Glycine: The Overlooked Amino Acid That Does Way More Than You Think

And the Importance of Drinking Bone Broth Soup

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If there were a quiet overachiever in human biology, it would be glycine.

It doesn’t get the spotlight like collagen, creatine, or glutathione, yet without glycine, you wouldn’t have them. It doesn’t get marketed like trendy supplements, yet your sleep, skin, liver, brain, heart, and joints depend on it.

First: What Is Glycine?

While glycine is technically a “non-essential” amino acid because your body can make it, primarily through serine, certain phsyiological demands like rapid growth, aging, iflammation, high collagen turnover or metabolic stress can out pace the body’s ability to make it.

People carrying excess weight or living with metabolic conditions like type 2 diabetes or fatty liver disease consistently show lower circulating glycine levels, which research suggests may be partly due to obesity itself slowing the body’s ability to make glycine from scratch. Chronic stress places additional demand on glycine, accelerating how quickly the body uses it up. And a high-protein diet, particularly one heavy in muscle meats, burns through glycine rapidly, because the liver needs it to process and eliminate excess methionine.

So really, glycine is “conditionally essential”, meaning that dietary intake is ofte n required to achieve optimal levels. However, a complete deficiency is unlikely in healthy individuals.

Glycine: The Master Builder

Glycine isn’t just “another amino acid.” It’s a structural backbone molecule.

It is required to make:

• Glutathione — often called the king of antioxidants. It helps the liver break down toxins, protects cells from oxidative stress and premature aging, and recycles other antioxidants like Vitamin C.

• Elastin — essential for skin elasticity

• Porphyrins — components of hemoglobin (oxygen transport) and cytochrome P450 (critical for liver detoxification)

• Creatine — crucial for muscle power and brain energy

• Other amino acids, proteins, and even DNA

It has a pretty important résumé for something considered “non-essential.”

Glycine also makes up about 25% of collagen. Without enough glycine and therefore collagen, you cannot effectively repair or maintain skin (hello, wrinkles), strengthen bone, cartilage, fascia, tendons, and ligaments, support muscle regeneration after exercise, or keep blood vessel walls strong and flexible.

If you care about aging well, inside and out, glycine matters.

Sleep, Brain, and Nervous System Balance

Glycine acts as an inhibitory neurotransmitter. It quiets the central nervous system, building resilience to stress and supporting mood, and it lowers core body temperature; a key biological signal that shifts the brain into deep, restorative sleep. It also helps balance excitatory signals in the brain, which may improve memory and cognitive performance.

Digestion and Fat Metabolism

Glycine facilitates bile acid conjugation, making bile water-soluble so it flows more freely. Proper, free-flowing bile is essential for digesting fat and absorbing the fat-soluble vitamins A, D, E, and K.

It also has protective effects on liver cells. With low glycine levels, the liver becomes inflamed, bile flow grows sluggish, fat begins to accumulate, and the liver’s detoxification pathways become inefficient.

Anti-Inflammatory and Cardiovascular Protection

Glycine reduces inflammation throughout the body, including in conditions like arthritis, chronic pain, and gum and tooth disease. It also acts as a natural blood thinner by preventing platelet aggregation.

These effects matter for the heart. Chronic low-grade inflammation at arterial branch points, where blood flow creates turbulence, is a known driver of atherosclerosis, contributing to heart attacks, strokes, and embolisms. Glycine may help interrupt that inflammatory cascade before it begins.

Hot Flashes

For women navigating perimenopause or menopause, glycine is worth knowing about. Taking 3–5 grams before bedtime may help reduce the frequency and intensity of hot flashes. This is likely because glycine lowers core body temperature and calms nervous system activity, the same mechanisms that support deeper sleep. The research here is still emerging, but given glycine's excellent safety profile, it's a low-risk option worth trying.

The Methionine Connection

Glycine is required to help the liver eliminate excess dietary methionine. It takes two glycine molecules to neutralize one methionine molecule. So if you eat a high-methionine diet, rich in animal protein, you will burn through glycine more quickly.

According to Dr. Joel Brind: we only need about 300 mg of methionine daily, because the body efficiently recycles it. For perspective, just two 50g eggs at breakfast contains about 180-210 mg of methionine. Most people eating a typical Western diet consume far more methionine than that… and pay for it in glycine.

The Modern Diet Problem

Modern diets emphasize high animal protein. Historically, humans consumed the whole animal — skin, cartilage, bone broth. Today we eat the steak and throw away the glycine-rich part and the result is a high methionine intake that creates a high demand for glycine.

How Much Glycine Do We Actually Need?

Your body uses roughly 60 grams of glycine per day across all its functions. It produces approximately 25–44 grams on its own, and a typical Western diet contributes another 2–4 grams, leaving a meaningful gap. Collagen formation alone requires 10–12 grams and then add on the demands from stress, inflammation, sleep regulation, and mood. This is why glycine is increasingly described as “conditionally essential”: technically producible, but practically insufficient for most people.

For most people, aiming for an additional 8–12 grams of glycine daily is a reasonable target. If you’re overweight, under significant stress, or dealing with poor sleep, chronic inflammation, allergies, arthritis or migraines, 15–20 grams may be more appropriate.

How to Get More Glycine into Your Diet

Gelatin Powder: Gelatin powder is about 33% glycine by weight, (roughly 1 gram of glycine per teaspoon of gelatin). As a bonus, it also contains proline and hydroxyproline, which are also essential for collagen synthesis. Look for pure gelatin with no additives. Dissolve it in warm water and stir into soups, stews, or sauces, or use it to make homemade jello or mousse.

Beef Bone Broth: One cup of homemade bone broth contains anywhere from 5–17 grams of glycine, depending on cooking time and what parts of the animal are used. Marrow-rich bones, knuckles, feet, tendons, skin, and joints are the richest sources.

To make it: rinse the bones and place them in a large pot, fully submerged in water. Add a splash of vinegar or lemon juice to help draw out the minerals and nutrients. Bring to a soft boil and skim off the foam, then reduce to simmer, cover, and leave for 8–12 hours. Once cooled, strain out the bones and store the broth in containers — it freezes well. A properly made broth will solidify into a gel when cold, which is your confirmation that the gelatin extracted successfully. I leave the fat layer on during storage to protect it, then remove it before reheating. Season with salt, pepper, or herbs to taste.

I drink 1–2 cups daily (during the cooler months).

The Bottom Line

When you get enough glycine, your body thrives on multiple levels. It builds and maintains collagen, keeping skin supple, joints flexible, and connective tissues strong. It supports your liver, digestive system, and detox pathways. It calms your nervous system and promotes deep, restorative sleep. In short, glycine is a quiet powerhouse supporting your body from the inside out, helping you stay strong, healthy, and resilient as you age.