How Glycine Fixes Sleep Without Drugs | Mercola Cellular Wisdom

Indexed: 2026-05-19

[00:00:00]What if one of the most important molecules in your body has been hiding in plain sight for over 200 years, dismissed as non-essential while quietly holding together your collagen, your sleep cycles, and your ability to detoxify?

[00:00:12]Glycine is the smallest amino acid in nature, and for decades the medical establishment labeled it something your body makes enough of on its own.

[00:00:21]Dr. Mercola says that classification may be one of the biggest oversights in nutritional science.

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[00:00:45]Hello and welcome to Dr. Mercola's Cellular Wisdom. Glycine was first discovered in 1820.

[00:00:51]Because the body can synthesize it from another amino acid called serine, it earned the label non-essential.

[00:00:57]But Dr. Mercola points out a critical gap in that logic.

[00:01:02]The body produces roughly 3 g of glycine per day through an enzyme called serine hydroxymethyltransferase.

[00:01:09]The actual metabolic demand, however, is somewhere between 10 and 13 g per day.

[00:01:13]That is a 7-to-10 g deficit that has to come from food. When it does not, every system that depends on glycine starts to feel the strain.

[00:01:22]This is not a minor shortfall. It is a daily compounding nutritional gap that most people do not even know they have.

[00:01:29]The collagen connection alone makes the case.

[00:01:32]Glycine makes up roughly 1/3 of all the amino acids in collagen, appearing as every third residue in the repeating sequence that gives collagen its triple helix structure.

[00:01:42]Without adequate glycine, collagen synthesis falters.

[00:01:47]Dr. Mercola explains that this directly affects skin elasticity, joint integrity, wound healing, and even the structural soundness of your blood vessels. People spending money on collagen supplements while eating glycine-depleted diets may be undermining their own investment. If the raw material is missing, the assembly line cannot run.

[00:02:05]It is like buying lumber but having no nails. But glycine's role extends far beyond structural support.

[00:02:11]Dr. Mercola highlights its function as a precursor for glutathione, which the body uses as its master antioxidant.

[00:02:19]Glycine combines with cysteine and glutamate to form this critical molecule.

[00:02:24]It also participates directly in phase two detoxification in the liver through a process called glycine conjugation, where it binds to toxins, drugs, and metabolic waste products so they can be safely excreted. If your glycine levels are low, both of these detoxification pathways are compromised. Your body's ability to neutralize free radicals and clear harmful substances becomes bottlenecked at one of the most fundamental levels of cellular defense.

[00:02:50]The sleep research is particularly fascinating.

[00:02:52]A team at Ajinomoto and Stanford University's Sleep and Circadian Neurobiology Laboratory found that 3 g of glycine taken before bed drops core body temperature by activating NMDA receptors in the suprachiasmatic nucleus.

[00:03:07]That temperature drop is the biological trigger that initiates sleep onset. Dr. Mercola emphasizes that unlike sedative sleep aids, glycine does not cause morning grogginess.

[00:03:17]Subjects in the research reported feeling more refreshed, more alert, and less fatigued the following day.

[00:03:23]It works with the body's own circadian mechanism rather than overriding it. Dr. Mercola also draws attention to glycine's anti-inflammatory properties, which operate through a mechanism most people have never heard of.

[00:03:35]Glycine activates chloride channels on immune cells, specifically macrophages and neutrophils.

[00:03:42]When these channels open, the cells become hyperpolarized, which reduces their production of inflammatory signaling molecules, including TNF and interleukin 6.

[00:03:51]This is not a drug effect. It is a direct receptor-mediated biological response. There is also emerging evidence connecting glycine to blood sugar regulation. Studies show that glycine supplementation supports healthy insulin sensitivity and helps maintain blood sugar markers already within the normal range.

[00:04:09]The proposed mechanism involves enhanced insulin secretion through GLP-1 stimulation and improved glucose uptake in muscle tissue. Dr. Mercola notes that this makes glycine relevant to metabolic health in ways that most people never consider when they hear the word amino acid. It is not just a building block.

[00:04:27]It is an active participant in how the body manages energy and fuel. The neuroprotective angle is equally compelling. Glycine functions as an inhibitory neurotransmitter in the brainstem and spinal cord through glycine receptors while simultaneously acting as a co-agonist at NMDA receptors in the brain.

[00:04:44]This dual role gives it influence over both calming and excitatory neural pathways. Dr. Mercola explains that glycine also participates in one-carbon metabolism through the glycine cleavage system feeding methyl groups into the folate cycle. So, where do you actually get enough glycine from food?

[00:05:02]Dr. Mercola recommends bone broth as the single best whole food source providing 3 to 5 g of glycine per cup.

[00:05:10]Other rich sources include collagen-dense cuts of meat such as skin and connective tissue, gelatin, pork skin, chicken skin, and fish skin.

[00:05:19]These are precisely the parts of the animal that modern diets have largely abandoned in favor of lean muscle meats.

[00:05:25]For sleep support, Dr. Mercola suggests 3 to 5 g of glycine before bed.

[00:05:30]For broader collagen and detoxification support, intakes of up to 10 to 15 g per day are discussed in the literature and glycine has an excellent safety profile with minimal side effects even at those higher amounts. This is a molecule that costs very little, has virtually no downside, and touches nearly every major system in the body.

[00:05:49]Head to mercola.com to read the full article on glycine and its role as a foundational molecule in human health.

[00:05:57]Drop a comment below and tell us, are you getting enough glycine in your diet or has this been a blind spot for you?

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