Evidence report · Sleep

Glycine

Glycine before bed is a common, well-tolerated sleep aid with a fairly consistent body of studies, though not drug-grade trials. It is also a building block of collagen and glutathione. Side effects are rare at normal doses.

Verdict

Leaning for

Glycine is worth taking.

6 sources: 3 positive, 3 partly

6 sources: 3 positive, 3 partly

6 sources credited8 counted mentions19 episodes · 28 h8 checked quotesChecked against the tape 2026-03-23

Does it work?

Each claim gets one verdict, worked out from every counted mention. One dot is one source: a researcher or a study. Tap a dot to see its receipt.

positive partly neutral negative Each researcher and each study counts once per claim, however often they come up.

  1. Leaning for

    Glycine is worth taking.

    6 sources: 3 positive, 3 partly.

    Researchers say

    3 positive, 3 partly

    Studies show

    No study counted yet.

    21 more not counted · see why
    We could not tell what position it takes on this claim. 11
    The study cited could not be identified. 3
    We could not confirm who is speaking. 2
    No quote from the tape on record yet. 2
    Part of a sponsor's ad. 1
    A host's remark inside an interview. 1
    We could not tell where the evidence comes from. 1
    Show the receipts from 6 sources

    1. Mark Hyman, on The Dr. Hyman Show, at 19:58 Video · positive · Opinion

      “it's an amino acid and it can really help support sleep quality.”

    2. Dr. Peter Attia, on FoundMyFitness, at 3:45:35 Video · positive · Opinion

      “there's certain supplements that I use to sleep as well also I'm a fan of glycine”

    3. Dr. Craig Koniver, on Huberman Lab, at 1:31:56 Video · positive · Opinion

      “we all need to do some sort of you know liver mitigation strategies glycine is one of the best”

    4. Dr Michael Breus, on Rangan Chatterjee's channel, at 1:28:37 Video · partly · Opinion

      “Also, the glycine is helps with temperature regulation.”

    5. Luc van Loon Video · partly · 2 mentions

      on The Drive, at 2:30:37 · partly · Opinion

      “a protein supplement that also has a little bit of collagen in order to be sure that I get enough Glycine and Proline”

      on FoundMyFitness, at 2:04:17 · partly · Opinion

      “maybe in those conditions you need sources of extra Glycine and protein”

    6. Andrew Huberman, on Huberman Lab, at 1:18:07 Video · partly · Opinion

      “So I'm taking mag threonate, apigenin, and theanine, and then I will also take two grams of glycine and GABA, which I find greatly enhances my ability to get into sleep.”

  2. Leaning for

    Glycine before bed improves sleep quality.

    4 sources: 2 positive, 2 partly.

    Researchers say

    2 positive, 2 partly

    Studies show

    No study counted yet.

    5 more not counted · see why
    The study cited could not be identified. 2
    Part of a sponsor's ad. 1
    We could not tell where the evidence comes from. 1
    No quote from the tape on record yet. 1
    Show the receipts from 4 sources

    1. Mark Hyman, on The Dr. Hyman Show, at 19:58 Video · positive · Opinion

      “it's an amino acid and it can really help support sleep quality. Can help lower your core body temperature, promotes deeper sleep,”

    2. Dr. Craig Koniver, on Huberman Lab, at 1:31:29 Video · positive · Opinion

      “kind of TS down the nervous system people relax a little bit and then they tend to sleep better from it”

    3. Dr Michael Breus, on Rangan Chatterjee's channel, at 1:28:37 Video · partly · Opinion

      “the glycine is helps with temperature regulation.”

    4. Andrew Huberman, on Huberman Lab, at 1:18:07 Video · partly · Opinion

      “So I'm taking mag threonate, apigenin, and theanine, and then I will also take two grams of glycine and GABA, which I find greatly enhances my ability to get into sleep.”

5 more claims on dose, form and timing, each with its verdict and receipts, are in the full report.

How much, which type, and when?

Free with an account ↓
Dose
Form
Timing
Evidence
Verdict
Leaning for · 6 sources: 3 positive, 3 partly

Is it safe for me?

6 risks to check before you start

  1. Glycine is very well tolerated. At usual supplement doses (1-5g), side effects are rare.
  2. Very high doses (above 10g) may cause mild stomach upset, nausea or soft stools in some people. Start with 1-2g and build up.
  3. Glycine may lower blood pressure, so people on blood pressure drugs should monitor it and ask their doctor.
  4. Some low-quality whey brands add glycine for 'nitrogen spiking' to inflate the protein count on the label. That is a buying risk, not a glycine risk (Layne Norton, on The Drive).
  5. People on clozapine or other antipsychotics should ask their doctor first, as glycine may interact with these drugs.
  6. The body makes glycine, but production may fall short under heavy stress, a poor diet or high toxin exposure (Max Lugavere, on The Doctor's Farmacy).

Why do the sources disagree?

Built from every credited researcher and cited study on each claim.

Leaning for

Glycine is worth taking.

Supports it 3 sources
Partly 3 sources
Leaning for

Glycine before bed improves sleep quality.

Supports it 2 sources
Partly 2 sources

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About This Analysis

This report on Glycine draws on 19 videos (28 hours analyzed) out of 3,700+ hours of recorded interviews with 380 researchers and doctors, plus 48,500+ research studies. Every mention of a claim gets a stance, and the verdict is worked out from all of them, never written by hand.

The full report adds 7 key findings and the dose and protocol. It also has the verdict on every claim, a receipt for each mention, the risks to check, and what combines with it.

Frequently Asked Questions

How much glycine should I take?
1-3g of glycine before bed for sleep (Matthew Walker, on Huberman Lab; Mark Hyman). Start with 1-2g and build up. Up to 5g can come from collagen peptides for connective tissue. It is also taken daily in one longevity drink (Bryan Johnson).
When is the best time to take glycine?
Before bed for sleep (Matthew Walker, on Huberman Lab). It is also taken in the morning as part of one longevity drink (Bryan Johnson). For collagen, timing is flexible, and some evidence suggests taking it with vitamin C may help.
Can I take glycine with magnesium?
Yes. Glycine and magnesium together relax the nervous system and muscles for sleep (Mark Hyman), and both sit in one nightly routine as glycine plus magnesium L-threonate (Peter Attia).
What does glycine do in the body?
Glycine is a conditionally essential amino acid with several jobs. It helps sleep (Matthew Walker, on Huberman Lab). It is one of three building blocks of glutathione, the body's main antioxidant (Mark Hyman). And it makes up roughly one-third of collagen by weight, supplying the building blocks for skin, tendons, cartilage and bone (Layne Norton, on Huberman Lab).
Does glycine have side effects?
Glycine is very well tolerated, and side effects are rare at usual doses of 1-5g. Very high doses above 10g may cause mild stomach upset, nausea or soft stools, so start with 1-2g and build up. Glycine may also lower blood pressure, so people on blood pressure drugs should monitor it.

Common Questions

Does glycine help with sleep?

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Unlock the Full Report

Get dosages, timing and the verdict on every claim with its receipts for Glycine.