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Dietary supplement

Glycine Ingredients & Drug Interactions

by NOW

Glycine label
See full label image
Powder Category: Amino Acid/protein
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Glycine against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Glycine is a dietary supplement by NOW with 1 active ingredient. Its ingredients are commonly taken for sleep quality and insomnia, relaxation, cognitive function.Based on those ingredients, 1 medication has a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Glycine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Glycine by NOW

Ask about any prescription or over-the-counter medication and we check it for interactions with Glycine by NOW — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Glycine by NOW

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains 1 active ingredient: glycine, a simple amino acid your body naturally produces. Glycine plays a role in protein synthesis and several other body functions.

There are no other inactive ingredients listed for this powder.

Does it work?

Not established
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see Glycine's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: Neurotransmitter support, restful sleep, nervous system.
  • We looked for evidence on: Insomnia, Cognitive function, Physical performance, Sleep quality, Relaxation, General wellness.
  • The closest evidence on file: Glycine is rated "Insufficient Reliable Evidence To Rate" for Cognitive function (Natural Medicines).
  • Also on file: Glycine is rated "Insufficient Reliable Evidence To Rate" for Insomnia, Physical performance.

Glycine is possibly effective for schizophrenia — though as noted above, combining it with clozapine may actually worsen symptoms, so that's not a straightforward use case. For other conditions listed in our data — 3-phosphoglycerate dehydrogenase (3-PGDH) deficiency, ADHD, benign prostatic hyperplasia (enlarged prostate), and cystic fibrosis — we don't have enough reliable evidence to say whether it works.

The evidence, ingredient by ingredient Glycine

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Glycine is generally well tolerated at typical doses, but long-term safety data are limited. A small number of people have reported mild sedation, which goes away quickly when they stop taking it.

Digestive side effects like soft stools, nausea, vomiting, and stomach discomfort have also been reported rarely and resolve when use stops. Other symptoms like irritability, insomnia, fatigue, memory issues, headache, dry mouth, and sensory changes have been reported, though it's unclear whether they're actually caused by glycine.

Not enough reliable safety data exist for pregnancy or breastfeeding, so it's best avoided unless your doctor approves. Talk with your doctor or pharmacist if you're pregnant, planning to become pregnant, or breastfeeding before starting this supplement.

Side effects, ingredient by ingredient Glycine

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Glycine.
  • The most serious interaction on file is rated Moderate.
  • For scale: 1 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Check clozapine (Clozaril) before you start. If you take this antipsychotic, adding glycine may make it less effective and could worsen schizophrenia symptoms.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

NOW Glycine is a straightforward single-ingredient supplement. If you take clozapine for schizophrenia, do not use this product without your doctor's approval — the interaction could worsen your symptoms.

For anyone else, check your medications with the tool on this page before starting.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated May 23, 2024.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Glycine, straight from the product label.

Brand NOW
Barcode (UPC) 733739002259
Net contents 1 Pound(s); 454 Gram(s)
Market status On market
Date entered into DSLD May 23, 2024
DSLD ID 314374
Product type Amino Acid/protein
Supplement form Powder
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Kosher, Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Glycine by NOW, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Gram(s)
Maximum serving Sizes:
3 Gram(s)
Servings per container
151
UPC/BARCODE
733739002259
IngredientAmount% DV
Calories10 Calorie(s)--
Glycine3 Gram(s)--

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Suggested Usage: Take 1/4 - 3/4 level teaspoon daily mixed in water or juice, preferably on an empty stomach.

Formula

Glycine is the smallest and simplest amino acid, making it versatile for use in a wide range of functions. Glycine is necessary for the production of glutathione, DNA, creatine, bile, hemoglobin, and most proteins. It also helps to promote glycogen storage, thereby making glucose readily available for energy production. Glycine also functions as a calming neurotransmitter in the brain, where it facilitates nerve impulses and is important for the maintenance of healthy sleep patterns.

Glycine Pure powder

Triangle K (Kosher)

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Precautions

Caution: For adults only.

Consult physician if pregnant/nursing, taking medication, or have a medical condition.

Keep out of reach of children.

Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, tree nut or sesame ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.

Formulation

Natural color variation may occur in this product. Neurotransmitter Support Promotes Restful Sleep Nervous System Support Pharmaceutical Grade

Vegetarian/Vegan

Packaged and quality tested in the USA.

Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, tree nut or sesame ingredients.

Seals/Symbols

Non-GMO

Triangle K (Kosher)

GMP Quality Assured

FDA Statement of Identity

A Dietary Supplement

General Statements

Amino Acids Family owned since 1968.

Storage

This product is sold by weight not volume. Store in a cool, dry place after opening.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Glycine by NOW label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Glycine label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Glycine by NOW

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Gram(s) Dosage formPowder Servings per container151 Amounts shown are per serving.

Glycine

Interacts with
1 drug
3 Gram(s) per serving

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 q...

Glycine monograph & interactions
Interaction report

Glycine by NOW Drug Interactions

Want to check YOUR meds against Glycine?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
1Drugs
1 Moderate

Ingredients driving the most interactions

Glycine 1

Individual Drug Interactions

The ingredients in Glycine interact with 1 drug. Click any drug to see the details.

1 of the 1 ingredient in Glycine interact with drugs. Each result below shows which ingredient is responsible. Glycine

Each ingredient & the kinds of drugs it affects

For each ingredient in Glycine with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Glycine1 drug type · 1 drug

Clozapine (Clozaril)

Theoretically, glycine might decrease the effectiveness of clozapine.
One small clinical study in patients with schizophrenia shows that adding glycine to clozapine therapy worsens symptoms of schizophrenia when compared with clozapine alone. The mechanism of this interaction is unclear.

Likelihood Probable Evidence B
Glycine full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Glycine, from the product label.

NOW

See all NOW products
Name
NOW FOODS
Street Address
395 S. Glen Ellyn Rd.
City
Bloomingdale
State
IL
ZipCode
60108
Web Address
nowfoods.com
Pharmacist Counseling Corner

Glycine by NOW: Common Questions

Does Glycine by NOW interact with any medications?
Yes. Based on its ingredients, Glycine has a known interaction with 1 medication. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Glycine contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
What is glycine used for?
Glycine is an amino acid that our data shows is possibly effective for schizophrenia. It's also been studied for ADHD, enlarged prostate, a rare metabolic condition called 3-PGDH deficiency, and cystic fibrosis, but we don't have enough evidence yet to say whether it actually works for those.
Will glycine make me drowsy?
A small number of people have reported mild sedation with glycine, but it goes away quickly when they stop taking it. Most people don't experience this side effect.
Can I take this while I'm pregnant or breastfeeding?
There isn't enough reliable safety data for pregnancy or breastfeeding, so it's best avoided unless your doctor approves. Talk with your doctor or pharmacist to discuss whether it's right for you in those situations.
Are there any inactive ingredients or fillers in this powder?
No — this product is glycine only, with no other inactive ingredients listed.
What side effects might I experience?
Most side effects are rare and go away when you stop taking it. They may include mild sedation, soft stools, nausea, stomach discomfort, and dry mouth. A few people have also reported irritability, insomnia, fatigue, memory issues, or headache, though it's unclear if glycine actually causes those.

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

Not sure if Glycine is safe with your meds?

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Glycine label
Go deeper

The Full Monographs Behind Glycine’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Glycine

Interacts with 1 drug

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 promisin...

Read the full Glycine monograph →
Sources

Sources & How We Checked

Glycine's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 5 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Glycine 5 references
  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

See these in context on the Glycine monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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