An amino acid involved in the urea cycle and nitric-oxide production.
Citrulline is an amino acid that the body does not use to build proteins. It is made mainly in the gut lining and takes a central part in the urea cycle, the pathway that clears ammonia. It is also a stepping stone in the body's production of arginine and nitric oxide.
It is measured as part of a plasma amino acid profile. Levels give insight into the urea cycle and into how well the small intestine is working, since most citrulline is made there. Unusual readings can point to urea cycle disorders or reduced gut function and are interpreted alongside the rest of the panel.
Aniva reads your result against research-backed ranges, not just the lab's wide normal. The reference shown below is specific to this biomarker.
| Group | Adult fasting plasma range |
|---|---|
| Adults | 10 to 45 µmol/L |
Amino acid ranges vary by laboratory and method. They are best read as part of the full plasma amino acid profile, not in isolation.
Recent protein intake, citrulline supplements, fasting state, and time of day affect the result. A fasting morning sample gives the most reliable reading.
Read as part of the full plasma amino acid profile.
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