Glycine Dosing: 5 Mistakes I Made (So You Don't Have To)

So there I was at 34, lying awake at 2 AM again, scrolling through PubMed abstracts about amino acids and sleep. I'd already tried magnesium threonate, melatonin, and a dozen other sleep hacks. Then I stumbled across glycine. A simple amino acid. Dirt cheap. Studies showing it improved sleep quality without the morning grogginess. I ordered 500 grams that night for like $18. What could go wrong?

Turns out, a lot. I spent the next 6 months making every possible mistake with glycine dosing. Took it at the wrong times. Used the wrong amounts. Mixed it with stuff that killed its effects. My sleep tracking data from that period looks like a drunk person drew it. But I learned. And now at 38, glycine is one of my non-negotiables. Here's everything I screwed up so you don't have to.

TL;DR - What I Wish I Knew About Glycine:

Disclaimer: I'm not a medical professional. This is just my personal experience after 4 years of experimenting with glycine. Always talk to your doctor before trying anything new, especially if you're on medications or have health conditions.

What Even Is Glycine and Why Did I Care?

Glycine is the simplest amino acid. Your body makes it, you eat it in protein (especially collagen), and it does a bunch of important stuff. It's a building block for collagen synthesis, helps make glutathione (your body's master antioxidant), and acts as an inhibitory neurotransmitter in your brain and spinal cord.

But here's what caught my attention: multiple studies showed that taking 3 grams of glycine before bed improved subjective sleep quality, reduced time to fall asleep, and increased slow-wave sleep without the side effects of sleep drugs. At 34, after 2 years of garbage sleep from my tech burnout, I was desperate.

There's also interesting research suggesting glycine might mimic some benefits of methionine restriction, which has been linked to longevity in animal studies. Basically, balancing your glycine-to-methionine ratio might be good for healthspan. That was a bonus. I just wanted to sleep.

Mistake #1: Starting With Way Too Little (1g)

My first order arrived, and like an idiot, I read the label on the bag instead of the actual research. It said "serving size: 1g." So that's what I took. Mixed 1 gram into water at 10 PM, drank it, waited for sleep magic.

Nothing. Absolutely nothing. For a week.

After reading like 50 papers on glycine (yes, I'm that person), I realized the effective dose in sleep studies was 3 grams. Some people respond to 2g, others need 5g. But 1g? That's basically nothing for sleep purposes.

What Actually Worked: I bumped up to 3 grams. Night one, I fell asleep maybe 10 minutes faster. By night three, my Oura ring showed a 22% increase in deep sleep compared to my baseline. My subjective sleep quality went from "okay I guess" to "actually refreshed in the morning."

The sweet spot for most people seems to be 3-5 grams before bed. I settled on 4g after testing different amounts for months. Your mileage may vary, but start at 3g minimum if you want sleep benefits.

Mistake #2: Taking It With My Protein Shake

Month two of my glycine experiment, I got lazy. I was already drinking a casein protein shake before bed (40g protein for overnight muscle recovery, or so I thought). Why not just dump the glycine in there? Efficient, right?

Wrong. My sleep quality immediately tanked back to baseline. Took me two weeks to figure out why.

Turns out, glycine competes with other amino acids for absorption and transport across the blood-brain barrier. When you take it with a big protein dose, you're flooding your system with all the other amino acids. The glycine has to fight for absorption. Most of it probably just got used for general protein synthesis instead of reaching the brain in sleep-promoting concentrations.

What Actually Worked: I started taking glycine on an empty stomach, at least 1-2 hours after my last protein-containing meal. Usually around 10 PM, about an hour before bed. Just glycine powder in 6-8 oz of water. Sleep quality came right back.

Some people mix it with a small amount of magnesium threonate for extra sleep support. That combo worked great for me and doesn't interfere with glycine absorption since magnesium isn't competing for the same transporters.

Mistake #3: Expecting Immediate Results (And Quitting Too Soon)

I'm embarrassed to admit this, but after my first failed week at 1g, I almost gave up entirely. "Just another overhyped supplement," I thought. Good thing I'm also stubborn and had already spent $18.

Even when I bumped to 3g, the first night wasn't life-changing. I noticed minor improvements, but nothing dramatic. Night two was about the same. I was skeptical.

But by night four and five? That's when it really kicked in. My sleep latency dropped from 25-30 minutes to under 15. Deep sleep consistently increased. I stopped waking up at 3 AM overthinking work stuff. Morning energy was noticeably better.

What Actually Worked: Give it at least 5-7 nights at the proper dose before judging. Glycine seems to have cumulative effects on sleep architecture. It's not a knockout drug like Ambien (thank god). It's more like your brain gradually remembers how to sleep properly again.

I tracked everything in a spreadsheet: dose, timing, Oura ring sleep scores, subjective morning ratings. The data was clear by day 7. Glycine worked, but it needed time.

Mistake #4: Buying Sketchy Glycine (Quality Actually Matters)

My first bag was from some random Amazon brand. $18 for 500g, seemed like a great deal. It dissolved okay, tasted vaguely sweet (glycine is named after the Greek word for sweet), and I assumed all glycine was the same.

Then I ran out and tried a different brand. This one had a weird chemical aftertaste. Like someone mixed glycine with pool cleaner. I pushed through for a week, but the taste was so bad I started dreading my nightly dose. Plus, my sleep improvements seemed to plateau.

I switched to a third brand from a company that did third-party testing and published certificates of analysis. Night and day difference. Clean taste, better dissolution, and my sleep metrics improved again.

What Actually Worked: I now only buy glycine from companies that provide:

Yes, it costs a bit more. Maybe $25-30 for 500g instead of $18. But 500g lasts me 4+ months at 4g per night. That's still less than $8/month for significantly better sleep. Cheaper than one bad night's sleep affecting my productivity.

Mistake #5: Not Timing It Right (Or Taking It In The Morning)

Around month three, I read that glycine might help with focus and cognitive function. So I started taking 3g in the morning with my coffee, thinking I'd get the best of both worlds. Sleep benefits at night, cognitive benefits during the day.

Bad idea. I felt slightly drowsy mid-morning. Not horribly tired, but definitely not sharp. Turns out glycine's inhibitory neurotransmitter effects don't care what time of day you take it. Taking sedating amino acids in the morning is not a recipe for productivity.

I also experimented with timing before bed. Too early (2-3 hours before sleep), and the effects seemed to wear off by the time I actually got in bed. Too late (right before bed), and I'd have to get up to pee 2 hours later, which killed my sleep continuity.

What Actually Worked: My optimal timing is 60-90 minutes before bed. So if I'm aiming for lights out at 11 PM, I take my 4g dose around 9:45-10:00 PM. Empty stomach, just water.

This gives it time to absorb and start working, but doesn't make me pee in the middle of the night (I limit the water to 6-8 oz). By the time I'm in bed, I feel that subtle relaxation that makes falling asleep easier.

For the focus benefits? I occasionally take 1-2g in the afternoon (around 2-3 PM) when I'm not worried about evening drowsiness. Some people use it to manage stress during the day. But I keep my main dose reserved for nighttime sleep support.

The Collagen and Longevity Bonuses I Didn't Expect

I started taking glycine purely for sleep. But after about 6 months, I noticed my nagging knee pain from running was way better. My skin looked slightly better (my girlfriend noticed before I did). And my hair and nails seemed to grow faster.

Turns out, glycine is about one-third of collagen's amino acid content. Your body needs a lot of it for collagen synthesis. Most people don't get enough from diet alone, especially if you're not eating bone broth, skin-on chicken, or pork rinds regularly (I wasn't).

There's also the methionine restriction angle. Methionine is an essential amino acid, but too much might accelerate aging through various mechanisms. Glycine may balance this out. Some researchers think the glycine-to-methionine ratio is more important than we realized for healthspan.

I'm not taking glycine specifically for longevity—I'm 38, not 68—but if it's helping my body make better collagen and potentially supporting healthier aging? I'll take it.

If you're interested in other compounds that support collagen and recovery, check out GHK-Cu, which I've used for skin health and wound healing with good results.

Other Forms of Glycine I Tried (Spoiler: Not Worth It)

Being obsessive, I also tried:

Glycine capsules: Way more expensive per gram. I'd need to swallow like 12 capsules for my 4g dose. Hard pass.

Ferrous glycine: This is an iron supplement where iron is chelated to glycine. I tried it when my ferritin was low (22 ng/mL at age 35). It worked fine for iron, but you're not getting therapeutic glycine doses from an iron supplement. Different purpose entirely.

Magnesium glycinate: Similar story. Great magnesium supplement, very gentle on the stomach. But the amount of glycine is minimal compared to sleep doses. I take mag glycinate separately for magnesium, not for glycine content.

Dimethyl glycine (DMG): This is a different compound entirely, sometimes called "glycin" in certain contexts. It's used for energy metabolism and immune support. I tried it for a month around age 36. Didn't notice much. Definitely not the same as regular glycine for sleep.

Copper glycine chelate: Another mineral chelate. Good for copper supplementation if you need it (most people don't). Not a glycine source.

Bottom line: Stick with pure glycine powder for sleep and collagen support. It's the cheapest, most effective form. All these chelated versions are for mineral supplementation, not glycine benefits.

My Current Glycine Protocol (4 Years Later)

I'm now 38. Here's what I do consistently:

Sleep support: 4g glycine powder in 6 oz water, taken at 9:45 PM, empty stomach. Every single night, no breaks. This is as non-negotiable as brushing my teeth.

Cost: About $7-8 per month buying quality 500g bags.

Tracking: I stopped obsessively tracking daily once I dialed it in, but I still check my Oura ring sleep scores weekly. My average deep sleep is now 1.5-2 hours per night (up from 45-60 minutes before glycine). Sleep efficiency is consistently 88-92%.

Bloodwork: I get comprehensive panels twice a year. Everything looks good. Glycine is extremely safe with virtually no side effects at these doses. My doctor isn't concerned.

Stacking: I combine it with 400mg magnesium threonate on nights when my stress is higher. Sometimes I'll add 200mg L-theanine if I had coffee too late. But glycine is the foundation.

I also experimented with NAD plus precursors for energy and longevity, but that's a separate stack.

Who Should (And Shouldn't) Try Glycine

Glycine might be worth trying if you:

Be cautious or skip it if you:

Seriously, talk to your doctor first. I'm not a medical professional. This is what worked for me.

Common Questions About Glycine (FAQ)

How long does it take for glycine to work for sleep?

In my experience, you'll notice subtle improvements within the first few nights, but the full effects take 5-7 days of consistent use. Glycine seems to have cumulative benefits on sleep architecture. Track your sleep quality for at least a week before deciding if it's working.

Can I take glycine every night long-term?

I've taken 4g every night for 4 years with zero issues. Glycine is a non-essential amino acid your body makes naturally, and you consume it in food. Studies haven't shown any safety concerns with long-term supplementation at 3-5g doses. That said, I'm not a doctor—discuss long-term use with yours.

Will glycine make me groggy in the morning?

Not in my experience. Unlike pharmaceutical sleep aids or even melatonin, I've never felt morning grogginess from glycine. It seems to improve sleep quality without the hangover effect. If you do feel groggy, you might be taking too much or combining it with other sedating supplements.

What's the difference between glycine and collagen supplements?

Collagen supplements contain glycine (about 33% by weight), but also other amino acids like proline and hydroxyproline. If you're taking collagen for joint or skin health, you're getting some glycine. But for sleep benefits, you'd need about 12-15g of collagen to get 4g of glycine, and the other amino acids might interfere with absorption. For sleep, pure glycine is more effective and cost-efficient.

Final Thoughts: Was It Worth The Trial And Error?

Absolutely. I wasted 6 months figuring out the right dose, timing, and quality. I probably spent an extra $50-75 on brands that didn't work. But now? Glycine is one of my highest-ROI supplements.

$8 per month for consistently better sleep, faster recovery from workouts, and potential longevity benefits? That's a no-brainer. My sleep quality at 38 is better than it was at 28, and glycine is a huge part of that.

If you're struggling with sleep and haven't tried glycine yet, start with 3 grams before bed for a week. Empty stomach, quality source, proper timing. Give it the full 7 days. Track your sleep somehow—even just subjective notes in your phone.

And for the love of god, don't make my mistakes. Don't start at 1g. Don't take it with protein. Don't buy the cheapest sketchy powder on Amazon. Learn from my expensive trial and error.

Your future well-rested self will thank you.