4 Best Glycine Supplements in 2023

Author: Jacek Szymanowski (M.Sc.Eng. Biotechnology, Sports Nutritionist)

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.

 In a hurry? 

In a hurry?

In a hurry and can’t keep reading? How about you check out the Nutricost Glycine.

Our top choice for the best glycine powder is Nutricost, primarily due to its 3g per serving dose, which has been demonstrated in studies to improve sleep compared to a placebo, even though individual benefits may vary.

Best Glycine Supplement

Top 4 Best Glycine Supplements Reviewed

per Package
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NOW Foods37.599.5109

1. Nutricost Glycine – Top Pick

Nutricost Glycine

  • 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!

40Expert Score

Nutricost Glycine, a powdered supplement, offers a more convenient option than daily pills, made in a GMP compliant facility, third-party tested for quality, and backed by Nutricost's quality guarantee, all at a great value.

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  • Best value for money

  • Dosed at 3g, which has produced positive results in certain studies

  • Tested for quality

Could be better:

  • Some people may prefer pills over capsule

  • Limited amount of reviews available

2. Carlson Glycine Powder – Runner-Up

Carlson Glycine Powder

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.

37.5Expert Score

Carlson Glycine Powder, with a slightly lower dosage than our referenced study, offers quality assurance and FDA-regulated production, albeit at a somewhat higher price point compared to Nutricost.

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  • Comes with a quality assurance

  • Made in an FDA regulated facility

  • Will provide proper effects given an effective dose

Could be better:

  • 2g dose may be too low for some

  • Most expensive powder on our list

NOW Foods Glycine

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.

37.5Expert Score

NOW Foods Glycine offers a 3g per serving dosage, split across three capsules, providing a cost-effective choice with quality assurance, GMP and UL certification, and a charitable partnership with Vitamin Angels.

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  • Best budget-friendly capsule-based option

  • Comes with multiple quality assurances

  • NOW is partnered with healthcare charity, Vitamin Angels

Could be better:

  • Capsules will be slightly more expensive than powder

  • 3 capsule servings may not be convenient for everyone

Thorne Glycine

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.

36.5Expert Score

Concluding our list, Thorne Glycine capsules are the costliest choice, requiring a specific dosing approach and lacking third-party quality assurance, making them a less favorable option compared to others.

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  • Small capsules may be easier to take

  • Small serving size makes it easy to split into multiple doses

  • Plenty of positive reviews

Could be better:

  • Most expensive product on our list

  • Recommended dose may be too low for some

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.

Athlete Drinking Glycine

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.

Man Weightlifting Training

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.

Man Drinking Glycine Supplement

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.

Female Deadlifting Workout


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.


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!


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

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Nutricost Glycine

Jacek Szymanowski

M.Sc.Eng. Biotechnology,
Sports Nutritionist

Experience: 20 years

With my 30 years fighting experience, specialization in nutrition coaching for athletes, expertise in metabolic health and dietary strategies, I bring a comprehensive approach to optimizing your performance and well-being. Backed by a master's of science degree in biotechnology, I stay at the forefront of scientific advancements, ensuring that my coaching is always evidence-based and up-to-date.

If you have any questions/suggestions/any other inquiry, you can reach out to us via email - reviews@torokhtiy.com

This article was written by our qualified author and proofread by an expert with proven experience. When writing the article we've used our expertise and data from authoritative, scientific, and evidence-based sources. The list of references is provided at the end of the article.

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