Drug & supplement interaction

Glycine + Suvorexant

Suvorexant brand name: Belsomra.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Glycine and Suvorexant in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Glycine and Suvorexant

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Suvorexant and Glycine in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Glycine safety at a glance

Glycine overall Use caution Generally well tolerated at typical doses, but long-term safety data are limited.
Pregnancy Use caution Not enough reliable safety data, so it is best avoided unless your doctor approves.
Breastfeeding Use caution Not enough reliable safety data, so caution is advised while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Suvorexant and Glycine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Suvorexant

Interactions in our licensed database are recorded against drug classes, not just single drug names. Suvorexant is filed under 3 classifications — cns depressants, cytochrome p450 3a4 (cyp3a4) substrates, oral drugs. Glycine has documented interactions with 1 drug class — the most serious being clozapine (clozaril) (moderate) — and none of Suvorexant’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Glycine Does Interact With Other Medications

Glycine has 1 moderate known drug interaction in our database — Suvorexant isn’t one of them. If you take anything else, check it against the full list below.

Moderate 1 No known interaction 2,829 (incl. Suvorexant)
Taking anything else?

Check Another of Your Medications Against Glycine

Covers the 2,830 medications we’ve checked against Glycine. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Glycine and Suvorexant May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Drowsiness / Trouble sleeping / Headache reported in 5.7% of FDA reports for Suvorexant Additional detail

    Glycine

    “Mild sedation has occurred rarely with oral use of glycine. Symptoms resolve rapidly with discontinuation of glycine. Irritability, insomnia, fatigue, memory impairment, headache, and sensory impairment have been reported, but any association with glycine is unclear.”

    Glycine · Natural Medicines adverse-effect record, reported in cluster headache.

    3 sources cited
    1. 10252. Heresco-Levy U, Javitt DC, Ermilov M, et al. Efficacy of high-dose glycine in the treatment of enduring negative symptoms of schizophrenia. Arch Gen Psychiatry 1999;56:29-36.. PubMed
    2. 11320. Gusev EI, Skvortsova VI, Dambinova SA, et al. Neuroprotective effects of glycine for therapy of acute ischaemic stroke. Cerebrovasc Dis 2000;10:49-60. PubMed
    3. 92321. Woods SW, Walsh BC, Hawkins KA, Miller TJ, Saksa JR, D'Souza DC, Pearlson GD, Javitt DC, McGlashan TH, Krystal JH. Glycine treatment of the risk syndrome for psychosis: report of two pilot studies. Eur Neuropsychopharmacol. 2013 Aug;23(8):931-40. PubMed

    Suvorexant

    Listed in the ADVERSE REACTIONS section of the FDA label for Suvorexant, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Dry mouth / Diarrhea Additional detail

    Glycine

    “Soft stools, nausea, vomiting, and upper gastrointestinal (GI) tract discomfort have occurred rarely with oral use of glycine. These symptoms resolve rapidly with discontinuation of glycine. Dry mouth has also been reported but any association to glycine is unclear.”

    Glycine · Natural Medicines adverse-effect record, reported in dry mouth.

    4 sources cited
    1. 10252. Heresco-Levy U, Javitt DC, Ermilov M, et al. Efficacy of high-dose glycine in the treatment of enduring negative symptoms of schizophrenia. Arch Gen Psychiatry 1999;56:29-36.. PubMed
    2. 11320. Gusev EI, Skvortsova VI, Dambinova SA, et al. Neuroprotective effects of glycine for therapy of acute ischaemic stroke. Cerebrovasc Dis 2000;10:49-60. PubMed
    3. 92319. Inagawa K, Kawai N, Ono K, Sukegawa E, Tsubuku S, Takahashi M. Assessment of acute adverse effects of glycine ingestion at a high dose in human volunteers. Seikatsu Eisei. 2006; 50:27-32.
    4. 92321. Woods SW, Walsh BC, Hawkins KA, Miller TJ, Saksa JR, D'Souza DC, Pearlson GD, Javitt DC, McGlashan TH, Krystal JH. Glycine treatment of the risk syndrome for psychosis: report of two pilot studies. Eur Neuropsychopharmacol. 2013 Aug;23(8):931-40. PubMed

    Suvorexant

    Listed in the ADVERSE REACTIONS section of the FDA label for Suvorexant. Read the label on DailyMed ›

Reported for Glycine but not commonly for Suvorexant: memory problems, mood changes or irritability, vomiting and tiredness.

Effects for Suvorexant come from the ADVERSE REACTIONS section of its FDA label; effects for Glycine come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 12,800 voluntary FDA FAERS reports for Suvorexant that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Overlapping uses

What Suvorexant Is Prescribed For, and What Glycine Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Suvorexant is a prescription medicine with approved uses on its FDA label. Glycine is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Suvorexant is prescribed for: Belsomra (suvorexant) is used to treat insomnia — specifically, difficulty falling asleep and/or difficulty staying asleep through the night.

Glycine has been studied for:

  • Insomnia studied, not established Glycine has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Glycine for insomnia

    Small clinical studies suggest that oral glycine may modestly improve sleep quality and daytime feelings of fatigue in patients with poor sleep quality or a restricted sleep duration.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Suvorexant on your own; if you are taking Glycine for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Glycine or Suvorexant

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Glycine or Suvorexant, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Suvorexant

This page covers Glycine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Suvorexant page lists 195 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Grapefruit (major).

By severity: 9 major · 147 moderate · 39 minor.

From our pharmacist’s overview on the Suvorexant page

“People take suvorexant (Belsomra) to fall asleep, and the supplements they reach for often promise the same thing, which is exactly the trouble. Of the 195 ingredients with an interaction on file, 78 add their own sedation on top of the drug's, and that theme dominates the 9 rated major, alcohol in any form among them.”

Reviewed by 2 · Jul 18, 2026

Open the Suvorexant interaction page

One more smart check

Taking Glycine as Part of a Dietary Supplement Product? Check It for Interactions

We hold 3,022 real supplement products containing Glycine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Glycine. Even though Glycine itself has no known interaction with Suvorexant, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Glycine and Suvorexant Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Glycine
Top 10%

#75 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Suvorexant
Steady interest

#2,218 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Glycine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Glycine and Suvorexant records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Glycine

What is Glycine?

Glycine
  • Sleep quality and insomnia
  • Relaxation
  • Cognitive function
  • Metabolic health
  • General wellness

Glycine is a non-essential amino acid your body makes on its own and that also appears in protein-rich foods. It is most studied for improving sleep quality, where early research is promising but limited, and it appears generally well tolerated at common doses. Talk with your pharmacist or doctor before starting it, especially if you take other medicines or have a health condition.

Amino acid (made synthetically or by the body) · Powder, capsules, tablets

An interaction check asks whether these two react with each other — it does not ask whether Glycine is a good idea for someone in your situation. Here is what our Glycine record says about it on its own.

Glycine: dosing

There is no official standardized dose of glycine for any health condition. In sleep studies, a few grams taken before bedtime have been used, but the best dose for an individual is not established.The safest approach is to follow the directions on the product label and start with the lowest amount.

From our Glycine monograph — the full record covers uses, side effects and every documented interaction.

Read the full Glycine monograph & all interactions
Medication

About Suvorexant

What Is Suvorexant Used For?

Brand name: Belsomra

Belsomra (suvorexant) is used to treat insomnia — specifically, difficulty falling asleep and/or difficulty staying asleep through the night.

Most-Reported Side Effects for Suvorexant

From FAERS, the FDA’s public side-effect reporting system (12,888 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Nightmare 740 reports
Somnolence 731 reports
Insomnia 680 reports
Abnormal dreams 602 reports
Headache 545 reports
See full Suvorexant drug information
Keep checking

Other Drugs & Glycine

Browse every other medication we’ve checked against Glycine — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
1Moderate
0Minor
2,828No known interaction
1 Moderate 2,828 No interaction
Moderate

1 interaction

No interaction 2,828 drugs checked — show the list

We also checked Glycine against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,828 medications checked with no known interaction — see the full Glycine list.

See the full Glycine interactions page
See every supplement checked against Suvorexant, ranked by severity
Evidence & sources

Glycine References

The 5 references that drive our Glycine monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Heresco-Levy U, Javitt DC, Ermilov M, et al. Efficacy of high-dose glycine in the treatment of enduring negative symptoms of schizophrenia. Arch Gen Psychiatry 1999;56:29-36.. PubMed
  2. Potkin SG, Jin Y, Bunney BG, Costa J, Gulasekaram B. Effect of clozapine and adjunctive high-dose glycine in treatment-resistant schizophrenia. Am J Psychiatry 1999;156:145-7.. PubMed
  3. Gusev EI, Skvortsova VI, Dambinova SA, et al. Neuroprotective effects of glycine for therapy of acute ischaemic stroke. Cerebrovasc Dis 2000;10:49-60. PubMed
  4. Inagawa K, Kawai N, Ono K, Sukegawa E, Tsubuku S, Takahashi M. Assessment of acute adverse effects of glycine ingestion at a high dose in human volunteers. Seikatsu Eisei. 2006; 50:27-32.
  5. Woods SW, Walsh BC, Hawkins KA, Miller TJ, Saksa JR, D'Souza DC, Pearlson GD, Javitt DC, McGlashan TH, Krystal JH. Glycine treatment of the risk syndrome for psychosis: report of two pilot studies. Eur Neuropsychopharmacol. 2013 Aug;23(8):931-40. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Glycine and Suvorexant Together: Common Questions

Is it safe to take Glycine with Suvorexant?
We do not list a known interaction between Glycine and Suvorexant. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Glycine and Suvorexant have any of the same side effects?
Yes — our sources link each of them separately to 5 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Are Glycine and Suvorexant used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Glycine in each. That is a conversation for your prescriber, especially if Suvorexant is being adjusted to a target.
How was the Glycine and Suvorexant combination checked?
Interactions in our licensed database are recorded against drug classes. Suvorexant is filed under 3 classifications, and Glycine has documented interactions with 1 drug class — none of Suvorexant's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Glycine interact with any other medications?
Yes. Glycine has 1 documented drug interaction in our database — Suvorexant is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Suvorexant interact with any supplements?
Yes. Suvorexant has documented interactions with 195 supplements in our database — Glycine is not one of them. The Suvorexant interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Glycine monograph Uses, safety profile, and every drug interaction in one place Suvorexant drug information The full plain-English guide to this medication Suvorexant supplement interactions Every supplement checked against Suvorexant, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Suvorexant and Glycine?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.