✓ No active regulatory warningsFDA MedWatch, EMA EudraVigilance, WHO VigiBase, WADA Prohibited List · 2026-05-29
Updated: 2026-05-29 · v2.0 · Prof. G. Pkhakadze, MD, MPH, PhDCiteEditorial
📰Read the full L-Methionine evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.
2
Conditional
L-Methionine
L-Methionine
Conditionally SafeModerateAmino Acids
RDA
Typical 500–1,500 mg
Target
<15 µmol/L
Upper limit
No UL
Products
7
Dosage by population group — reference
🔗 Best with: SAMe, Vitamin B6, Vitamin B12, Folate✅ USP Verified, NSF Certified for Sport, Informed Sport
⚠ EXCESS → elevated homocysteine (CVD risk) [2]
⚠ Always co-supplement with B6 + B12 + folate [2]
⚠ SAMe is more direct for methylation/depression [2]
ℹ️ Not obtained from food. Obtained as part of dietary protein rather than tracked individually toward a daily target.
🔬 Lab interpreter
Recommended test
Plasma homocysteine
Reference range / target
<15 µmol/L
When to test
4–8 weeks after starting [2].
MUST monitor with methionine supplementation [2].
Full lab monitoring ↓
⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
Methionine is the universal translation initiator and SAMe precursor. EXCESS RAISES HOMOCYSTEINE — always co-supplement with B6 + B12 + folate. For methylation: SAMe is more direct. For depression: use SAMe (more evidence). Methionine's main supplemental uses: UTI acidification and as cysteine/glutathione precursor [1] [2].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: See guidance
Essential AA. Monitor homocysteine if supplementing [1].
👦 Pediatric: See guidance
Essential nutrient [1].
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose

How to take

🍽 Timing: Divided doses [1].
💊 With food: With food [1].
🚫 Avoid: Excess without B vitamin co-supplementation (homocysteine risk) [2].
2 Which form?
FormBioavailabilityVeganCost
['L-Methionine capsules', 'common', '500 mg. 500–1,500 mg/day [1].']StandardCheck label
3 Common questions
Does methionine raise homocysteine? ▼
YES — excess methionine → homocysteine (via SAMe → SAH pathway). Always supplement with B6 + B12 + folate to support homocysteine clearance [2].
Methionine vs SAMe? ▼
For methylation support: SAMe is the direct methyl donor (more efficient). Methionine is the precursor. For depression: SAMe has much more evidence [2].
4 Clinical evidence

Strong

Methionine → SAMe → methylation reactions: foundational biochemistry [1]. Methionine → homocysteine: excess raises homocysteine [2]. HIGH

Moderate

UTI urine acidification [1]. Acetaminophen adjunct (cysteine/glutathione precursor) [1]. MODERATE

Insufficient

Depression (use SAMe instead — more direct) [2]. Liver support [1]. Athletic performance [1]. LOW
5 Safety, toxicity & adverse events

Relative

⚠ Raises homocysteine — caution in cardiovascular disease and ensure adequate B6/B12/folate
⚠ Liver disease — caution with high doses
⚠ Schizophrenia — high doses may worsen symptoms (older reports)
⚠ Pregnancy — avoid high supplemental doses

🚩 Red flags

● Supplementing methionine without B6/B12/folate — homocysteine will rise [2]
● CVD patient + excess methionine — homocysteine concern [2]
6 Interactions

Drug interactions

Levodopa Minor
Mechanism: May interfere with levodopa. [1]
Effect: Reduced efficacy. [1]
Action: Monitor [1].

Supplement synergies

B6 + B12 + Folate · 50 mg B6 + 500 µg B12 + 400 µg folate
ESSENTIAL: clear methionine-derived homocysteine [2].
7 Regulatory
United States: GRAS. Supplement [1].
8 US supplement products
7
on-market products containing L-Methionine (NIH DSLD)

Brands carrying L-Methionine (2)

Click a brand to see its L-Methionine products.
Or browse all 7 products in one list →
9 Frequently paired with
L-Phenylalanine 4 sharedL-Tryptophan 4 sharedL-Lysine 4 sharedL-Leucine 4 shared
L-Methionine vs SAMeL-Methionine vs Vitamin B6
10 Cite this page
Vancouver: Pkhakadze G. L-Methionine — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Jul 15]. Available from: https://supplement.ge/ingredients/l-methionine/
APA 7th: Pkhakadze, G. (2026). L-Methionine — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/l-methionine/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: January 2027
References: 2 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "L-Methionine — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/l-methionine/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG