Glycine for Sleep and Skin: What it Actually Does

Patients ask me two things more than almost anything else. How can I sleep better? And why does my skin look tired even when I feel fine? I used to answer these separately. Then I started paying closer attention to one amino acid that shows up in both conversations: glycine.

What glycine actually does

Glycine is the smallest amino acid in the body. It's also one of the most abundant. Roughly a third of the amino acids that make up collagen are glycine, which makes it a core building block for skin, tendons, and bone.⁴ Glycine also works as a calming neurotransmitter in the brain and nervous system. That dual role, structural and neurological, is what makes it worth paying attention to.

How glycine may help you fall asleep

Glycine appears to lower your core body temperature slightly before bed, which may help signal to your body that it's time to rest.¹ In one clinical study, adults who took glycine before bedtime reported meaningfully better sleep quality the next morning.² Research also suggests glycine can raise serotonin levels in the brain without raising dopamine, which may help support a more regular sleep-wake rhythm.³

None of this works like a sedative. It's closer to removing friction from a process your body already knows how to do.

Why glycine matters for your skin

Collagen gives skin its structure. As we age, natural collagen production slows, and skin gradually loses some of the firmness it once had. Because glycine makes up such a large share of collagen's amino acid structure, it's one of the raw materials your body needs to keep producing it.⁴

A recent clinical trial tested a blend built mostly around glycine, paired with two other amino acids naturally found in collagen. Participants who took it saw visible improvements in skin appearance within just a few months.⁵ That's not a guarantee for every formula or every person. But it's a strong signal that the raw materials matter.

How much glycine do you actually need?

Most sleep research uses around three grams of glycine taken before bed.² You can get glycine from food, especially bone broth, gelatin, and collagen-rich cuts of meat, but most people don't eat those regularly enough to reach that amount through diet alone. That's the appeal of a consistent, measured dose every day, rather than trying to remember which foods contain it and how much.

The overnight connection

Here's what I find most interesting as a dermatologist. Deep sleep is when your body does most of its repair work, including collagen synthesis. Glycine shows up in both processes: helping you get to that deep sleep, and supplying material your body uses once you're there.

This is the idea behind Continuum's approach. What happens at the cellular level while you sleep shows up on your skin the next day. Skin-deep is cell-deep.

Why I included glycine in Intelligent Age Delay

When I formulated Intelligent Age Delay, I built it around four ingredients I trust most for cellular-level aging support: NAC, NMN, glycine, and quercetin. Glycine earned its place for the reasons above. It supports the systems working while you sleep, and the structure you see when you wake up.

Intelligent Age Delay is six capsules a day, three in the morning and three at night. That rhythm matters more than any single ingredient. Consistency is the compound.

References

1. Sleep Foundation. "Glycine for Sleep: Benefits, Dosage, and Side Effects."
2. Kawai N, et al. "New Therapeutic Strategy for Amino Acid Medicine: Glycine Improves the Quality of Sleep." Journal of Pharmacological Sciences (via ScienceDirect).
3. Sleep Doctor. "Glycine for Sleep: Benefits, Side Effects, and Dosage."
4. "Research Progress on Bioactive Factors against Skin Aging." PMC, National Library of Medicine.
5. "A collagen amino acid composition supplementation reduces biological age in humans and increases health and lifespan in vivo." NPJ Aging (Nature).