Cysteine
Cysteine is a semi-essential amino acid that plays a role in protein synthesis and the production of glutathione, an important antioxidant. It is used as a dietary supplement and in certain medical formulations to support detoxification, mucolytic therapy, and as a component of parenteral nutrition.
Cysteine is an amino acid supplement used to support antioxidant production, detoxification, and as a component in nutritional therapy.
Key facts at a glance
- ATC
- unclassified
- RxNorm
- 3256
- Generic
- Cysteine
- Class
- unclassified
- Brands
- Freamine III 10, Trophamine 10 %, Trophamine 6 %, Elcys, Nouress, PremaSol, Hepatamine 8, ProcalAmine 3
- Availability
- otc
- Pregnancy
- C
- Lactation
- unknown
- Half-life (h)
- 2
- Onset (min)
- 0
- Duration (h)
- 0
- Routes
- intravenous, oral
- Forms
- injection, solution, capsule, tablet, powder
- Regions
- United States, Canada, European Union, Australia
- Monitoring
- liver function tests, renal function, serum electrolytes, acid-base status, 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.
Used as a dietary supplement to support overall amino acid intake, sometimes in parenteral nutrition formulations, and as a mucolytic agent (typically as N-acetylcysteine) to help break down mucus in respiratory conditions.
As an amino acid, cysteine contributes to protein structures in the body. It serves as a precursor to glutathione, supports detoxification processes, and in its acetylated form acts as a mucolytic by breaking disulfide bonds in mucus proteins.
Generally considered safe when used appropriately as a supplement. May interact with certain medications. Those with cystinuria or kidney stones should use caution. Should only be used under medical supervision when used therapeutically.
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 26, 2026. · Read our editorial policy