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Glycine

Amino Acid Evidence: limited

Overview

Glycine is the simplest amino acid and a conditionally essential nutrient. It is a major structural component of collagen (~33% by mass) and functions as an inhibitory neurotransmitter and NMDA receptor co-agonist. Research has investigated glycine supplementation for sleep quality, exercise recovery, and creatine synthesis. Safety is excellent with no established upper limit. Typical studied doses are 3–5 g/day.

Dosage

3000 mg · Evening · Can take on empty stomach

Key Interactions

19 verified interactions found

Melatonin Caution

Melatonin prevents glycine-induced reductions in mitochondrial complex IV activity and antioxidant depletion.

Melatonin kann den Stoffwechsel von Glycin in Körperzellen beeinflussen; die klinische Bedeutung beim Menschen ist bislang unklar. Eine gleichzeitige Einnahme ist auf Basis der vorliegenden Daten unbedenklich.

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Threonine Caution

Threonine supplementation increases spinal cord glycine levels, potentially treating muscle spasticity.

Threonin kann Glycin-Spiegel erhöhen; kombinierte Einnahme beeinflusst den Glycin-Stoffwechsel. Kombination in Standarddosen ist unkritisch.

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Quercetin Caution

Quercetin, a plant flavonoid, blocks the activity of both glycine and serotonin receptors, which can affect neurotransmission and cellular signaling.

Quercetin kann Glycin-Rezeptorkanäle hemmen, was vorwiegend in Zellmodellen gezeigt wurde. Bei gleichzeitiger Einnahme hoher Dosen ist Vorsicht geboten; die klinische Relevanz beim Menschen ist nicht abschließend geklärt.

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Proline Caution

Glycine blocks proline uptake, preventing embryonic stem cell differentiation in response to growth signals.

Glycin kann die zelluläre Prolin-Aufnahme hemmen. Bei gleichzeitiger Supplementierung beider Aminosäuren zeitversetzt einnehmen (mindestens 2h Abstand).

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Arginine and glycine together increase creatine production inside cells for muscle and brain energy.

Glycin ist ein direktes Substrat für die Kreatin-Biosynthese; kombinierte Einnahme kann die körpereigene Kreatin-Produktion unterstützen. Kombination in Standarddosen ist unkritisch.

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What Experts Say

“I will take two grams of glycine and a hundred milligrams of GABA in addition to the standard sleep stack... which I find greatly enhances my ability to get into sleep”
Andrew Huberman · Sleep Toolkit: Tools for Optimizing Sleep & Sleep-Wake Timing · Watch clip

Huberman takes 2 g glycine (with GABA) on nights when he needs extra sleep onset support, stacking it on top of his core sleep stack. He reports it greatly enhances his ability to fall asleep and reserves it for specific nights rather than daily use.

Scientific Sources

Frequently Asked Questions

What is Glycine used for?

Glycine is the simplest amino acid and a conditionally essential nutrient.

What is the recommended dosage for Glycine?

3000 mg. Evening. Can take on empty stomach.

Does Glycine interact with other supplements?

Glycine has 19 verified interactions. Top: Melatonin, Threonine.

When is the best time to take Glycine?

Evening. Can take on empty stomach.

Is Glycine safe to combine with other supplements?

Always check interactions before combining supplements. Use VitalStack to verify your full stack for free.

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Not medical advice. VitalStack is not a medical device. For personalized health recommendations, consult a healthcare provider.