Glycine for Sleep at 71: Why I Take 9 Grams Every Night

Every night before bed, I take 9 grams of glycine. That is three times the 3 grams most sleep studies use, so this post covers why I take it, what the research actually shows, and where the evidence runs out.

What Glycine Is

Glycine is the simplest amino acid your body makes. The name comes from the Greek word for sweet, and the powder does taste lightly sweet.

It does a lot of jobs. It is a big part of collagen. It works as a calming signal in the brain and spinal cord. And it is one of the three building blocks your body uses to make glutathione, its main internal antioxidant.

Your body makes glycine on its own, but there is good reason to think older adults do not make enough of it for everything it is needed for.

Why I Take It

I take glycine for two reasons: sleep, and glutathione.

Sleep is where everything else in my protocol either works or does not. I track my sleep score and my brain waste clearance number every morning, so anything that might help me fall asleep faster and sleep deeper is worth testing. My whole nightly routine is in how I mastered sleep at 71.

Glutathione is the second reason. It tends to fall with age, and glycine is one of the raw materials needed to make it. Rather than taking glutathione itself, I give my body one of the raw materials it needs to make its own.

What the Research Actually Shows

Sleep. In a small Japanese study, people who took 3 grams of glycine before bed reported better sleep, fell asleep faster and reached deep sleep sooner than on placebo, and sleep lab recordings backed that up. It is a small study, but the result has been repeated in other small trials.

Body temperature. Your core temperature has to drop for you to fall asleep. In a 2015 study in rats, glycine worked through a part of the brain that runs the body clock, sending blood to the feet so the body could shed heat. Core temperature dropped, and the animals fell asleep. That mechanism is well worked out, but it is animal work.

Glutathione and aging. This is the part that caught my attention. In a 2023 randomized trial at Baylor College of Medicine, older adults aged 61 to 80, took glycine and N-acetylcysteine together (called GlyNAC) for 16 weeks. The dose was 100 mg of each per kilogram of body weight, which is roughly 8 grams of glycine a day for a 180-pound man. Compared with placebo, they corrected their glutathione deficiency and improved on oxidative stress, inflammation, insulin resistance and physical function. It was only 24 older adults, and it tested glycine combined with NAC, not glycine alone.

Lifespan. The National Institute on Aging’s Interventions Testing Program found that glycine in the diet extended lifespan in both male and female mice. The effect was small, a few percent, but it held up in a program that is known for being hard to pass.

Where the evidence is thin: there is no good study of 9 grams a night for sleep in healthy older adults. The sleep trials used 3 grams. My dose is close to what the GlyNAC trial used, but that trial paired it with NAC, so I am making a judgment call, not following a proven protocol.

My Dose and Timing

Dose: 9 grams of glycine powder
When: every night, before bed
Form: powder, which is much cheaper than capsules at this dose

At 9 grams a night, a one-pound bag lasts about seven weeks. The powder I use is Nutricost Glycine Powder. That is an Amazon affiliate link, and I earn a small commission if you buy through it, at no extra cost to you.

My glycine sits alongside the rest of my evening routine, including L-theanine, which is all on my protocols page.

What I Am Watching

My sleep score and brain waste clearance go into my health app every morning, next to my blood pressure. That is how I will judge this, not by how I feel. If the numbers do not move, I will say so.

Would I Tell Someone Else to Take It?

If you want to try glycine for sleep, the research points to 3 grams before bed, not 9. Start there.

Glycine has a good safety record, and much higher doses have been used in studies. But large doses can upset your stomach. And if you take clozapine, talk to your doctor first. In one trial, 30 grams a day of glycine added to clozapine seemed to make the drug work worse.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This is one of the things on my full supplement stack, where every item is listed with its dose.

If you want the rest of what I do, my full daily regimen is in my protocols, the training side is under fitness, every number I track is in test and stats, and the products I actually use are on my discount codes page. New here? Start with my 200 Year Life protocol.

I share what I am testing, and how the numbers turn out, on my YouTube channel. Subscribe there to follow along.

Live long and prosper,

Gary

A note from Gary: I am not a doctor, and I am definitely not your doctor. I am a 71-year-old running a 129-year experiment on myself and publishing the results as they come. Glycine can affect sleep and interact with some medications. Talk to your physician before changing anything about your own health.