4 Best Glycine Supplements in 2024

If you’re struggling with sleep, you may be looking for supplements to help. While there’s no substitute for proper sleep hygiene, a supplement like Glycine may make a difference in your ability to get a good night’s rest. Research has shown that glycine not only improves sleep quality, but decreases fatigue as well.

Top 4 Best Glycine Supplements Reviewed

1. Nutricost Glycine – Top Pick
2. Carlson Glycine Powder – Runner-Up
3. NOW Foods Glycine
4. Thorne Glycine

Product	Total	Servings per Package	Convenience of use	Label Transparency	Price/ Quality
Nutricost	40	10	10	10	10
Carlson	37.5	9	10	9.5	9
NOW Foods	37.5	9	9.5	10	9
Thorne	36.5	9.5	9	9.5	8.5

1. Nutricost Glycine – Top Pick

• Form: Powder
• Suitable for Vegans: Yes
• Servings per Package: 151
• Price per Serving: ~$0.17
• Company Founded: 2012
• Recommended by Athletes: Paul Maile, Max Tooley, Amari Whiting

Starting off our list and our top pick for the best glycine powder comes from Nutricost. Let’s see why this earned a spot at the top of our list!

First, this is one of only 2 supplements on our list to be dosed at 3g per serving. This is important as it’s a dose that has been shown in studies to produce positive effects on sleep when compared to a placebo. With that being said, it’s difficult to say how much glycine will be beneficial on an individual basis.

While the powder form may be less convenient for some, mixing one scoop with a glass of water will likely be more ideal than taking several pills everyday.

This product is also made in a GMP compliant facility, as well as being third-party tested for quality! Like all of Nutricost’s products, it also comes with a quality guarantee.

Finally, Nutricost lives up to its name by offering the best value for money on our list. Each 3g serving will only cost you about $0.17!

2. Carlson Glycine Powder – Runner-Up

• Form: Powder
• Suitable for Vegans: Yes
• Servings per Package: ~33
• Price per Serving: ~$0.32
• Company Founded: 1965
• Recommended by Athletes: Ashley Kulbeck, Elise Brisco, Arin Wright

Next up on our list is the last glycine powder we’ll be covering from Carlson Nutritional Supplements. Let’s see how this stacks up against the top spot on our list.

The main difference here is the dosage. Carlson is dosed at only 2g per serving, which is slightly less than the 3g dose used in the study we’ll be covering below. While 2g is recommended to be supplied with diet, you may need to take slightly more than this to get an effective dose for improving sleep quality.

Similar to Nutricost, Carlson has a guarantee for both potency and quality, as well as ensuring their product is manufactured in an FDA regulated facility.

It’s worth noting that despite being fairly cheap, this is still a significantly more expensive option than Nutricost. Assuming a standard 3g serving, each serving will cost you about $0.32.

3. NOW Foods Glycine

• Form: Capsules
• Suitable for Vegans: Yes
• Servings per Package: 33
• Price per Serving: ~$0.31
• Company Founded: 1968
• Recommended by Athletes: Dan McDonogh, Bianca Summer Macedo, Danielle Colaprico

Next on our list is the first capsule-based glycine supplement we’ll be reviewing from NOW foods. If you’re not a fan of powder-based supplements, then this may be the choice for you!

Like Nutricost, NOW Foods’ product is dosed at 3g per serving, which should be a solid dose as we’ve covered above. Just keep in mind that this is split over 3 capsules, so you will be taking a decent amount of pills everyday to get your glycine in. 

As with the products above, NOW comes with a quality assurance. The product is GMP quality assured as well as being UL certified. Also, it’s worth noting that NOW is partnered with Vitamin Angels, a charity devoted to providing healthcare to underserved communities. 

Keep in mind that capsules are typically more expensive than powders, although this is still a very cheap option. Each serving of NOW’s glycine will only cost you about $0.31.

4. Thorne Glycine

• Form: Capsules
• Suitable for Vegans: Yes
• Servings per Package: ~42
• Price per Serving: ~$0.63
• Company Founded: 1984
• Recommended by Athletes: Jess Stay Fit, The Well Pursuit, Isaiah Washington

Closing off our list is Thorne’s Glycine capsules. While these are the most expensive choice on our list by far, they are still effective as long as they’re dosed appropriately.

Thorne’s recommended dosage is 1g, which is split over 2 capsules. This means you’d need to be taking 6 total capsules to get a 3g dose of glycine. While a lower dose may be suitable, it will be fairly inconvenient for most to get 3g, especially if they’re taking it all at once.

It’s also worth noting that Thorne is the first brand on our list to not feature any third-party quality assurance. So, if this is important to you, we recommend the other 3 products on our list instead.

Finally, this is the most expensive supplement we’ve covered by far at ~$0.63 for an effective dose. Considering the ineffective dosing and lack of quality assurance, it’s difficult to strongly recommend Thorne’s product.

What Is Glycine?

Glycine is a nonessential amino acid, as it is synthesized through the body. This means it does not need to be included in the diet for the body to get sufficient glycine. However, glycine concentrations are high in most protein sources, so if you’re eating a high-protein diet, you’re likely getting plenty of additional glycine in as well.

Like most amino acids, Glycine has several roles in the body, mainly related to metabolic regulation, anti-oxidative reactions, neurological function, and more. Because of its role in the CNS, it appears glycine has a potentially beneficial role on sleep quality.

Studies show that 3g dose of glycine before bed appears to subjectively improve qualities of fatigue and clear-headedness after waking. Individual results may vary, so consider experimenting with dosages to see what produces the best results for you. Supplemental glycine in moderate doses is largely used as a sleep aid. As we’ll be covering below, this may be its main benefit for athletes.

How Can Glycine Be Useful for Athletes?

1. May Improve Sleep Quality

First, one of the main reasons glycine appears to be beneficial in promoting sleep is that it has hypothermic effects. Essentially, glycine reduces core body temperature, which in turn leads to better sleep quality. This is because the body needs to lower its core temperature by 2-3 degrees to fall asleep – a process which appears to be supported by glycine supplementation.

This is especially relevant to athletes who need to maximize their sleep quality in order to perform at their best. As we’ll be covering below, studies on humans have shown glycine to reduce symptoms of fatigue, which is an indicator of improved sleep quality.

2. May Decrease Morning Fatigue

There are 2 studies which showed glycine to be beneficial for sleep.

The first study had people sleep less than usual, and found that glycine supplementation reduced subjective feelings of sleepiness and fatigue induced by the sleep restriction.

Ultimately, just because glycine led to subjective improvements in alertness, no supplement can make up for a genuine lack of sleep. As a result, we strongly advise against using glycine as an excuse to get less sleep. Sleep deprivation can result in serious health problems!

A similar study also examined glycine’s effect on fatigue, although sleep was not purposely restricted alongside supplementation. This study also found reduced symptoms of fatigue, and noted that subjects felt better upon waking.

Both of these studies used 3g of glycine to produce these effects, indicating that this is an effective dose for improving sleep quality, and decreasing fatigue as a result. It’s worth noting that individual results may vary, so feel free to experiment with lower or higher doses to see what works best for you!

These findings may be especially relevant to athletes who need to train or compete first thing in the morning. If glycine is able to reduce symptoms of fatigue upon waiting, you may be able to perform at a higher level shortly after waking with glycine supplementation. Just make sure you understand the reasons of that morning fatigue.

How to Take Glycine for Better Sleep?

As mentioned, studies show that 3g of glycine taken before bed promotes better sleep quality and decreased fatigue the next day. As a result, this is what we determined as a solid starting dose for improving sleep. Feel free to experiment with different doses to see what works best for you!

It needs to be noted that glycine is not a miracle solution for improving sleep quality. While it does appear to be effective in helping with sleep, be sure you’re practicing proper sleep hygiene as well.

We don’t recommend relying on a supplement for sleep if you struggle with poor sleep quality. Instead, start by making lifestyle changes like reducing light before bed, or lowering the temperature in your room. This will help you make more sustainable and long-lasting changes to your sleep-quality.

While glycine may be beneficial, it’s important to treat it as a tool for improving sleep quality instead of something that’s necessary for you to get a good night’s sleep.

FAQ

Is It Safe to Take Glycine Every Day?

Yes, there doesn’t appear to be any issue with taking glycine everyday, especially in moderate doses of around 3g. There may be some mild side effects including an upset stomach. If you’re concerned about any potential side effects, consult with a doctor before using glycine.

Which Is Better, Gaba or Glycine?

Orally ingested GABA does not appear to be as effective as glycine for improving sleep quality. While GABA has been recommended as a treatment for anxiety and insomnia, these claims don’t appear to be backed up by anything. As a result, if you’re debating between the 2, we recommend sticking with Glycine for this purpose instead.

Who Should Not Take Glycine?

Pregnant and breastfeeding women, children, and anybody with pre-existing liver or kidney conditions should exercise caution before taking glycine. Really, anybody with pre-existing health conditions should consult with a doctor before taking glycine – or any supplement – to make sure it’s safe for them.

Conclusion

Overall, glycine does appear to be an effective supplement for improving sleep quality and reducing fatigue. While it’s certainly not a miracle cure for insomnia, it does appear to have genuine benefits for improving sleep quality. Just be sure you’re taking it at an effective dose for you, which will likely be somewhere around 3g/day.

We hope these glycine supplement reviews are able to help you find a supplement that’s right for you! If you’re looking for a high-quality glycine powder, we recommend Nutricost Glycine. If you’re more interested in a capsule-based supplement, consider using NOW Foods Glycine instead!

Have you ever tried glycine for improving sleep quality? Any other tips for getting a better night’s sleep? Let us know in the comments below!

Also read:

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• What Supplement Helps Reduce Lactic Acid
• Best N-Acetylcysteine Supplement
• Best Supplements for Bodybuilders
• Best Hmb Supplement
• Best Zma Supplement
• Best Glucosamine Chondroitin

References:

1. Molecule of the Week Archive, “Glycine,” American Chemical Society, https://www.acs.org/molecule-of-the-week/archive/g/glycine.html (accessed October 17, 2023)
2. Nobuhiro Kawai, et. al “The Sleep-Promoting and Hypothermic Effects of Glycine are Mediated by NMDA Receptors in the Suprachiasmatic Nucleus” Neuropsychopharmacology. 2015 May; 40(6): 1405–1416.
3. Makoto Banna, et. cal “The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers.” Front Neurol. 2012 Apr 18;3:61
4. Kentaro Inagawa, et al. “Subjective effects of glycine ingestion before bedtime on sleep quality.” Sleep Biol. Rhythms 4. 2006. P75–77.
5. Piril Hepsomani, et. al, “Effects of Oral Gamma-Aminobutyric Acid (GABA) Administration on Stress and Sleep in Humans: A Systematic Review,” Front. Neurosci., 17 September 2020