There are so many options these days when it comes to sweetening your hot drinks or powdered supplements. Sugar, the most obvious candidate, comes with a blood glucose spike and many empty calories. Zero-calorie, artificial sweeteners can confuse the body and bring with them nasty chemicals and nastier consequences. Glycine, on the other hand, has no such cons or side effects to speak of. Glycine is the smallest of the amino acids, it is naturally sweet in taste, and may actually help stabilize blood sugar! It is not considered an essential amino acid because the body can make it, but only when you consume an adequate amount and the appropriate types of dietary protein. Supplementing with glycine ensures that there is an abundance of glycine available for all of its beneficial actions.

Glycine will sweeten your drink and help to keep you healthy by contributing to liver detoxification and regeneration, keep you aging gracefully by aiding in collagen and antioxidant production, keep you strong by aiding in muscle repair while supporting your joints and nerves, and keep you rested by promoting deep, restful sleep.

Where does Detoxification occur?

The liver is the body’s built-in detoxification system. Its job is to rid the body of toxins by breaking them down, conjugating them to bile, or sending them to the kidneys for excretion. The body’s strongest, most versatile conjugating substance is glutathione, and you can’t make glutathione without glycine; glycine is actually a rate-limiting factor in glutathione biosynthesis [1]. Most glutathione biosynthesis occurs in the liver, but the body’s stores can easily be drained. Benzoates (a food and soft drink additive) can bind glycine, depleting your body’s valuable glycine stores. Aspirin can also slow this detoxification pathway by competing for glycine in the liver. However, when glycine is abundant and glutathione stores are up, glutathione also circulates through the bloodstream combating free radicals. It provides general antioxidant protection from nonspecific oxidant damage, acts as an electron donor for glutathione peroxidase and glutaredoxin, and reverses prooxidative signaling that plays a prominent pathogenic role in many health disorders [1].

In addition to its role as a glutathione precursor, glycine is a substrate in the synthesis of heme (the non-protein portion of hemoglobin), purines, creatine, sarcosine, and bile salts [2].

Is Collagen made up of Amino Acids?

Glycine makes up about 1/3 of the amino acids in elastin and collagen, the most abundant protein in the human body. Therefore, glycine is a major component of connective tissues and the extracellular matrix [3]. As we get older, collagen production naturally declines, and with the loss of collagen comes the loosening of the skin, wrinkles, increased cellulite, joint pain, and difficulty gaining muscle and burning fat [4, 5, 6, 7]. Supplementing with glycine makes more substrate available to combat the natural loss of collagen to slow or prolong the development of these symptoms.

Do Joints need Glycine?

Aging and the loss of collagen are not the only causes of joint pain, but glycine may help to address these issues as well as a few others. Glycine is both a prominent structural component of healthy cartilage and connective tissue and a powerful anti-inflammatory through effects on immunomodulation and the down-regulation of pro-inflammatory activities [1]. Studies have also demonstrated that glycine supplementation was associated with a reduction of symptoms such as inflammation and swelling in some models of arthritis [8].

Although not technically a joint, a rat model of Achilles tendinitis demonstrated that supplemental glycine aided in healing [1].

Do Muscles and Bones need Glycine?

There’s even more to the physical benefits of glycine: twin studies have provided critical evidence for glycine’s role in bone health. Data show that although both twins have the same genetic makeup, the twin with higher dietary intake of glycine tends to have greater spinal bone mineral density [1].

Glycine contributes to the inhibition of muscular deterioration while boosting muscle recovery [9]. Recovery and re-building of new, stronger muscle happen in part due to the biosynthesis of creatine, for which glycine is an important component [10]. Glycine also helps provide cells with energy as it plays a role in the conversion of nutrients from your diet, ramping up production of ATP for working muscle tissues, boosting endurance, strength, and performance. It also has a beneficial effect on hormone production and regulation, contributing to the natural synthesis of steroid hormones that control how energy is allocated for use and regulate the ratio of fat to muscle mass [10].

How does Glycine affect our Nerves?

Glycine subserves both inhibitory and excitatory functions within the CNS [3]. In the brainstem and spinal cord, glycine acts as a calming neurotransmitter, similar to GABA. In fact, it is co-released with GABA to inhibit parts of the central nervous system. It participates in the processing of motor and sensory information related to movement, vision, and auditory transmission [2]. In the forebrain, glycine modulates excitatory neurotransmissions as well by potentiating the action of glutamate at N-methyl-D-aspartate (NMDA) receptors [2,3]. This unique neurotransmitter also helps with sleep, memory, mental performance, stress, anxiety, and even severe mental illness [11].

What Natural Product can I use to help me Sleep?

When volunteers who had been suffering from insomnia were given 3 grams of glycine before bedtime, their sleep improved [12]. Polysomnography, a sleep diagnostic tool, showed that glycine supplementation shortened the amount of time it took for them to fall asleep and stabilize their sleep state, without altering sleep architecture [12]. Metabolic Maintenance’s Glycine Sticks are packaged in 3-gram portions based on the positive results of this study.

Oral supplementation of glycine can readily cross the blood-brain barrier via glycine transporters [13]. In the brain, glycine targets glutamate NMDA receptors in the suprachiasmatic nucleus (SCN), which is the 24-hour biological clock in the central nervous system that controls when we should be asleep and when we should be awake. Through this pathway, glycine induces vasodilation throughout the body which leads to lowering the core body temperature (thermoregulation) which is an important step for initiating sleep.

Glycine won’t make you sleepy in the daytime though. It activates another element of the SCN that stimulates wakefulness. Glycine upregulates expression of arginine vasopressin, which ultimately leads to the production of cortisol in the adrenal glands, thereby promoting alertness in the day [14].

Talk to your doctor about how you may benefit from adding glycine sticks to your nutritional regimen. A little bit of sweet may make a big difference in your health!


  1. McCarty, Mark F., James H. O’Keefe, and James J. DiNicolantonio. “Dietary glycine is rate-limiting for glutathione synthesis and may have broad potential for health protection.” The Ochsner Journal 18.1 (2018): 81.
  2. Lopez-Corcuera, Beatriz, Arjan Geerlings, and Carmen Aragon. “Glycine neurotransmitter transporters: an update.” Molecular membrane biology 18.1 (2001): 13-20.
  3. Paul, Steven. “GABA and Glycine”.  American College of Neuropsychopharmacology. Accessed Feb 21, 2019.
  4. Proksch, E., et al. “Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study.” Skin pharmacology and physiology 27.1 (2014): 47-55.
  5. Schunck, Michael, et al. “Dietary supplementation with specific collagen peptides has a body mass index-dependent beneficial effect on cellulite morphology.” Journal of medicinal food 18.12 (2015): 1340-1348.
  6. Crowley, David C., et al. “Safety and efficacy of undenatured type II collagen in the treatment of osteoarthritis of the knee: a clinical trial.” International journal of medical sciences 6.6 (2009): 312.
  7. Zdzieblik, Denise, et al. “Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial.” British Journal of Nutrition 114.8 (2015): 1237-1245.
  8. Razak, Meerza Abdul, et al. “Multifarious beneficial effect of nonessential amino acid, Glycine: a review.” Oxidative medicine and cellular longevity 2017 (2017).
  9. Ham, Daniel J., et al. “Glycine administration attenuates skeletal muscle wasting in a mouse model of cancer cachexia.” Clinical nutrition 33.3 (2014): 448-458.
  10. Arwert, Lucia I., Jan Berend Deijen, and Madeleine L. Drent. “Effects of an oral mixture containing glycine, glutamine and niacin on memory, GH and IGF-I secretion in middle-aged and elderly subjects.” Nutritional neuroscience 6.5 (2003): 269-275.
  11. Wood, Amber. “Glycine or Collagen?” AmberWood Health. October 17, 2018.
  12. W.I. Yamadera, K.; Chiba, S.; Bannai, M.; Takahashi, M., Nakayama, K., Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes, Sleep and Biological Rhythms 5 (2007).
  13. A. Kurolap, A. Armbruster, T. Hershkovitz, K. Hauf, A. Mory, T. Paperna, E. Hannappel, G. Tal, Y. Nijem, E. Sella, M. Mahajnah, A. Ilivitzki, D. Hershkovitz, N. Ekhilevitch, H. Mandel, V. Eulenburg, H.N. Baris, Loss of Glycine Transporter 1 Causes a Subtype of Glycine Encephalopathy with Arthrogryposis and Mildly Elevated Cerebrospinal Fluid Glycine, Am J Hum Genet 99(5) (2016) 1172-1180.
  14. H.K. Caldwell, E.A. Aulino, K.M. Rodriguez, S.K. Witchey, A.M. Yaw, Social Context, Stress, Neuropsychiatric Disorders, and the Vasopressin 1b Receptor, Front Neurosci 11 (2017) 567.