L-Methionine Ingredients & Drug Interactions
by Source Naturals
What is this page for?
First and foremost: checking L-Methionine 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
L-Methionine is a dietary supplement by Source Naturals with 1 active ingredient. Its ingredients are commonly taken for acetaminophen (tylenol) overdose support, liver health, urinary tract acidification.We don’t currently list a known drug interaction for its mapped ingredients — but that doesn’t guarantee none exist, so always confirm with your pharmacist.
HelloPharmacist Scorecard of L-Methionine by Source Naturals
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.
What’s inside
Full disclosure
This product contains 1 active ingredient: L-Methionine, an amino acid your body uses to build proteins and produce other important compounds, including substances that support your nervous system and liver function. There are no inactive ingredients listed for this powder.
Does it work?
Not established
The evidence for L-Methionine is mixed and incomplete in our data. It's rated possibly effective for reducing the risk of neural tube birth defects.
For acetaminophen poisoning, hay fever, asthma, colorectal cancer, and other uses listed, the evidence is insufficient to rate — meaning we don't have enough reliable data to say whether it works for those purposes.
How safe is it?
Well-documented data
L-Methionine from food is well tolerated. High-dose supplements, though, may cause dizziness, drowsiness, headache, irritability, vomiting, or low blood pressure, and should be used only with medical guidance.
Rare serious effects include brain swelling and liver-related confusion — these are uncommon but real. The supplement may also raise your homocysteine (a compound linked to heart disease risk) and increase calcium in your urine.
For pregnancy, safety data on supplement doses hasn't been proven, so talk with your doctor before taking high-dose methionine if you're pregnant or planning to be. Breastfeeding safety at supplement doses is also not well studied — check with your pharmacist or doctor for personalized advice.
Meds to double-check
No known interactions
No interactions are documented in our data for L-Methionine with the ingredients we could check. That said, because high-dose methionine can lower blood pressure, let your doctor or pharmacist know you're taking it if you use blood-pressure medication.
The bottom line
Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. No medication interactions are currently documented, and safety information is well characterized.
L-Methionine may be worth discussing with your doctor if you're interested in it for neural tube defect prevention or another specific reason, especially if you have high blood pressure, heart disease, or a history of vascular problems. Stick with food amounts, and get your provider's sign-off before taking supplements, particularly during pregnancy or breastfeeding.
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 Aug 23, 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
General information
Key facts about L-Methionine, straight from the product label.
| Brand | Source Naturals |
|---|---|
| Barcode (UPC) | 021078001454 |
| Net contents | 3.53 Ounce(s); 100 Gram(s) |
| Market status | On market |
| Date entered into DSLD | Aug 23, 2023 |
| DSLD ID | 295948 |
| Product type | Amino Acid/protein |
| Supplement form | Powder |
| Dietary claims / uses | Nutrient, All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar Free |
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 L-Methionine by Source Naturals, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Calories | 5 Calorie(s) | -- |
| L-Methionine | 1.5 Gram(s) | -- |
Tap any ingredient to jump to its full detail below.
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.
FDA Statement of Identity
Amino Acid Supplement
Formulation
Free-form powder
Hypoallergenic: contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, preservatives, or artificial color, flavor, or fragrance.
Hypoallergenic: contains no yeast, dairy, egg, gluten, corn, soy or wheat.
Formula
L-Methionine is an essential sulfur-containing, free-form amino acid. It contributes to the synthesis of S-adenosyl-L-methionine (SAMe), which is necessary for normal brain function, and L-cysteine, which is a component of glutathione, an important antioxidant molecule in the body. L-Methionine is also a transporter of the antioxidant mineral, selenium.
Suggested/Recommended/Usage/Directions
Suggested Use: 1/4 to 1/2 teaspoon daily between meals. If you experience stomach irritation, take with meals.
Precautions
Note: If you are pregnant, may become pregnant, or breastfeeding, consult your health care professional before using this product.
Do not use if either tamper-evident seal is broken or missing.
Keep out of the reach of children.
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)
Copyright Source Naturals, Inc.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Methionine by Source Naturals label
The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.
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)The Ingredients in L-Methionine by Source Naturals
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size0.37 Gram(s) Dosage formPowder Servings per container66 Amounts shown are per serving.
L-Methionine
No knowninteractions
Methionine is an essential amino acid that your body needs for protein building and many basic chemical reactions. Most people get enough from a norma...
L-Methionine monograph & interactionsL-Methionine by Source Naturals Drug Interactions
We don’t currently list any known drug interactions for the mapped ingredients in L-Methionine. This doesn’t guarantee none exist — always confirm with your pharmacist before combining a supplement with your medications.
Brand information
Manufacturer and brand details for L-Methionine, from the product label.
Source Naturals
- Name
- Source Naturals, Inc.
- Street Address
- P. O. Box 2118
- City
- Santa Cruz
- State
- CA
- ZipCode
- 95062
- Web Address
- www.sourcenaturals.com
L-Methionine by Source Naturals: Common Questions
Does L-Methionine by Source Naturals interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
What does L-Methionine do?
Is L-Methionine safe to take?
Can I take L-Methionine if I'm pregnant or breastfeeding?
What side effects might I experience?
Will this interact with my medications?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Methionine is safe with your meds?
Our pharmacists answer your medication & supplement questions — free.
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.
The Full Monographs Behind L-Methionine’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Sources & How We Checked
L-Methionine'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.
- NIH Dietary Supplement Label Database (DSLD) — The official product label on file for this supplement.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference behind the ingredient interaction data.
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 12 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.
Methionine 12 references
- La Vecchia C, Negri E, Franceschi S, Decarli A. Case-control study on influence of methionine, nitrite, and salt on gastric carcinogenesis in northern Italy. Nutr Cancer 1997;27:65-8. PubMed
- Btaiche IF, Khalidi N. Parenteral nutrition-associated liver complications in children. Pharmacotherapy 2002;22:188-211.. PubMed
- Cottington EM, LaMantia C, Stabler SP, et al. Adverse event associated with methionine loading test: a case report. Arterioscler Thromb Vasc Biol 2002;22:1046-50.. PubMed
- Anon. Should methionine be added to paracetamol formulations? Drug Ther Perspect 1997;10:11-3. DOI
- Smulders, Y. M., Rakic, M., Slaats, E. H., Treskes, M., Sijbrands, E. J., Odekerken, D. A., Stehouwer, C. D., and Silberbusch, J. Fasting and post-methionine homocysteine levels in NIDDM. Determinants and correlations with retinopathy, albuminuria, and c
- McAuley, D. F., Hanratty, C. G., McGurk, C., Nugent, A. G., and Johnston, G. D. Effect of methionine supplementation on endothelial function, plasma homocysteine, and lipid peroxidation. J.Toxicol.Clin.Toxicol. 1999;37(4):435-440. PubMed
- Hanratty, C. G., McGrath, L. T., McAuley, D. F., Young, I. S., and Johnston, G. D. The effects of oral methionine and homocysteine on endothelial function. Heart 2001;85(3):326-330. PubMed
- Ward, M., McNulty, H., McPartlin, J., Strain, J. J., Weir, D. G., and Scott, J. M. Effect of supplemental methionine on plasma homocysteine concentrations in healthy men: a preliminary study. Int.J.Vitam.Nutr.Res. 2001;71(1):82-86. PubMed
- Yaghmai, R., Kashani, A. H., Geraghty, M. T., Okoh, J., Pomper, M., Tangerman, A., Wagner, C., Stabler, S. P., Allen, R. H., Mudd, S. H., and Braverman, N. Progressive cerebral edema associated with high methionine levels and betaine therapy in a patient
- Talukdar R, Murthy HV, Reddy DN. Role of methionine containing antioxidant combination in the management of pain in chronic pancreatitis: a systematic review and meta-analysis. Pancreatology 2015;15(2):136-44. PubMed
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press, 2005. Available at: https://doi.org/10.17226 DOI
- Khairan P, Sobue T, Eshak ES, et al. Association of B Vitamins and Methionine Intake with the Risk of Gastric Cancer: The Japan Public Health Center-based Prospective Study. Cancer Prev Res (Phila) 2022;15(2):101-110. PubMed
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