An Overlooked Amino Acid
Glycine: The Unsung Amino Acid Your Body Needs
When we think about nutrition, we often talk about protein, carbs, fats, vitamins, and minerals, and rightly so. But tucked quietly behind those headline nutrients is an amino acid that plays a surprisingly central role in our health: glycine.
Glycine is a non-essential amino acid, meaning our bodies can make it. But “can make it” does not mean make enough of it. Glycine is critically involved in functions as diverse as building healthy collagen, regulating blood sugar, supporting restful sleep, and protecting the nervous system. And because modern diets often emphasize muscle meat over whole, connective-tissue-rich foods, many people simply don’t get enough glycine from their food.
This article will walk you through what glycine does, why it matters, and how to incorporate it into your eating pattern in practical ways — without supplements or fads.
What Glycine Actually Does
At a biochemical level, glycine is an amino acid, one of the building blocks of protein. But its roles go far beyond just “making protein.” Unlike many amino acids that are primarily structural bricks, glycine functions in several key physiological systems:
Collagen and Connective Tissue
Glycine is required in large amounts to make collagen, the most abundant protein in the human body. Collagen forms the scaffolding of our skin, bones, tendons, ligaments, and blood vessels. If you imagine your body as a building, collagen is the rebar in the concrete. Without enough glycine, your body struggles to maintain that framework.
Metabolic Regulation
Glycine participates in gluconeogenesis, the process by which the body makes glucose from non-carbohydrate sources. This helps maintain stable blood sugar levels during fasting or between meals.
Detoxification and Antioxidant Support
Glycine is a component of glutathione, one of the body’s most important antioxidants. Glutathione helps neutralize free radicals and supports the liver in detoxification. Without sufficient glycine, glutathione production can be limited.
Brain and Nervous System Modulation
Unlike many amino acids that act as excitatory signals in the brain, glycine functions as an inhibitory neurotransmitter in certain parts of the central nervous system. That means it helps calm neural activity — which is why glycine has been studied for its effects on sleep quality and relaxation.
Why Modern Diets Can Be Low in Glycine
Traditional diets obtained glycine naturally from foods that many people now avoid or minimize: bone broths, skin-on poultry, organ meats, and connective tissues found in slow-cooked meats. As a result, people eating modern Western diets – where muscle meat is emphasized but connective tissue is discarded – may not get enough glycine, even if total protein intake is adequate.
This is not a “deficiency” in the clinical sense, but rather a nutrient gap that can quietly contribute to slower recovery, poorer sleep, and less resilient connective tissues over the long run.
Signs You Might Benefit from More Glycine
Because glycine participates in so many systems, deficiency doesn’t show up as a single dramatic symptom. Instead, you might notice:
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Trouble sleeping or frequent night wakings
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Persistent joint stiffness or slow recovery after physical activity
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Higher blood sugar swings between meals
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Suboptimal skin elasticity or slower wound healing
None of these alone is diagnostic of a glycine shortfall, but they are patterns worth noting in the context of overall diet.
Real-Food Ways to Increase Glycine
The best way to support glycine levels is through whole foods that naturally contain it. Here are practical ways to add glycine-rich foods to your meals:
Bone Broth
Simmering bones, skin, and connective tissue for many hours releases glycine and other amino acids into the broth. Use it as a base for soups or sip it warm.
Gelatin-Rich Foods
Gelatin, a cousin of collagen, is high in glycine. Traditional jellies, aspics, or homemade fruit gelatins made with grass-fed gelatin can be a nourishing addition.
Skin-on Poultry and Slow-Cooked Meats
Leaving the skin on chicken or slow-cooking cuts with connective tissue (like chuck roast or oxtail) increases the glycine content of your meal.
Organ Meats (Optional)
Liver, heart, and other organ meats contain glycine along with a range of micronutrients. If you’re new to organ meats, start with small amounts mixed into ground dishes.
Fish with Skin
The skin of salmon, trout, and other oily fish contains connective tissue that contributes glycine.
These foods aren’t trendy because they weren’t invented yesterday – they are time-tested parts of traditional eating patterns.
What the Science Says
Research on glycine has grown in recent years. For example, studies and reviews have noted glycine’s role in improving sleep quality, supporting metabolic health, and contributing to antioxidant and anti-inflammatory pathways. If you want a concise, science-focused overview of glycine’s roles, the U.S. National Institutes of Health has a useful reference page in its PubChem database:
➡️ https://pubchem.ncbi.nlm.nih.gov/compound/Glycine
That page links to biochemical data and peer-reviewed studies supporting glycine’s functions in human physiology.
Putting It into Practice the Century Living Way
Century Living Institute doesn’t chase quick fixes. We look at nourishment as what creation provided, interpreted through observation and applied with intention. That means making nutrient-dense foods part of your daily habits, not as a chore but as a rhythm that supports health over decades.
You don’t need to micromanage every gram of amino acid. Instead, start with meals that include whole proteins, skin and connective tissue, and slow-cooked broths – the foods our bodies recognize and have evolved to use.
Over time, paying attention to glycine isn’t about hitting a target number. It’s about listening to how your body recovers, sleeps, and responds to movement and stress, and letting that feedback guide your choices.
