Glycine
Glycine is the smallest amino acid and makes up about one in three of the amino acids in collagen. The body makes it from serine and uses it in nerves, glutathione, creatine and hemoglobin.
1 / 3 of collagenevery third amino acid in the chain is glycine
Not essential the body makes it from serine
Daily requirement · none set, because healthy adults make it
- Main sources Gelatin and collagen skin, bone broth, meat
- Side chain One hydrogen the smallest of all 20
- In the nervous system A calming signal in the spinal cord and brainstem
- In Caltide Not totaled yet no food data for it
No official daily amount or upper limit exists for glycine. Sources are listed at the end of this page.
Foods High in Glycine
Because collagen is so rich in glycine, the parts of an animal most people throw away hold the most.
- Gelatin and collagen powdersboth are collagen, so about one in three of their amino acids is glycine
- Skin, cartilage and bone brothchicken skin, pork rinds and broths simmered from bones and joints
- Meat and fishtougher cuts with more connective tissue have more than lean fillets
- Dairy, eggs, beans and grainssmaller amounts, as part of their protein
- Supplementsglycine powder, and the glycine bound into mineral glycinates
Caltide's food data does not list glycine yet, so foods are named without figures.
What Is Glycine?
Every amino acid has a side chain that sets it apart. Glycine's is a single hydrogen atom, the smallest possible, which makes it the only one of the 20 with no left- and right-handed forms. Its size is the reason for most of what it does.
Why Collagen Needs So Much Glycine
Collagen, the main protein of skin, tendons and bone, is made of three chains wound into a tight rope. The pattern repeats glycine, then two other amino acids, again and again, because only glycine is small enough to fit where the three chains press together at the center. Any other amino acid there weakens the rope, which is the cause of some inherited brittle bone disorders.
Glycine as a Nerve Signal
In the spinal cord and brainstem, glycine is a messenger that quiets nerve cells, which keeps muscle signals in check. The poison strychnine works by blocking glycine's receptors: without the brake, muscles go into violent spasms. Elsewhere in the brain glycine also helps activate NMDA receptors, which are involved in learning.
What the Body Makes From Glycine
Glycine joins glutamate and cysteine to form glutathione, the cell's main antioxidant. With arginine it starts the making of creatine. All four nitrogen atoms in heme, the ring that holds iron in hemoglobin, come from glycine. The liver also attaches glycine to bile acids before they are released to digest fat.
Glycinate on Mineral Supplement Labels
When a supplement says glycinate or bisglycinate, a mineral is bound to one or two glycine molecules. In magnesium glycinate, glycine is most of the weight, so a capsule holds far less magnesium than its total weight suggests.
The food library lists protein for every food; glycine figures are not in it yet.
Glycine Supplements
The body and food supply most glycine, but supplements are a source too, as a sweet white powder or in capsules.
What Studies Show About Glycine Supplements
The best-known use is sleep. A few small, short trials, mostly in Japan, gave 3 g of glycine before bed; people reported sleeping a little better and feeling less tired the next day. These were studied amounts in small groups, not an established dose, and no large trials have tested it.
Glycine Supplement Safety
- Side effectsusually mild, such as an upset stomach or loose stools
Ask a doctor or pharmacist before combining a supplement with a medicine. Not medical advice.
Tracking Glycine in Caltide
- Not totaled yetCaltide's food data does not include glycine, so Caltide does not add it up in the Nutrition tab yet. You can still list glycine as an ingredient when you add a supplement.
Glycine Sources and References
The figures and claims on this page are checked against these sources.
Questions About Glycine
It makes up about a third of collagen, calms nerve signals in the spinal cord and brainstem, and is a building block of glutathione, creatine and heme, the iron-holding part of hemoglobin.
No. The body makes it, mainly from serine, so no daily requirement is set. It is sometimes called conditionally essential because needs rise in fast growth and in preterm babies.
Foods made from skin, bone and connective tissue: gelatin, collagen powders, bone broth, pork rinds and chicken skin. Meat, fish, dairy and beans add smaller amounts.
Its taste is naturally sweet, and its name comes from the Greek glykys, sweet. It is approved in the EU as the flavor enhancer E 640.
The evidence is small. A few short trials, mostly in Japan, gave 3 g before bed and found people rated their sleep a little better and felt less tired the next day. No large trials have tested it.
A mineral bound to glycine, as in magnesium glycinate or iron bisglycinate. The glycine is part of the compound's weight, which is why a glycinate capsule holds less of the mineral than its total weight.
Not yet. Caltide's food data does not include glycine, so Caltide does not total it in the Nutrition tab.
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