"Glycine, the smallest amino acid, plays an essential role in multiple physiological processes and has gained attention for its anti-inflammatory properties and ability to slow aging."

Dr. Joseph Mercola

How Glycine Supports Longevity: The Science

1. Glycine May Help Extend Lifespan

One of the most compelling findings comes from studies on mice, where glycine supplementation has been shown to increase median lifespan by up to 6% (Miller et al., 2019). While this may seem modest, even small increases in lifespan at a cellular level can translate to significant long-term benefits in humans.

How does glycine extend lifespan?

  • Mimics Methionine Restriction: Methionine, an essential amino acid, is required for many biological processes, but excessive levels have been linked to accelerated aging. Glycine has been found to counteract methionine toxicity, potentially providing similar benefits to methionine restriction, which is a well-established longevity intervention (Liu et al., 2018).
  • Enhances Mitochondrial Function: Mitochondria—the “powerhouses” of our cells—play a critical role in aging. Glycine supplementation has been shown to restore mitochondrial efficiency in aging cells, boosting energy production and reducing oxidative stress (Brind et al., 2018).

2. Glycine Fights Inflammation and Oxidative Stress

Chronic inflammation and oxidative stress are two of the biggest contributors to aging and age-related diseases. Glycine has been shown to modulate inflammation and enhance antioxidant defenses, particularly through its role in glutathione production.

  • Glutathione Support: Glutathione is the body’s most powerful antioxidant, responsible for neutralizing free radicals and protecting cells from damage. Glycine is a key building block of glutathione, and supplementing with glycine (along with N-acetylcysteine in GlyNAC) has been shown to increase glutathione levels, reduce oxidative stress, and improve mitochondrial function in older adults (Kumar et al., 2022).
  • Anti-Inflammatory Mechanisms: Glycine activates glycine-gated chloride channels, which help suppress excessive immune responses and prevent chronic inflammation (Wheeler et al., 1999). This can be particularly beneficial for metabolic health, cardiovascular function, and neuroprotection.

3. Glycine Supports Brain Health and Cognitive Function

Cognitive decline is one of the most feared aspects of aging, but glycine may offer some protection against memory loss and neurodegeneration.

  • Enhances Memory and Learning: Glycine acts as a co-agonist at NMDA receptors, which play a crucial role in synaptic plasticity, memory formation, and cognitive function. Studies have found that glycine supplementation improves memory retrieval and attention in middle-aged and older adults (File et al., 1999).
  • May Protect Against Neurodegeneration: Glycine's ability to reduce oxidative stress and inflammation suggests it may have potential neuroprotective benefits, though more research is needed to confirm its role in conditions like Alzheimer’s and Parkinson’s.

4. Glycine Supports Skin, Hair, and Collagen Production

Collagen is the most abundant protein in the body, and it’s essential for maintaining skin elasticity, joint health, and connective tissues. Glycine is a primary building block of collagen, meaning it plays a direct role in keeping skin firm, hydrated, and youthful.

  • Boosts Skin Elasticity: Glycine is essential for collagen biosynthesis, which declines with age. Higher glycine intake supports skin hydration and reduces the appearance of fine lines.
  • Promotes Wound Healing: Studies suggest that glycine accelerates tissue repair by enhancing collagen synthesis and reducing inflammation in wounds and injuries (Pérez-Torres et al., 2016).

5. Glycine Enhances Metabolic Health and Muscle Function

Muscle loss (sarcopenia) and metabolic dysfunction are major concerns as we age, but glycine may help maintain muscle mass and support insulin sensitivity.

  • Supports Muscle Growth and Strength: Glycine is involved in protein synthesis, making it essential for muscle maintenance and recovery. In older adults, GlyNAC supplementation has been shown to improve muscle strength, gait speed, and endurance (Kumar et al., 2021).
  • Improves Insulin Sensitivity: Glycine has been linked to better glucose regulation, potentially reducing the risk of insulin resistance and metabolic disorders (Sekhar et al., 2019).

6. Glycine and Sleep: A Natural Ally for Restorative Slumber

Sleep is a critical component of longevity and overall well-being, influencing everything from cognitive function to metabolic health. Emerging research suggests that glycine plays a significant role in improving sleep quality, efficiency, and next-day cognitive performance. Unlike traditional sleep aids, glycine works naturally with the body's sleep-wake cycle, offering a gentle yet effective approach to restorative sleep.

Scientific studies have shown that glycine supplementation before bedtime can improve subjective and objective sleep quality. One study found that participants who took 3 grams of glycine before bed reported feeling more refreshed upon waking, less fatigued, and more clear-headed the next day (Yamadera et al., 2007). Additionally, polysomnographic data confirmed that glycine helps shorten the time it takes to fall asleep and enhances slow-wave sleep, the deep, restorative stage crucial for cellular repair and memory consolidation.

The mechanisms behind glycine’s sleep-enhancing effects include its ability to lower core body temperature, a key signal for initiating sleep. Glycine increases cutaneous blood flow, allowing excess heat to dissipate and promoting faster sleep onset (Bannai & Kawai, 2012). Additionally, glycine acts as a neurotransmitter that modulates the NMDA receptors in the brain, influencing sleep architecture and contributing to more efficient, deeper sleep cycles (Kawai et al., 2015).

Beyond just improving sleep itself, glycine also helps combat daytime fatigue and cognitive sluggishness associated with sleep deprivation. One study on sleep-restricted individuals found that glycine improved daytime alertness, reaction times, and memory performance, suggesting it could be beneficial for those with disrupted sleep schedules or occasional insomnia (Bannai et al., 2012).

By supporting deeper, more restorative sleep, glycine contributes to better cognitive function, metabolic regulation, and overall longevity—reinforcing its status as a key nutrient for optimal health and vitality.

Conclusion: Glycine’s Role in Longevity and Optimal Health

Glycine is far more than just a simple amino acid—it’s a key player in aging, cellular health, and overall longevity. Whether through enhancing mitochondrial function, reducing inflammation, protecting the brain, or supporting collagen synthesis, glycine offers a science-backed approach to aging well.

By incorporating glycine into a longevity-focused lifestyle, individuals may optimize their healthspan, improve cellular resilience, and maintain vitality well into later life.

As research continues to unfold, glycine is emerging as a foundational nutrient for longevity—a small molecule with big benefits.

How Glycine Impacts Aging:

Specific Hallmarks:

  • Mitochondrial Dysfunction – Glycine improves mitochondrial function by restoring glutathione levels and enhancing cellular energy production, which declines with age (Sekhar et al., 2022).
  • Genomic Instability – As a precursor to glutathione, glycine protects DNA from oxidative damage, potentially reducing mutations and maintaining genome integrity (Sekhar et al., 2022).
  • Loss of Proteostasis – Glycine plays a role in protein synthesis and repair, supporting cellular homeostasis and reducing misfolded protein accumulation, which contributes to aging (Sekhar, 2021).
  • Inflammation & Altered Intercellular Communication – Glycine modulates immune response and acts as an anti-inflammatory agent by interacting with glycine-gated chloride channels, reducing chronic low-grade inflammation linked to aging (Sekhar et al., 2021).

Mechanism of Action:

  • Improved Sleep – Glycine regulates the sleep-wake cycle, leading to better sleep quality and faster sleep onset, without causing drowsiness the next day (Yamadera et al., 2007).
  • Cognitive Support – As a key neurotransmitter modulator, glycine enhances memory, learning, and mental clarity, making it beneficial for cognitive longevity (File et al., 1999).
  • Metabolic Health – Glycine helps regulate blood sugar levels and improve insulin sensitivity, supporting metabolic function as we age (Sekhar et al., 2019).
  • Joint & Skin Health – As a primary building block of collagen, glycine promotes joint flexibility and skin elasticity, helping maintain a youthful appearance (Pérez-Torres et al., 2016).

Muscle Strength & Recovery – Glycine enhances muscle repair and reduces age-related muscle loss, supporting mobility and strength in aging populations (Kumar et al., 2021).

Scientific studies

  • Reference link

    ​​ Glycine Extends Lifespan by Regulating the Methionine Cycle

    Researchers found that glycine supplementation significantly prolonged the lifespan of C. elegans by feeding into the methionine cycle, a key regulator of cellular aging. Through transcriptomic analysis, they observed that glycine not only suppressed aging-related gene expression changes but also improved metabolic efficiency. The lifespan-extending effects were completely abolished when critical methionine cycle enzymes were mutated, confirming that glycine’s longevity benefits are mediated through this pathway. These findings suggest that glycine may play a crucial role in amino acid-mediated lifespan extension and could be a promising target for anti-aging interventions in humans. Published in PLoS Genetics (2018), titled “Glycine promotes longevity in Caenorhabditis elegans in a methionine cycle-dependent fashion” by Liu et al.

  • Reference link

    Glycine Supplementation Increases Lifespan in Mice

    Scientists tested whether dietary glycine supplementation could extend lifespan in genetically diverse mice. Mice fed an 8% glycine diet showed a 4-6% increase in lifespan, along with improved metabolic health and reduced risk of lung cancer. Unlike methionine restriction, glycine supplementation did not cause weight loss, making it a practical longevity intervention. The study suggests that modulating dietary amino acid levels can promote healthy aging, supporting the idea that glycine has lifespan-extending properties in mammals. Published in Aging Cell (2019), titled “Glycine supplementation extends lifespan of male and female mice” by Miller et al.

  • Reference link

    GlyNAC Improves Aging Hallmarks in Older Adults

    This randomized clinical trial evaluated the effects of GlyNAC supplementation in older adults over 16 weeks. The study found that GlyNAC corrected glutathione deficiency, improved mitochondrial function, reduced oxidative stress, and decreased inflammation. Participants also experienced enhanced physical function, cognitive performance, and metabolic health. These results highlight GlyNAC’s ability to reverse multiple aging-related defects, positioning it as a potential nutritional strategy for longevity and healthy aging. Published in The Journals of Gerontology: Series A (2022), titled “Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Aging Hallmarks” by Kumar et al.

  • Reference link

    Glycine Enhances Sleep Quality and Cognitive Function

    In a human clinical trial, researchers explored glycine’s effects on sleep and cognitive performance. Participants who took 3 grams of glycine before bedtime fell asleep faster, experienced deeper sleep, and reported feeling more refreshed upon waking. The study also found that glycine enhanced next-day cognitive function and reduced fatigue, making it a natural, non-habit-forming sleep aid with cognitive benefits. Published in Sleep and Biological Rhythms (2007), titled “Glycine ingestion improves subjective sleep quality in human volunteers” by Yamadera et al.

  • Reference link

    Beta-hydroxybutyrate (BHB) as an anti-aging substance

    BHB is a signaling molecule that modulates lipolysis, oxidative stress, and neuroprotection. It serves as an energy substrate for maintaining metabolic homeostasis. It delays many age-related disorders by acting as an epigenetic regulator of histone methylation, acetylation, and beta-hydroxybutyrylation. Additionally, research suggests that exogenous supplementation or endogenous BHB administration successfully induces an ametabolic state of nutritional ketosis (13, 23).

Recommended Dosage

2.5-5 g

per day

Estimated Amount Needed

~1

pound of fish

Source and origin

Glycine is naturally abundant in protein-rich foods, particularly in animal products such as meat, fish, eggs, and collagen-rich sources like bone broth and gelatin. It can also be found in smaller amounts in plant-based foods like legumes, seeds, and spinach. 

People Also Ask

  • Can glycine be used as a standalone supplement for anti-aging?

    While glycine offers significant benefits, it works best as part of a comprehensive protocol that addresses multiple aging mechanisms.

  • Does glycine have any known side effects?

    Glycine is generally well-tolerated at recommended doses, but excessive intake may cause mild gastrointestinal discomfort in some individuals.

  • How does glycine compare to other amino acids for longevity?

    Unlike some amino acids, glycine uniquely supports both structural health (through collagen) and metabolic regulation (through glutathione synthesis and methionine restriction effects).

  • Can glycine supplementation help with weight management?

    Glycine may indirectly support weight management by improving insulin sensitivity and regulating glucose metabolism, which are key factors in metabolic health.

  • Does glycine help with muscle recovery and performance?

    Yes, glycine supports muscle recovery by reducing inflammation, promoting protein synthesis, and enhancing mitochondrial efficiency.

  • Can glycine improve skin health?

    Glycine is essential for collagen production, which helps maintain skin elasticity, reduce wrinkles, and improve overall skin texture.

  • How long does it take to see benefits from glycine supplementation?

    Some benefits, like improved sleep quality, may be noticeable within days, while others, such as enhanced collagen synthesis and metabolic health, may take weeks to months of consistent use.

References

  • Reference link

    Bannai, M., & Kawai, N. (2012). New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep. Frontiers in Neurology, 3, 1-5.

  • Reference link

    Brind, J., Miller, R., & Harrison, D. (2018). Dietary glycine supplementation extends lifespan of male and female mice. Aging Cell, 17(3), e12739.

  • Reference link

    File, S. E., Fluck, E., & Fernandes, C. (1999). Beneficial effects of glycine (Bioglycin) on memory and attention in middle-aged and elderly individuals. Psychopharmacology, 142(4), 416-422.

  • Reference link

    Kawai, N., Sakai, N., et al. (2015). The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus. Neuroscience Letters, 591, 234-239.

  • Reference link

    Kumar, P., Liu, C., Suliburk, J., Hsu, J. W., Muthupillai, R., Jahoor, F., Minard, C., Taffet, G., & Sekhar, R. (2022). Supplementing GlyNAC in aging improves glutathione, mitochondria, and aging hallmarks: A randomized clinical trial. Innovation in Aging, 6, 98-98.

  • Reference link

    Liu, C., Janssens, G. E., et al. (2018). Glycine promotes longevity in Caenorhabditis elegans in a methionine cycle-dependent manner. Nature Communications, 9(1), 5076.

  • Reference link

    Miller, R. A., Harrison, D. E., et al. (2019). Glycine supplementation extends lifespan of male and female mice. Aging Cell, 18(4), e12953

  • Pérez-Torres, I., Zúñiga-Muñoz, A. M., & Guarner-Lans, V. (2016). Beneficial effects of the amino acid glycine. Mini Reviews in Medicinal Chemistry, 16(1), 1-9.

  • Reference link

    Sekhar, R. (2021). GlyNAC supplementation improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, aging hallmarks, metabolic defects, muscle strength, cognitive decline, and body composition: Implications for healthy aging. The Journal of Nutrition.

  • Reference link

    Wheeler, M. D., Ikejema, K., et al. (1999). Glycine: A new anti-inflammatory immunonutrient. Journal of Nutrition, 129(4), 1082-1089.

  • Reference link

    Yamadera, W., Inagawa, K., et al. (2007). Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes. Sleep and Biological Rhythms, 5(2), 126-131.

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