Prescription medicine
Cysteine Brand names: Elcys
Cysteine (Elcys) is a prescription medicine with an FDA approval on record since 1986. No generic is listed in FDA's NDC Directory.
- No generic listed
Check it at the source: the cysteine FDA label on DailyMed (effective April 9, 2026, Exela Pharma Sciences, LLC); the NDA 19523 record on Drugs@FDA; every cysteine label on DailyMed.
Highlights of the record
FDA label of April 9, 2026; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026
Used for
From the label: indications and usageELCYS ® is indicated for use as an additive to amino acid solutions to meet the nutritional requirements of newborn infants requiring total parenteral nutrition (TPN);
Forms and strengths
- 10 mg/ml
- 34.5 mg/ml
- 50 mg/ml
Injection (solution); injection.
On the market
- Earliest approval on file
- October 22, 1986 Cysteine Hydrochloride, Hospira; Drugs@FDA’s file, where older or withdrawn approvals can be missing
- Generic approvals
- No generic approved
- Labelers listed (NDC)
- 2 of which 0 under generic applications, 2 under brand applications, repackagers included
- Last listed patent
- March 15, 2039 Nouress injection; not a generic launch date
Supply and safety
- Pharmacy cost (NADAC)
- Not in the survey
- Shortage (FDA)
- No current entry
- Recalls by its makers (FDA)
- 1 since 2023 1 Class I among all firms' recalls; latest October 18, 2023
- FAERS reports
- 24 through July 30, 2026
What is cysteine used for?
From the label: indications and usageELCYS ® is indicated for use as an additive to amino acid solutions to meet the nutritional requirements of newborn infants requiring total parenteral nutrition (TPN); and of adult and pediatric patients with severe liver disease who may have impaired enzymatic processes and require TPN. It can also be added to amino acid solutions to provide a more complete profile of amino acids for protein synthesis. ELCYS ® is a sulfur-containing amino acid indicated to meet the nutritional requirements of newborn infants requiring total parenteral nutrition (TPN); and of adult and pediatric patients with severe liver disease who may have impaired enzymatic processes and require TPN. […]
Source: FDA drug label (ELCYS), Exela Pharma Sciences, LLC, effective April 9, 2026 (SPL set 52317b38-b2e6-4a1c-b5b0-43cada0d205e), via openFDA; the full label on DailyMed
Is there a generic for cysteine (Elcys)?
No generic cysteine is approved (Drugs@FDA, October 8, 2026).
The Orange Book lists no patent for Cysteine Hydrochloride injection; a patent listed only for Nouress injection runs to March 15, 2039. A patent or exclusivity date is not the date a generic goes on sale: court cases and settlements move it either way.
- 1986 earliest approval on file
- 2039 last listed patent
- red ticks recalls
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
Has cysteine been recalled?
The FDA's Enforcement Report lists 1 recall naming cysteine since 2023: 1 Class I (the most serious), 0 Class II, 0 Class III; 1 still ongoing. A recall names products and lots, not every product of the medicine.
| Started | Class | Company | Reason |
|---|---|---|---|
| October 18, 2023 | Class I | Exela Pharma Sciences LLC | Presence of Particulate Matter: Silicone |
Source: FDA Enforcement Report (drug recalls) via openFDA, through October 8, 2026
What does the cysteine label say about other medicines?
The cysteine label names no other medicine on this site. The labels of 1 other medicine name cysteine. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.
Source: FDA drug label (ELCYS), Exela Pharma Sciences, LLC, effective April 9, 2026 (SPL set 52317b38-b2e6-4a1c-b5b0-43cada0d205e), via openFDA; the full label on DailyMed
What do FAERS reports show for cysteine?
The FDA Adverse Event Reporting System holds 24 reports that list cysteine among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 1 are coded as a death and 13 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
What next?
- Cysteine side effects
- the label's list beside FAERS reports
- Check an interaction
- what two or more labels say about each other