L-CITRULLINE

L-Citrulline is used ameliorating circulatory problems, such as slow wound healing due to diabetes.
L-Citrulline is used raising muscle protein levels, preventing malnourishment in the elderly and possibly improving athletic performance.
L-Citrulline is used treating intestinal problems, including short bowel syndrome, celiac disease and radiation-caused small bowel damage.

CAS Number: 627-77-0 
13594-51-9 (D) 
372-75-8 (L) 
EC Number: 211-012-2
Name: L‑Citrulline (the L‑enantiomer of citrulline) 
Chemical formula: C₆H₁₃N₃O₃
Molar mass: ~175.19 g·mol⁻¹ 

SYNONYMS:
Citrulline, (2S)-2‑Amino‑5‑ureidopentanoic acid, 2-Amino-5-(carbamoylamino)pentanoic acid, L-citrulline, citrulline, 372-75-8, delta-Ureidonorvaline, Sitrulline, N5-Carbamoyl-L-ornithine, (S)-2-Amino-5-ureidopentanoic acid, L-Cytrulline, Citrulline, L-, N(delta)-Carbamylornithine, N5-(Aminocarbonyl)ornithine, N5-carbamoylornithine, alpha-Amino-delta-ureidovaleric acid, N5-(Aminocarbonyl)-L-ornithine, L-2-Amino-5-ureidovaleric acid, L-Ornithine, N5-(aminocarbonyl)-, (2S)-2-amino-5-(carbamoylamino)pentanoic acid, 2-Amino-5-ureidovaleric acid, 29VT07BGDA, 2-Amino-5-uredovaleric acid, CHEBI:16349, Ngamma-carbamylornithine, N(5)-(aminocarbonyl)-L-ornithine, NSC-27425, DTXSID80883373, DTXCID301022909, 206-759-6, (2S)-2-azaniumyl-5-(carbamoylamino)pentanoate, alpha-Amino-gamma-ureidovaleric acid, CHEBI:18211, NSC27425, H-cit-oh, L(+)-citrulline, Ornithine, N5-(aminocarbonyl)-, MFCD00064397, L-citrullin, cit, d-ureidonorvaline, (2S)-2-amino-5-(aminocarbonylamino)pentanoic acid, CIR, L-(+)-Citrulline, C6H13N3O3, (2S)-2-Amino-5-(carbamoylamino)pentanoic Acid (Citrulline), Ornithine, N5-carbamoyl-, L- (8CI), N5-carbamylornithine, N~5~-carbamoyl-L-ornithine, EINECS 206-759-6, NSC 27425, UNII-29VT07BGDA, Cytrulline, Ureidonorvaline, Ureidovalerate, H-Orn(carbamoyl)-OH;L-Citrulline, L-Citruline, Ornithine, N5-carbamoyl-, L-, gammaureidonorvaline, N-carbamylornithine, L-Citrulline, 4, Amino-ureidovalerate, ND-carbamylornithine, N()-carbamylornithine, L-Citrulline (DCF), L-Citrulline, 98%, Ndelta-Carbamylornithine, starbld0002494, Amino-ureidovaleric acid, Ndelta-carbamy-ornithine, CITRULLINE [MI], A-amino-d-ureidovalerate, L-Citrulline (Standard), 2-Amino-5-uredovalerate, 2-Amino-5-ureidovalerate, L-N5-carbamoyl-Ornithine, CITRULLINE [VANDF], bmse000032, bmse000800, bmse000858, CITRULLINE [MART.], CITRULLINE [WHO-DD], A-amino-d-ureidovaleric acid, L-2-Amino-5-ureidovalerate, N(5)-carbamoyl-L-ornithine, SCHEMBL20588, GTPL722, N5-(aminocarbonyl)-Ornithine, L-2-Amino-5-ureido-valerate, L-CITRULLINE [USP-RS], CHEMBL444814, orb1302545, Alpha-amino-delta-ureidovalerate, Alpha-amino-gamma-ureidovalerate, BDBM92903, HY-N0391R, (S)-2-Amino-5-ureidopentanoate, L(+)-2-Amino-5-ureidovalerate, MSK8335, L-2-Amino-5-ureido-valeric acid, L-Citrulline, >=98% (TLC), HY-N0391, pentanoic acid, 2-amino-5-ureido-, L(+)-2-Amino-5-ureidovaleric acid, s3798, SBB012374, AKOS005259571, AKOS006240677, CCG-266398, CS-W019940, DB00155, FC15792, SMP1_000146, NCGC00142602-01, AC-23976, AS-12594, BP-14067, ST069317, (2S)-2-amino-5-(carbamoylamino)pentanoate, (S)-2-amino-5-(aminocarbonyl)aminopentanoate, N(SUP 5)-(AMINOCARBONYL)-L-ORNITHINE, C00327, D07706, D71216, EN300-251063, M03230, (S)-2-amino-5-(aminocarbonyl)aminopentanoic acid, Q408641, L-2-AMINO-5-(CARBAMOYLAMINO)PENTANOIC ACID, EA65B21D-61C4-4748-9E9F-0CF6EDF9A21D, Z1198149761, (S)-2-Amino-5-ureidopentanoic acid,;L-2-Amino-5-ureidovaleric acid, L-Citrulline, United States Pharmacopeia (USP) Reference Standard

L-citrulline is the L-enantiomer of citrulline.
L-Citrulline has a role as an EC 1.14.13.39 (nitric oxide synthase) inhibitor, a protective agent, a nutraceutical, a micronutrient, a human metabolite, an Escherichia coli metabolite, a Saccharomyces cerevisiae metabolite and a mouse metabolite.

L-Citrulline is an enantiomer of a D-citrulline.
L-Citrulline is a tautomer of a L-citrulline zwitterion.
L-Citrulline is an amino acid.

L-Citrulline is made from ornithine and carbamoyl phosphate in one of the central reactions in the urea cycle.
L-Citrulline is also produced from arginine as a by-product of the reaction catalyzed by NOS family.
L-Citrulline's name is derived from citrullus, the Latin word for watermelon, from which it was first isolated.

L-Citrulline is a metabolite found in or produced by Escherichia coli.
L-Citrulline has been reported in Glycine max, Capsicum annuum, and other organisms with data available.
L-Citrulline is a non-essential amino acid.

In hepatocytes, L-citrulline is synthesized in the urea cycle by the addition of carbon dioxide and ammonia to ornithine.
L-citrulline is converted into L-arginine by the enzymes argininosuccinate synthetase and argininosuccinate lyase in the presence of L-aspartate and ATP.

Subsequently, L-arginine is converted to nitric oxide by nitric oxide synthase and L-citrulline is regenerated as a by-product.
L-Citrulline is a small molecule drug with a maximum clinical trial phase of III (across all indications) and has 16 investigational indications.

L-Citrulline is an amino acid.
L-Citrulline is made from ornithine and carbamoyl phosphate in one of the central reactions in the urea cycle.
L-Citrulline is also produced from arginine as a by-product of the reaction catalyzed by NOS family.

L-Citrulline's name is derived from citrullus, the Latin word for watermelon, from which it was first isolated.
L-Citrulline is a metabolite found in or produced by Escherichia coli.
L-Citrulline has been reported in Glycine max, Capsicum annuum, and other organisms with data available.

L-Citrulline is a non-essential amino acid.
In hepatocytes, L-citrulline is synthesized in the urea cycle by the addition of carbon dioxide and ammonia to ornithine.
L-citrulline is converted into L-arginine by the enzymes argininosuccinate synthetase and argininosuccinate lyase in the presence of L-aspartate and ATP.

Subsequently, L-arginine is converted to nitric oxide by nitric oxide synthase and L-citrulline is regenerated as a by-product.
L-Citrulline is a small molecule drug with a maximum clinical trial phase of III (across all indications) and has 16 investigational indications.

L-Citrulline is made from ornithine and carbamoyl phosphate in one of the central reactions in the urea cycle.
L-Citrulline is also produced from arginine as a by-product of the reaction catalyzed by NOS family.
Its name is derived from citrullus, the Latin word for watermelon, from which L-Citrulline was first isolated.

Watermelon is the main food source of L-citrulline. 
The NIH notes that researchers have found that one cup of diced seedless watermelon contains about 365 milligrams of L-citrulline.
L-citrulline concentration can depend on the specific type of watermelon.

Research from 2019 notes that L-citrulline levels are high in the Crimson Sweet and Dixielee varieties of watermelon.
Other foods have much lower levels of L-citrulline than watermelon.

Some examples of other foods containing L-citrulline include:
*other types of melons
*cucumbers
*pumpkins
*squash
*gourds

L-Citrulline, or simply just citrulline, is a nonessential amino acid.
L-Citrulline is an α-amino acid.
L-Citrulline's name is derived from citrullus, the Latin word for watermelon.

Although named and described by gastroenterologists since the late 19th century, L-Citrulline was first isolated from watermelon in 1914 by Japanese researchers Yatarō Koga (古賀彌太郎) and Ryō Ōtake (大嶽了) and further codified by Mitsunori Wada of Tokyo Imperial University in 1930.
L-Citrulline has the formula H2NC(O)NH(CH2)3CH(NH2)CO2H.

L-Citrulline is a key intermediate in the urea cycle, the pathway by which mammals excrete ammonia by converting it into urea.
L-Citrulline is also produced as a byproduct of the enzymatic production of nitric oxide from the amino acid arginine, catalyzed by nitric oxide synthase.

USES and APPLICATIONS of L-CITRULLINE:
L-citrulline is sold as a dietary supplement, usually in powder form.
Advocates suggest that since L-citrulline boosts nitric oxide production, helping arterial function and thus blood flow throughout the body, this might be helpful in treating or preventing various ailments.

L-Citrulline lowers blood pressure in people with elevated blood pressure.
L-Citrulline is used to ease symptoms of mild-to-moderate erectile dysfunction, with fewer risks than Viagra.
L-Citrulline is used ameliorating circulatory problems, such as slow wound healing due to diabetes.

L-Citrulline is used raising muscle protein levels, preventing malnourishment in the elderly and possibly improving athletic performance.
L-Citrulline is used treating intestinal problems, including short bowel syndrome, celiac disease and radiation-caused small bowel damage
L-Citrulline is used various genetic disorders and health conditions such as liver disease, Parkinson's disease and certain dementias.

Some of these assertions are based on animal studies, and like most dietary supplement claims have not been endorsed by the Food and Drugs Administration.
L-citrulline is added to certain energy drinks such as Reign and touted for its thermogenic effects.

L-citrulline may ease symptoms of mild-to-moderate erectile dysfunction (ED).
Scientists say L-citrulline does not work as well as ED drugs such as Viagra.

However, L-Citrulline appears to be a safe option.
L-Citrulline is efficiently turned into L-arginine in the kidneys after supplementation, which makes it a good choice for increasing nitric oxide synthesis in the body.

BIOLOGICAL ROLE of L-CITRULLINE:
L‑Citrulline is a non‑essential α‑amino acid produced by the body, notable as:
An intermediate in the urea cycle (to dispose of ammonia).

A byproduct of nitric oxide synthase when converting L‑arginine to nitric oxide (NO).
Produced in intestinal enterocytes as a marker of gut functional mass.
It is not incorporated into proteins but participates in metabolic signaling and nitrogen disposal.

✅ USES, BENEFITS & MECHANISMS of L-CITRULLINE:
L-Citrulline is sold as a dietary supplement, either as pure L‑citrulline or as citrulline malate (combined with malic acid).
L-Citrulline is used in some clinical settings to support cardiometabolic health, hypertension, and sports nutrition support.

POTENTIAL BENEFITS of L-CITRULLINE:
*Enhanced nitric oxide production, thus aiding vasodilation, blood flow, and circulation.
*May reduce blood pressure, with meta-analyses showing modest reductions (~4–7 mmHg systolic, ~2–4 mmHg diastolic) at doses ≥ 6 g/day.

ADDITIONAL NOTES of L-CITRULLINE:
L-Citrulline malate is often used in sports supplementation—about 56% citrulline by weight (e.g. 8 g malate ≈ 4.5 g citrulline)
Some sources note antioxidant activity and possible protective roles in lipid oxidation (rodent studies).
L-Citrulline can serve as a clinical marker of gut function, especially in intestinal disorders.

L-citrulline is an amino acid found in watermelon.
It is also made in the body.
The body changes L-citrulline into another amino acid called L-arginine.

The name citrulline comes from Citrullus vulgaris, the Latin term for watermelon.
Unlike some amino acids, L-citrulline isn't used to make protein, but it might help increase other chemicals the body needs to make protein.
It might also help improve blood flow and reduce blood pressure.

People use L-citrulline for athletic performance, sickle cell disease, erectile dysfunction (ED), high blood pressure in the lungs, heart disease, and many other conditions, but there is no good scientific evidence to support most of these uses.

USES & EFFECTIVENESS of L-CITRULLINE:
*Possibly Effective for
Athletic performance.
Taking L-citrulline by mouth might help improve some types of exercise performance such as weight lifting.
But L-Citrulline's effects on aerobic exercises such as running are unclear.

*Possibly Ineffective for
Age-related muscle loss (sarcopenia).
Taking L-citrulline by mouth does not seem to increase muscle strength in older adults who regularly exercise.
There is interest in using L-citrulline for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

RELATED COMPOUNDS of L-CITRULLINE:
-Related alkanoic acids    
*N-Acetylaspartic acid
*Aceglutamide
*N-Acetylglutamic acid
*Pivagabine

-Related compounds    
*Bromisoval
*Carbromal

WHY DO PEOPLE TAKE L-CITRULLINE?
L-citrulline boosts nitric oxide production in the body.
Nitric oxide helps your arteries relax and work better, which improves blood flow throughout your body.
This may be helpful for treating or preventing some diseases.

There is some evidence to suggest the supplement could possibly help lower blood pressure in people with elevated blood pressure.
Elevated blood pressure raises your risk for high blood pressure and heart disease.

Definitions for blood pressure levels are:
*Normal blood pressure: less than 120 over less than 80(<120/<80).
*Elevated: 120-129 over less than 80 (120-129/<80).
*Hypertension stage 1: 130-139 or 80-89.
*Hypertension stage 2: greater than 140 or greater than 90 (≥140 or ≥90).

BIOSYNTHESIS of L-CITRULLINE:
L-Citrulline can be derived from: 
*from arginine via nitric oxide synthase, as a byproduct of the production of nitric oxide for signaling purposes.
*from ornithine through the breakdown of proline or glutamine/glutamate.
*from asymmetric dimethylarginine via DDAH.

L-Citrulline is made from ornithine and carbamoyl phosphate in one of the central reactions in the urea cycle.
L-Citrulline is also produced from arginine as a byproduct of the reaction catalyzed by NOS family (NOS; EC 1.14.13.39).
L-Citrulline is also prevalent in trichohyalin at the inner root sheath and medulla of hair follicles, where it is synthesized from arginine.

Arginine is first oxidized into N-hydroxyl-arginine, which is then further oxidized to citrulline concomitant with release of nitric oxide.
L-Citrulline is also made by enterocytes of the small intestine.

FUNCTION of L-CITRULLINE:
L-Citrulline is a metabolic intermediate within the urea cycle, which is the pathway by which mammals excrete ammonia by converting it into urea.
L-Citrulline is also produced as a byproduct of the enzymatic production of nitric oxide from the amino acid arginine, catalyzed by nitric oxide synthase.

In the yeast species Saccharomyces cerevisiae, L-Citrulline is a metabolic intermediate in the latter, cytosolic half of the arginine biosynthesis pathway.
Several proteins contain L-Citrulline as a result of a post-translational modification.

These L-Citrulline residues are generated by a family of enzymes called peptidylarginine deiminases (PADs), which convert arginine into citrulline in a process called citrullination or deimination with the help of calcium ions.

Proteins that normally contain L-Citrulline residues include myelin basic protein (MBP), filaggrin, and several histone proteins, whereas other proteins, such as fibrin and vimentin are susceptible to citrullination during cell death and tissue inflammation.
Circulating L-Citrulline concentration is a biomarker of intestinal functionality.

PHYSICAL and CHEMICAL PROPERTIES of L-CITRULLINE:
Chemical formula: C₆H₁₃N₃O₃
Molar mass: ~175.19 g·mol⁻¹
Appearance: White crystalline powder, odorless
pKa: ~2.508; pKb: ~11.489
log P: –1.373 (hydrophilic, water‑soluble)
Heat capacity (Cₚ): ~232.8 J K⁻¹ mol⁻¹
Standard molar entropy (S°₂₉₈): ~254.4 J K⁻¹ mol⁻¹
CAS Number: Commonly 372‑75‑8 (verify via original databases)
EC Number: None (only for enzyme reactions, not the compound itself)

Formula / Molar Mass: C₆H₁₃N₃O₃ ~175.19 g/mol
pKa / pKb: ~2.508 / ~11.489
log P: –1.373 (highly water-soluble)
Appearance: White, odorless crystalline powder
Key Biological Roles: Urea cycle, nitric oxide production, intestinal health
Major Benefits: Improved circulation, BP support, possible exercise benefit
Supplement Doses: 3–6 g/day (safe short-term), up to 15 g single-dose
Chemical formula: C6H13N3O3
Molar mass: 175.188 g·mol−1
Appearance: White crystals

Odor: Odourless
log P: −1.373
Acidity (pKa): 2.508
Basicity (pKb): 11.489
Thermochemistry: Heat capacity (C): 232.80 J K−1 mol−1
Std molar entropy (S⦵298): 254.4 J K−1 mol−1
Molecular Weight: 175.19 g/mol
XLogP3: -4.3
Hydrogen Bond Donor Count: 4

Hydrogen Bond Acceptor Count: 4
Rotatable Bond Count: 5
Exact Mass: 175.09569129 Da
Monoisotopic Mass: 175.09569129 Da
Topological Polar Surface Area: 118 Ų
Heavy Atom Count: 12
Formal Charge: 0
Complexity: 171
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 1

Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
Compound Is Canonicalized: Yes
Empirical Formula (Hill Notation): C6H13N3O3
CAS Number: 372-75-8
Molecular Weight: 175.19
Beilstein: 1725416
EC Number: 206-759-6

MDL number: MFCD00064397
UNSPSC Code: 12352209
PubChem Substance ID: 24892975
NACRES: NA.32
Physical state: crystalline
Color: white
Odor: No data available
Melting point/freezing point: Melting point/ range: 235,5 °C
Initial boiling point and boiling range: No data available
Flammability (solid, gas): No data available
Upper/lower flammability or explosive limits: No data available

Flash point: Not applicable
Autoignition temperature: No data available
Decomposition temperature: No data available
pH: No data available
Viscosity: Viscosity, kinematic: No data available, Viscosity, dynamic: No data available
Water solubility: No data available
Partition coefficient: n-octanol/water: No data available
Vapor pressure: No data available

Density: No data available
Relative density: No data available
Relative vapor density: No data available
Particle characteristics: No data available
Explosive properties: Not classified as explosive.
Oxidizing properties: none
Other safety information: No data available

FIRST AID MEASURES of L-CITRULLINE:
-Description of first-aid measures
*General advice:
Show this material safety data sheet to the doctor in attendance.
*If inhaled:
After inhalation: 
Fresh air.
*In case of skin contact: 
Take off immediately all contaminated clothing. 
Rinse skin with
water/ shower.
*In case of eye contact:
After eye contact: 
Rinse out with plenty of water. 
Call in ophthalmologist. 
Remove contact lenses.
*If swallowed:
After swallowing: 
Immediately make victim drink water (two glasses at most). 
Consult a physician.
-Indication of any immediate medical attention and special treatment needed.
No data available

ACCIDENTAL RELEASE MEASURES of L-CITRULLINE:
-Environmental precautions:
Do not let product enter drains.
-Methods and materials for containment and cleaning up:
Cover drains. 
Collect, bind, and pump off spills. 
Observe possible material restrictions. 
Take up dry. 
Dispose of properly. 
Clean up affected area.

FIRE FIGHTING MEASURES of L-CITRULLINE:
-Extinguishing media:
*Suitable extinguishing media:
Carbon dioxide (CO2) 
Foam 
Dry powder
*Unsuitable extinguishing media:
For this substance/mixture no limitations of extinguishing agents are given.
-Further information:
Prevent fire extinguishing water from contaminating surface water or the ground water system.

EXPOSURE CONTROLS/PERSONAL PROTECTION of L-CITRULLINE:
-Control parameters:
--Ingredients with workplace control parameters:
-Exposure controls:
--Personal protective equipment:
*Eye/face protection:
Use equipment for eye protection. 
Safety glasses
*Body Protection:
protective clothing
*Respiratory protection:
Recommended Filter type: Filter A 
-Control of environmental exposure:
Do not let product enter drains.

HANDLING and STORAGE of L-CITRULLINE:
-Conditions for safe storage, including any incompatibilities:
*Storage conditions:
Tightly closed. 
Dry.

STABILITY and REACTIVITY of L-CITRULLINE:
-Chemical stability:
The product is chemically stable under standard ambient conditions (room temperature).
-Possibility of hazardous reactions:
No data available