, and plasma free fatty acids in people with T2D.[5][1]
In people with HIV, GlyNAC has been reported to improve fasting glucose levels, measures of oxidative stress like thiobarbituric acid reactive substances (TBARS) and F2-isoprostane, and scores on the physical and mental components of the SF-36, which evaluates quality of life.[6][3]
One randomized trial in healthy older adults found that GlyNAC didn’t always raise blood levels of glutathione sulfhydryl (GSH), the reduced form of glutathione, and that GlyNAC’s ability to do so may be dependent on a person’s baseline GSH status (i.e., people with low GSH may benefit from GlyNAC, while people with normal levels of GSH may not).[7]
Is taking GlyNAC better than taking NAC alone?
Theoretically, yes. Certain groups of people (such as older adults) can have both reduced glutathione levels and reduced cysteine and glycine levels.[14] Although both glycine and cysteine can be produced by the body, their levels seem to be highly influenced by diet, and it’s possible that endogenous production of these amino acids may not be sufficient in people with higher demand (such as people with high levels of oxidative stress).[15][16]
What are GlyNAC’s main drawbacks?
No notable side effects have been reported in the GlyNAC literature, although there have been some documented instances of NAC causing nausea, vomiting, and diarrhea.[8][9]
When NAC or GlyNAC are taken intravenously, NAC overdose is possible, and can result in red blood cell breakdown (hemolysis), low blood platelet count (thrombocytopenia), kidney failure, and possibly death.[10]
How does GlyNAC work?
GlycNAC is thought to provide its benefits largely by increasing the production of GSH. GlyNAC is simply glycine and cysteine (in the form of n-acetylcysteine), which are two of the three substrates necessary for the synthesis of GSH (via two enzymes: glutamate cysteine ligase and glutathione synthase).[2]
As well as acting as substrates from which GSH can be formed, glycine and cysteine also play their own role in many biochemical reactions, and thus should be kept at proper levels. Glycine contributes methyl groups (-CH3) to many chemical reactions (such as those involved in regulating gene expression), is a key component of cartilage, and is a neurotransmitter. Cysteine similarly donates sulfhydryl groups (-SH) to chemical reactions, binds to metal ions, and supports protein structure via the formation of disulfide bonds.[11][12]
What is the role of glutathione in the body?
Glutathione’s reduced form, GSH, is a relevant target for treatment because it’s one of the most critical endogenously-produced antioxidants in the body. GSH is found in high quantities in the fluid of the lungs, for example, where it helps reduce the reactive oxygen species produced by neutrophils responding to smoke and other oxidizing compounds you may inhale.[13] Within the cell, GSH helps to reduce reactive oxygen species, such as the superoxide and peroxide radicals. Additionally, it is found in many organelles, aiding in the regulation of mitochondrial life cycle and cell division.[13]
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