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Dietary supplement

Pure L-Glutamine Powder Ingredients & Drug Interactions

by Doctor's Best

Powder Category: Amino Acid/protein
Most serious interaction: Moderate
The interaction bottom line Most serious interaction: Moderate

Pure L-Glutamine Powder is a dietary supplement by Doctor's Best with 1 active ingredient. Its ingredients are commonly taken for muscle recovery and sports performance, gut health and 'leaky gut', recovery from severe illness or injury.Based on those ingredients, 50 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are L-Glutamine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

HelloPharmacist Scorecard of Pure L-Glutamine Powder by Doctor's Best

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

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 is pure L-glutamine, a single amino acid. Glutamine is a building block your body uses for protein, immune function, and gut health.

The powder form lets you control your dose and mix it into drinks or food. There are no other active ingredients — just the glutamine itself and no fillers.

Does it work?

Moderate evidence
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
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: muscle growth, strength, and post-workout recovery.
  • We looked for evidence on: Athletic performance, Exercise-induced muscle damage, Postoperative recovery, Muscle protein synthesis, Muscle endurance, Athletic recovery.
  • The strongest evidence on file: Glutamine is rated "Possibly Effective" for Postoperative recovery (Natural Medicines).
  • Also on file: Glutamine is rated "Possibly Ineffective" for Athletic performance.
  • Also on file: Glutamine is rated "Insufficient Reliable Evidence To Rate" for Exercise-induced muscle damage.

The evidence for L-glutamine is strongest for sickle cell disease, where it's rated effective. For HIV/AIDS-related wasting, postoperative recovery, and recovery from critical illness or trauma, the evidence is rated possibly effective — meaning there's some promise, but we need more research to be certain.

If you're considering glutamine for one of these purposes, your doctor or pharmacist can help you weigh what the current data shows for your specific situation.

The evidence, ingredient by ingredient Glutamine

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.

L-glutamine is generally well tolerated in healthy adults. The most common side effects are digestive: belching, bloating, constipation, diarrhea, flatulence, nausea, vomiting, and stomach pain.

Headache and musculoskeletal pain have also been reported. In rare cases, people have experienced dizziness or mood changes (mania or hypomania) — one person's dizziness resolved when the dose was lowered.

If you have kidney or liver disease, you should take glutamine only under your doctor's supervision. There isn't enough safety data to recommend supplement doses during pregnancy or breastfeeding unless your doctor advises it.

Side effects, ingredient by ingredient Glutamine

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 — Glutamine.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: seizure medications.
  • For scale: 50 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.

If you take anticonvulsant medications (drugs to prevent seizures), check your specific medications with your doctor or pharmacist before using this product. Glutamine is theoretically broken down into a brain chemical that might reduce how well seizure drugs work, though this hasn't been confirmed in people yet.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence for its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

L-glutamine may be worth considering if you have sickle cell disease or are recovering from surgery or critical illness, though talk with your doctor about whether it's right for you. If you take anticonvulsant medications, check with your doctor or pharmacist before starting, since the interaction hasn't been ruled out in humans.

Digestive side effects are common at higher doses, and it's generally well tolerated at standard amounts in healthy people.

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 Dec 14, 2023.

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 Pure L-Glutamine Powder, straight from the product label.

Brand Doctor's Best
Barcode (UPC) 753950004917
Net contents 10.6 Ounce(s); 300 Gram(s)
Market status On market
Date entered into DSLD Dec 14, 2023
DSLD ID 302703
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), Women (not pregnant or lactating), 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 Pure L-Glutamine Powder by Doctor's Best, 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:
5 Gram(s)
Maximum serving Sizes:
5 Gram(s)
Servings per container
60
UPC/BARCODE
753950004917
IngredientAmount% DV
L-Glutamine5 Gram(s)--

Other ingredients: None

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.
Formula

Doctor's Best L-Glutamine Powder contains Glutamine, an amino acid that is a building block of protein. Glutamine is most commonly used to support muscle growth, skeletal muscles and athletic endurance. Supplementing with L-Glutamine allows the body the much-needed amino acids to increase muscle hydration.

Formulation

This is an essential process in the body that supports muscle recovery from high intensity workouts. Helps support muscle mass and strength Helps support muscle hydration Helps support post-workout recovery

Helps support muscle mass, strength, and post-workout recovery

Vegan

Non-GMO Gluten free Soy free

Vegan

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.

Brand IP Statement(s)

Doctor's Best Science-Based Nutrition

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Suggested Adult Use: Add 1 scoop to 8 ounces of juice or protein shake and mix well. For best results, drink 1 hour before exercise. Repeat after exercise or before bedtime, or as recommended by a nutritionally informed physician.

It is recommended to supplement with B vitamins if taking L-glutamine long term.

Precautions

Warning: Avoid using if you are pregnant, nursing or if you have liver problems.

If you are sensitive to monosodium glutamate (MSG), you may be sensitive to glutamine as the body converts glutamine to glutamate.

Storage

Store in a cool dry place.

General Statements

Note: Settling of contents may occur, which may cause slight variations in number of servings.

See for yourself

Pure L-Glutamine Powder by Doctor's Best label

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

What’s inside

The Ingredients in Pure L-Glutamine Powder by Doctor's Best

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

Serving size5 Gram(s) Dosage formPowder Servings per container60 Amounts shown are per serving.

L-Glutamine

Interacts with
50 drugs
5 Gram(s) per serving

Glutamine is the most abundant amino acid in the body and is usually made in your muscles. A prescription form is FDA-approved to help reduce sickle c...

L-Glutamine monograph & interactions

Other (inactive) ingredients: None. These complete the product’s ingredient list but are not active constituents.

Interaction report

Pure L-Glutamine Powder by Doctor's Best Drug Interactions

Want to check YOUR meds against Pure L-Glutamine Powder?

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
50Drugs
50 Moderate

Ingredients driving the most interactions

Each ingredient & the kinds of drugs it affects

For each ingredient in Pure L-Glutamine Powder 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.

L-Glutamine1 drug type · 50 drugs

Anticonvulsants

Theoretically, glutamine might antagonize the effects of anticonvulsant medications.
Glutamine is metabolized to the excitatory neurotransmitter glutamate. Glutamate might have antagonistic effects with anticonvulsant drugs. However, this interaction has not yet been reported in humans.

Likelihood Possible Evidence D
The maker

Brand information

Manufacturer and brand details for Pure L-Glutamine Powder, from the product label.

Doctor's Best

See all Doctor's Best products
Name
Doctor's Best, Inc.
City
Tustin
State
California
ZipCode
92780
Phone Number
(800) 777-2474
Web Address
www.drbvitamins.com
Pharmacist Counseling Corner

Pure L-Glutamine Powder by Doctor's Best: Common Questions

Does Pure L-Glutamine Powder by Doctor's Best interact with any medications?
Yes. Based on its ingredients, Pure L-Glutamine Powder has a known interaction with 50 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Pure L-Glutamine Powder 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.
Is L-glutamine safe to take while pregnant or breastfeeding?
There isn't enough reliable safety data to know for certain. The data rates it as likely safe in pregnancy, but supplement doses while breastfeeding aren't well studied. Talk with your doctor about whether it's right for you and your baby.
What's the most common side effect I might notice?
Digestive issues are the most common — bloating, gas, constipation, or diarrhea. These often happen at higher doses. Headache and mild nausea can also occur. Starting with a lower dose and working up may help.
Does this product work for muscle building or athletic performance?
The evidence we hold is for sickle cell disease, HIV-related wasting, surgery recovery, and critical illness — not for athletic performance or general muscle gain. That doesn't mean it won't help with your goal, just that the data we have doesn't cover it.
Can I take this if I have kidney or liver disease?
You should only take glutamine under your doctor's supervision if you have kidney or liver problems. Talk with them first — they know your specific situation and can advise whether it's safe for you.
What exactly is L-glutamine, and why would I take it?
L-glutamine is an amino acid — one of the building blocks your body uses to make protein and support your immune system and gut. People take it mainly to help with recovery after surgery or serious illness, or for certain conditions like sickle cell disease.

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

Not sure if Pure L-Glutamine Powder 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.

Pure L-Glutamine Powder label
Go deeper

The Full Monographs Behind Pure L-Glutamine Powder’s Ingredients

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

Sources

Sources & How We Checked

Pure L-Glutamine Powder'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 11 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.

Glutamine 11 references
  1. Miller AL. Therapeutic considerations of L-glutamine: a review of the literature. Altern Med Rev 1999;4:239-48..
  2. Bozzetti F, Biganzoli L, Gavazzi C, et al. Glutamine supplementation in cancer patients receiving chemotherapy: a double-blind randomized study. Nutrition 1997;13:748-51.. PubMed
  3. Mebane AH. L-Glutamine and mania. Am J Psychiatry 984;141:1302-3.
  4. Meldrum BS. Glutamate as a neurotransmitter in the brain: review of physiology and pathology. J Nutr 2000;130:1007S-15S.. PubMed
  5. Garlick PJ. Assessment of the safety of glutamine and other amino acids. J Nutr 2001;131:2556S-61S.. PubMed
  6. Chapman AG. Glutamate and epilepsy. J Nutr 2000;130:1043S-5S.. PubMed
  7. Ziegler TR. Glutamine supplementation in cancer patients receiving bone marrow transplantation and high dose chemotherapy. J Nutr 2001;131:2578S-84S.. PubMed
  8. Laviano A, Molfino A, Lacaria MT, Canelli A, De Leo S, Preziosa I, Rossi Fanelli F. Glutamine supplementation favors weight loss in nondieting obese female patients. A pilot study. Eur J Clin Nutr. 2014 Nov;68(11):1264-6. PubMed
  9. Endari (l-glutamine) [package insert]. Torrance, CA: Emmaus Medical,Inc; 2017.
  10. Niihara Y, Miller ST, Kanter J, et al. A Phase 3 Trial of l-Glutamine in Sickle Cell Disease. N Engl J Med 2018;379(3):226-35. doi: 10.1056/NEJMoa1715971.
  11. Ogden HB, Child RB, Fallowfield JL, et al. Gastrointestinal Tolerance of Low, Medium and High Dose Acute Oral l-Glutamine Supplementation in Healthy Adults: A Pilot Study. Nutrients. 2020;12(10):2953. PubMed

See these in context on the Glutamine 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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