Methionine
Methionine is an essential amino acid used as a dietary supplement and therapeutic agent. It is primarily indicated for liver protection, particularly in cases of acetaminophen overdose, and for urinary acidification therapy. This medication provides sulfur-containing amino acids necessary for various metabolic processes in the body.
Methionine is an essential amino acid supplement used for liver support and urinary acidification.
Key facts at a glance
- ATC
- V03AB26
- RxNorm
- 6854
- Generic
- Methionine
- Class
- atc-v03
- Brands
- Freamine III 10, Clinimix E 4.25/10, Aminosyn II 8.5 % with Electrolytes, Sulfite-Free, Aminosyn 8.5 % with Electrolytes, Sulfite-Free, Trophamine 10 %, Trophamine 6 %, Plenamine, Prosol, PremaSol, Aminosyn II 15%, Aminosyn II 8.5 %, Sulfite-Free, Aminosyn II 10 %, Aminosyn-HBC 7 %, Sulfite-Free, Aminosyn-PF 10 %, Sulfite-Free, Clinimix E 4.25/5
- Availability
- otc
- Pregnancy
- C
- Lactation
- safe
- Half-life (h)
- 2.5
- Onset (min)
- 30
- Duration (h)
- 4
- Routes
- oral, intravenous
- Forms
- tablet, capsule, powder, injection, intravenous solution
- Regions
- United States, European Union, Canada, United Kingdom, Australia
- Monitoring
- liver enzymes, renal function, plasma amino-acid levels
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
first trimesteruse under medical supervision
use only if clearly needed for parenteral nutrition support
regular prenatal monitoring
Use with caution and monitor for adverse effects.
pregnancy
third trimesteruse under medical supervision
continue only if benefits outweigh potential risks
regular fetal monitoring
Use with caution and monitor for adverse effects.
lactation
breastfeedingno adjustment needed
generally considered compatible with breastfeeding
standard lactation monitoring
pediatric_age
neonatesweight-based dosing required
use only in parenteral nutrition formulations designed for neonates
close monitoring of amino acid levels and growth parameters
Use with caution and monitor for adverse effects.
pediatric_age
childrenage-appropriate dosing
use as component of balanced parenteral nutrition
monitor growth and development
geriatric
elderlystandard dosing with monitoring
assess renal and hepatic function before use
monitor renal and hepatic function periodically
renal_impairment
mild renal impairmentmonitor amino acid levels
use with caution and monitor renal function
regular monitoring of renal function and amino acid levels
Use with caution and monitor for adverse effects.
hepatic_impairment
mild hepatic impairmentmonitor liver function
use under medical supervision with monitoring
monitor liver function tests and amino acid levels
Use with caution and monitor for adverse effects.
Statistics and clinical data
Drug class
Methionine is classified as an essential amino acid used in parenteral nutrition
Common uses
Used in amino acid injection solutions for patients unable to receive oral nutrition
Commonly used in parenteral nutrition since
Historical prescribing information for amino acid injections containing methionine
Common administration route
Administered via IV as component of amino acid solutions in parenteral nutrition
Methionine is used for liver protection in acetaminophen (paracetamol) overdose, urinary acidification, and as a dietary supplement in cases of amino acid deficiency. It may also be used in some cases of depression and chronic liver disease as supportive therapy.
As an essential amino acid, methionine serves as a building block for proteins and is involved in methylation reactions. In acetaminophen overdose, it helps replenish glutathione stores in the liver, protecting hepatocytes from toxic metabolites. It also has mild acidifying effects on urine.
Methionine is generally well-tolerated but may cause gastrointestinal upset in some individuals. It should be used with caution in patients with liver or kidney impairment, acidosis, or cardiovascular disease. Since it is an essential amino acid, adequate dietary intake is important. Consult a healthcare provider before use, especially if taking other medications or having pre-existing medical conditions.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 27, 2026. · Read our editorial policy