What is GlyNAC? Effects, benefits, dosage, and research

Short answer: GlyNAC is a combination of glycine and N-acetylcysteine (NAC). Both provide building blocks that the body uses to produce glutathione (GSH), an antioxidant that the body produces itself.

GlyNAC is primarily studied in older adults in relation to glutathione status, oxidative stress, and various metabolic and functional outcomes. Small human studies show positive results, but the total evidence is still limited. GlyNAC is not a proven anti-aging treatment, and there is no evidence that it extends lifespan.

GlyNAC in brief

Question Short answer
What is GlyNAC? A combination of glycine and N-acetylcysteine (NAC).
How does GlyNAC work? Glycine and NAC provide building blocks for the body’s own production of glutathione.
What is it being researched for? Including glutathione status, oxidative stress, and various metabolic and functional outcomes in older adults.
Is the effect proven? There are positive small human studies, but the total clinical evidence is still limited.
What is the correct dosage? Various dosages have been used in studies. There is no universal GlyNAC dosage.
Is GlyNAC safe? Short-term human studies suggest reasonable tolerability; data on long-term daily use are more limited.

How does GlyNAC work in the body?

Your body produces glutathione (GSH) itself from three amino acids: glycine, cysteine, and glutamate. GlyNAC provides two relevant parts of this pathway: glycine directly and NAC as a source of cysteine.

Glycine → building block of glutathione
NAC → source of cysteine → building block of glutathione
Glycine + cysteine + glutamate → glutathione (GSH)

Glutathione plays a role in protecting cells against oxidative stress and in various cellular processes. Cysteine can be a limiting building block in this process. NAC is therefore used as a source that can support the availability of cysteine.

Why GlyNAC and not just NAC?

The production of glutathione requires not just one, but several amino acids. NAC provides a source of cysteine, while GlyNAC also provides glycine.

That mechanism explains why GlyNAC is being researched in relation to glutathione status and oxidative stress. However, a biologically plausible mechanism does not automatically mean that a supplement also provides proven health benefits.

GlyNAC infographic with glycine and NAC: explanation of mechanism via glutathione and oxidative stress.

1. Building blocks

GlyNAC stands for glycine + N-acetylcysteine (NAC). Glycine is itself a building block of glutathione. NAC can contribute to the availability of cysteine.

2. Glutathione

With glycine, cysteine, and glutamate, the body can produce glutathione (GSH). GlyNAC therefore focuses on the availability of two of these building blocks.

3. Research

GlyNAC is being studied in humans in relation to, among other things, glutathione status, oxidative stress, and various metabolic and functional outcomes. The current evidence is interesting but still limited.

What does scientific research say about GlyNAC?

Human research into GlyNAC focuses primarily on older adults. Positive results have been published, but the number of studies and participants is still limited. Furthermore, several positive studies come from the same research group. Therefore, more independent and large-scale research is needed.

Study Design Duration Researched Context
Kumar et al. Randomized clinical trial in older adults 16 weeks Glutathione, oxidative stress, and various metabolic and functional outcomes Positive findings on multiple researched outcomes; small study.
Sekhar et al. Pilot study in older adults 24 weeks Glutathione and multiple biological and functional outcomes Positive results, but a small pilot study.
McCaddon et al. Randomized study in healthy older adults 2 weeks Glutathione redox status and oxidative damage Not all researched outcomes showed a significant effect; short study duration.

Important: positive results from small studies are not the same as proof that GlyNAC prevents disease, slows down aging, or extends lifespan.

What are the possible benefits of GlyNAC?

GlyNAC is primarily researched because of the role of glycine and cysteine in the production of glutathione. In small studies in older adults, the following topics have been investigated, among others:

  • glutathione status;
  • oxidative stress;
  • mitochondrial function;
  • inflammatory markers;
  • metabolic outcomes;
  • some measures of physical function.

Some studies reported improvements in multiple outcomes. However, the number of human studies is small, the research groups are limited, and a significant portion of the positive research comes from the same research group.

The results can therefore not simply be translated to all healthy adults or be seen as proof that GlyNAC prevents aging.

GlyNAC dosage: how much per day?

Various dosage protocols have been used in human studies. In an important study in older adults, participants received:

100 mg/kg/day glycine + 100 mg/kg/day NAC.

In another study in healthy older adults, total daily dosages were tested of:

  • 2.4 grams per day;
  • 4.8 grams per day;
  • 7.2 grams per day.

These are research dosages and not personal dosing advice. There is currently no universal GlyNAC dosage that applies to everyone.

More information can be found in our detailed explanation of GlyNAC dosage and use.

When is the best time to take GlyNAC?

There is no convincing evidence that one specific time is optimal for everyone. In practice, GlyNAC is often taken daily.

NAC can cause gastrointestinal complaints in some people. Taking it around a meal may therefore be more pleasant for some users.

Are you taking medication, are you pregnant, breastfeeding, or do you have a medical condition? Then consult a doctor or pharmacist first before using a supplement with NAC.

GlyNAC side effects

GlyNAC is generally described in short-term human studies as being reasonably well tolerated. Possible complaints are partly related to the NAC component.

Possible complaints include:

  • stomach upset;
  • intestinal complaints;
  • nausea.

Whether and to what extent someone experiences side effects can vary per person and dosage.

Read more about possible GlyNAC side effects and points of attention.

Is GlyNAC safe?

Based on current human studies, GlyNAC generally appears to be reasonably well tolerated with short-term use. Data on long-term daily use are more limited.

Because GlyNAC contains NAC, the safety information about NAC is also relevant. The RIVM has published a risk assessment on food supplements containing N-acetylcysteine.

Who should be extra careful?

Consult a doctor, pharmacist, or other qualified healthcare professional when you:

  • use medication;
  • are pregnant or breastfeeding;
  • have surgery planned;
  • have a medical condition;
  • are unsure if NAC is suitable in your situation.

GlyNAC versus other supplements

What is the difference between GlyNAC and NAC?

NAC is used as a source for cysteine. GlyNAC combines NAC with glycine and thereby provides two building blocks that are relevant for the body’s own production of glutathione.

Read the detailed comparison: GlyNAC vs NAC: what is the difference?

GlyNAC versus glutathione

GlyNAC does not contain glutathione itself. It is a precursor strategy: glycine and NAC provide raw materials that the body can use for its own glutathione production.

GlyNAC versus NMN

GlyNAC and NMN target different biological pathways. GlyNAC is primarily studied in relation to glutathione and oxidative stress. NMN is a precursor of NAD+ and is studied from that biological pathway.

There is no strong direct human evidence showing that GlyNAC is better than NMN or vice versa.

Also read: NMN, TMG and GlyNAC explained at the cellular level.

What should you look for in a GlyNAC supplement?

If you want to compare a GlyNAC supplement, don’t just look at the front of the label. Pay attention to, among other things:

  • the amount of glycine per dose;
  • the amount of NAC per dose;
  • the ratio between glycine and NAC;
  • a transparent list of ingredients;
  • clear usage information;
  • quality and purity.

View our GlyNAC capsules for the current composition and usage information.

How long does it take for GlyNAC to work?

There is no generally proven duration after which someone should experience a noticeable effect from GlyNAC.

The most important human studies looked at changes over a period of weeks. For example, one of the randomized trials in older adults lasted 16 weeks.

Furthermore, research results on biomarkers or functional outcomes do not automatically mean that every user will experience a noticeable effect themselves.

How strong is the evidence for GlyNAC?

The biological mechanism behind GlyNAC is well-explained: glycine and cysteine are building blocks that the body uses for the production of glutathione. In addition, there are human studies in which positive changes have been measured.

At the same time, the clinical evidence is still limited. There are relatively few studies, research groups are small, and long-term data are largely lacking. Not every study found a significant effect on all researched outcomes.

There is currently no evidence that GlyNAC prevents aging or extends lifespan.

GlyNAC can therefore best be seen as a combination with a biologically explainable mechanism and initial human research results, but for which more independent and large-scale research is needed.

Terms related to GlyNAC and glutathione

GSH (glutathione)
The reduced form of glutathione and an important antioxidant in the body.

GSSG
The oxidized form of glutathione.

NAC
N-acetylcysteine; used as a source for cysteine.

Cysteine
One of the three amino acids from which glutathione is built.

Glycine
An amino acid and building block of glutathione.

Glutamate
The third amino acid building block of glutathione.

ROS
Reactive oxygen species involved in oxidative processes.

Oxidative stress
A disruption of the balance between oxidative processes and antioxidant defense.

GPx
Glutathione peroxidase; an enzyme that uses glutathione in the conversion of certain peroxides.

GR
Glutathione reductase; involved in the regeneration of reduced glutathione.

Frequently asked questions about GlyNAC

What is GlyNAC?

GlyNAC is the combination of glycine and N-acetylcysteine (NAC). Glycine is an amino acid and NAC can serve as a source for cysteine. Glycine and cysteine are both building blocks of glutathione.

How does GlyNAC work?

The body produces glutathione itself from glycine, cysteine, and glutamate. GlyNAC provides glycine and supports the availability of cysteine via NAC.

What does research say about GlyNAC?

There are small human studies, primarily in older adults. These have investigated glutathione status, oxidative stress, and various metabolic and functional outcomes, among other things. Some studies reported positive results, but the research is still limited and more independent research is needed.

What is the best GlyNAC dosage?

There is no universal, scientifically established GlyNAC dosage for everyone. Studies have used different dosages. Read more about the researched GlyNAC dosages.

When is the best time to take GlyNAC?

There is insufficient evidence that one specific time is optimal. NAC can cause gastrointestinal complaints in some people, so taking it around a meal can sometimes be more pleasant.

What is the difference between GlyNAC and NAC?

NAC provides a source for cysteine. GlyNAC combines NAC with glycine and thus provides two building blocks that are relevant for glutathione production. Read the full comparison between GlyNAC and NAC.

Does GlyNAC have side effects?

Possible complaints can include gastrointestinal issues and nausea. The reaction can vary per person and dosage. Read more about GlyNAC side effects and safety.

Can GlyNAC counteract aging?

There is currently no evidence that GlyNAC prevents aging or extends human lifespan. The supplement is being researched in relation to biological processes that change during aging.

Where can you buy GlyNAC?

At Every Day Better you will find GlyNAC capsules. Always check the composition, dosage, and warnings on the label before use.

Scientific sources

  1. Kumar P, Liu C, Suliburska J, et al. Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Physical Function, and Aging Hallmarks: A Randomized Clinical Trial. The Journals of Gerontology: Series A. View study via PubMed.
  2. Sekhar RV, Patel SG, Guthikonda AP, et al. Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Insulin Resistance, Endothelial Dysfunction, Genotoxicity, Muscle Strength, and Cognition: Results of a Pilot Clinical Trial. Clinical and Translational Medicine. View study via PubMed.
  3. McCaddon A, Regland B, Hudson P, Davies G. A Randomized Controlled Clinical Trial in Healthy Older Adults to Determine Efficacy of Glycine and N-Acetylcysteine Supplementation on Glutathione Redox Status and Oxidative Damage. Frontiers in Aging. View the study.
  4. RIVM. Risk assessment of food supplements containing N-acetylcysteine (NAC). National Institute for Public Health and the Environment. View the risk assessment.