Health Guide

Glycine

Glycine is the simplest amino acid, yet it holds powerful sway over your sleep, metabolism, and joint health. Often called a 'conditionally essential' amino acid, your body makes it, but you also get it from food—especially protein-rich sources like bone broth and meat. Why does it matter? Glycine acts as a calming neurotransmitter in your brain and helps build the collagen that keeps your skin firm and joints flexible. Think of it as your body's 'repair and relax' molecule. While it’s a simple chemical (NH2CH2COOH), its effects on deep sleep and inflammation are profound. This guide covers how to get it naturally and whether a supplement is right for you.

Evidence BasedDietary Supplement

VERIFIED SOURCE

Bio-Activity Analysis

Glycine Content in Bone Broth vs. Muscle Meat

SCIENTIFIC DATA VISUALIZATION

Y-Axis

Glycine mg/100g

Source →

Health Benefits & Sources

Why You Need It

Deep, Restorative Sleep: Glycine lowers core body temperature and calms the brain, helping you fall asleep faster and improving sleep quality.
Joint & Skin Health: It is a primary building block of collagen, the protein responsible for skin elasticity and cartilage repair.
Cognitive Boost: It acts as a neurotransmitter that may improve memory and protect the brain from oxidative stress.
Blood Sugar Regulation: Emerging research suggests it helps improve insulin sensitivity.

Deep Dive

Glycine is unique because it serves two distinct roles: it is a structural component of proteins and a signaling molecule in your central nervous system. Structurally, about one-third of collagen is made of glycine. Without it, your body struggles to repair tissue damaged by injury or aging.

As a neurotransmitter, glycine inhibits the 'fight or flight' response and promotes the 'rest and digest' state. This is why taking it before bed can significantly improve insomnia symptoms without the grogginess of pharmaceutical sedatives. It is also essential for producing creatine and nucleic acids (DNA/RNA).

Natural Food Sources

The best way to consume glycine is through whole foods, particularly those rich in connective tissue. Bone broth is the superfood of glycine, offering a highly bioavailable form.

Food	Amount (approx. per 100g)	% Daily Value (DV)
Chicken Skin	3.1g	~400%
Pork Skin	2.8g	~350%
Beef Gelatin	2.5g	~300%
Bone Broth	1.5g	~200%
Turkey Dark Meat	1.2g	~150%

Supplementation

If you do not consume much meat or collagen, collagen peptides are an excellent supplement that naturally contains high amounts of glycine.

Pure Glycine Powder: Usually taken in doses of 3g to 5g (approx. 1 teaspoon) before bed for sleep support, or up to 10g daily for metabolic health.
Usage: It has a slightly sweet taste and dissolves easily in water or tea.

Top Food Sources

Bone Broth

The #1 natural source

Pork/Chicken Skin

Eat the skin for the glycine

Beef Gelatin

Great for mixing into drinks

Sesame Seeds

Best plant-based source

Turkey/Dark Meat

Higher than white meat

Frequently Asked Questions

Not exactly. Gelatin is a mixture of proteins derived from collagen, and glycine makes up about one-third of that protein. So, gelatin is a rich source of glycine, but glycine is the pure amino acid.

Yes, absolutely. Vitamin C is essential for your body to synthesize collagen using glycine. They work synergistically for skin and joint health.

No. Glycine is very low in calories (4 calories per gram). While it supports metabolism, it does not cause weight gain.

Yes. Because your body uses it up quickly for repair and it is a natural component of protein, daily use is considered safe and effective for long-term sleep support.

Safety & Side Effects

Safety: Glycine is generally recognized as safe (GRAS) by the FDA. It is a natural component of your diet.
Side Effects: Very rare. High doses (above 15g at once) may cause mild stomach upset or soft stools.
Interactions: None known.
Caution: There is theoretical concern that high doses could affect those with rare conditions involving glycine metabolism (like nonketotic hyperglycinemia), but this is primarily relevant to infants.
Chemical Safety: It is a non-toxic, sweet-tasting white powder. It is considered very safe for daily use.

Scientific References

[1]Bannai, M., & Kawai, N. (2012). 'Glycine and sleep.' *Neuroscience & Biobehavioral Reviews*.
[2]Yamadera, W., et al. (2007). 'Glycine ingestion improves subjective sleep quality.' *Sleep and Biological Rhythms*.
[3]Liu, Y., et al. (2019). 'Glycine metabolism and its role in cancer.' *Cell Metabolism*.