L-ARGININE HCL

L-Arginine HCL is often included in cell culture media to support the growth and viability of cells. 
L-Arginine HCL provides a nitrogen source for cell metabolism and protein synthesis, which is crucial for the production of biologics such as monoclonal antibodies, recombinant proteins, and viral vectors in cell culture systems.
L-Arginine HCL is a chemical compound that consists of the amino acid L-arginine bound to hydrochloric acid, forming a salt. 

CAS Number: 1119-34-2
Molecular Formula: C6H15ClN4O2
Molecular Weight: 210.66
EINECS Number: 214-275-1

Synonyms: L-Arginine hydrochloride, 1119-34-2, Arginine Hydrochloride, L-ARGININE HCL, L-Arginine monohydrochloride, Arginine HCl, 15595-35-4, H-Arg-OH.HCl, R-Gene, Argamine, Argivene, Detoxargin, Levargin, Minophagen A, Arginine monohydrochloride, Tivortin, R-gene 10, L-(+)-Arginine monohydrochloride, Arginine, hydrochloride, L-, MFCD00064550, UNII-F7LTH1E20Y, (S)-2-Amino-5-guanidinopentanoic acid hydrochloride, L-Arginine (hydrochloride), NSC 7914, EINECS 214-275-1, Arginine monochloride, F7LTH1E20Y, NSC 203450, L(+)-Arginine hydrochloride, L-Arginine, monohydrochloride, AI3-18300, NSC-7914, NSC-203450, EC 214-275-1, L-Arginine, hydrochloride (1:1), L-Arginine, monohydrochloride, L-, ARGININE, L-, HYDROCHLORIDE, (2S)-2-amino-5-carbamimidamidopentanoic acid hydrochloride, Hydrochloride, arginine, L-(+)-Arginine Hydrochloride, L-arginine, hydrochloride, (2S)-2-amino-5-(diaminomethylideneamino)pentanoic acid;hydrochloride, MFCD00166393, (S)-(+)-2-Amino-5-[(aminoiminomethyl)amino]pentanoic acid monohydrochloride, ARGININE HYDROCHLORIDE (MART.), ARGININE HYDROCHLORIDE [MART.], ARGININE HYDROCHLORIDE (USP-RS), ARGININE HYDROCHLORIDE [USP-RS], R-gene (TN), (+)-L-Arginine hydrochloride, ARGININE HYDROCHLORIDE (EP MONOGRAPH), ARGININE HYDROCHLORIDE [EP MONOGRAPH], L-Arginine hydrochloride (VAN), NSC203450, ARGININE HYDROCHLORIDE (USP MONOGRAPH), ARGININE HYDROCHLORIDE [USP MONOGRAPH], Arginine Hydrochloride [USAN:JAN], C6H15ClN4O2, NSC7914, (S)-(+)-Arginine hydrochloride, L-Argininexhydrochloride, nBu-PArg(20)*HCl, nBu-PArg(50)*HCl, l-arginine monochlorhydrate, nBu-PArg(100)*HCl, Argininine monohydrochloride, SCHEMBL44977, Arginine hydrochloride (USP), HY-N0455AR, CHEMBL1200381, CHEBI:31235, HY-N0455A, DTXSID20883650, L-Arginine hydrochloride (JP17), ARGININE HYDROCHLORIDE [MI], ARGININE HYDROCHLORIDE [USAN], CCG-43265, s3174, ARGININE HYDROCHLORIDE [VANDF], AKOS015906195, AKOS015924214, L-ARGININE HYDROCHLORIDE [JAN], ARGININE HYDROCHLORIDE [WHO-DD], CS-2046, DS-2054, FA15785, L-Arginine (hydrochloride) (Standard), AC-23975, L-ARGININE MONOHYDROCHLORIDE [FCC], ARGININE HYDROCHLORIDE [ORANGE BOOK], DB-029943, A0528, CS-0368604, NS00085581, D01126, D70773, EN300-249105, Arginine Hydrochloride (L-Arginine Hydrochloride), L-Arginine monohydrochloride, Vetec(TM), 98.5%, SR-01000075479-3, Q27277776, L-Arginine hydrochloride, SAJ special grade, >=99.0%, L-Arginine monohydrochloride, BioUltra, >=99.5% (AT), L-Arginine monohydrochloride, Vetec(TM) reagent grade, >=98%, L-Arginine monohydrochloride, reagent grade, >=98% (HPLC), powder, Arginine hydrochloride, British Pharmacopoeia (BP) Reference Standard, Arginine hydrochloride, European Pharmacopoeia (EP) Reference Standard, L-Arginine monohydrochloride, certified reference material, TraceCERT(R), Arginine Hydrochloride, Pharmaceutical Secondary Standard; Certified Reference Material, 214-275-1, L-Arginine monohydrochloride, not synthetic, meets EP, JP, USP testing specifications, suitable for cell culture, 98.5-101.0%, argininemonohydrochloride;argivene;minophagena;monohydrochloride,l-arginin;r-gene;2-amino-5-guanidinovaleric acid monohydrochloride;L(+)-Arginine hydrochloride;ARGININE HYDROCHLORID

L-Arginine HCL is a salt form of L-Arginine, where hydrochloric acid is added to enhance stability and solubility. 
Arginine hydrochloride is a L-alpha-amino acid. 
An essential amino acid that is physiologically active in the L-form. 

L-Arginine HCL might be effective at lowering blood pressure, reducing the symptoms of angina and PAD , and treating erectile dysfunction due to a physical cause.
L-Arginine HCL is a type of arginine, an amino acid that is naturally produced by the body and is also found in various foods. 
In its hydrochloride (HCl) form, it is commonly used in pharmaceuticals and biologics production due to its diverse applications and physiological effects.

L-Arginine HCL is a naturally occurring amino acid that plays an essential role in various metabolic functions, including the synthesis of proteins and the production of nitric oxide, a key molecule involved in blood vessel dilation. When in the form of L-Arginine hydrochloride, the compound is typically used as a supplement to improve blood flow, enhance exercise performance, and support cardiovascular health by increasing nitric oxide levels. 
The hydrochloride component ensures the stability and solubility of L-Arginine in various formulations, particularly in oral and injectable supplements, making it easier for the body to absorb and utilize.

In addition to its cardiovascular benefits, L-Arginine HCL is also commonly used in the medical field to aid in wound healing, support immune function, and assist in the treatment of conditions related to low blood flow, such as erectile dysfunction. 
It is also an ingredient in various products aimed at boosting athletic performance, increasing muscle mass, and improving endurance during physical activity. 
The hydrochloride form of L-Arginine is often preferred because it is more stable and easier to work with compared to other forms of the amino acid, making it more widely available in the form of dietary supplements and pharmaceutical preparations.

L-Arginine HCl can act as a stabilizer in biologics formulations, helping to maintain the stability and integrity of proteins and other biologics molecules during storage and transportation.
L-Arginine HCL can protect against denaturation and aggregation, which are common challenges in the formulation of biologics.
During the production of recombinant proteins, L-Arginine HCl can be used to facilitate protein refolding. Protein refolding is a critical step in the production of biologics, particularly when producing proteins in bacterial expression systems like E. coli, where proteins often fold incorrectly and form insoluble aggregates known as inclusion bodies. 

L-Arginine HCL can help solubilize and refold these proteins into their biologically active conformations.
L-Arginine HCL is an amino acid naturally found in red meat, poultry, fish, and dairy. 
It is necessary for making proteins and is commonly used for circulation.

L-Arginine HCL is converted in the body into a chemical called nitric oxide. 
Nitric oxide causes blood vessels to open wider for improved blood flow. 
L-Arginine HCL also stimulates the release of growth hormone, insulin, and other substances in the body. 

L-Arginine HCL can be made in a lab and used in supplements.
L-Arginine HCL is an amino acid that you can find naturally in foods like fish, meat and nuts. 
L-Arginine HCL is semi-essential (conditional), which means that your body can produce the amino acid, but you also need to include some sources of the amino acid in your diet.

Arginine was first isolated in 1886 from yellow lupin seedlings by the German chemist Ernst Schulze and his assistant Ernst Steiger.
He named it from the Greek árgyros (ἄργυρος) meaning "silver" due to the silver-white appearance of arginine nitrate crystals.
In 1897, Schulze and Ernst Winterstein (1865–1949) determined the structure of arginine.

Schulze and Winterstein synthesized arginine from ornithine and cyanamide in 1899, but some doubts about arginine's structure lingered until Sørensen's synthesis of 1910.
L-Arginine HCL is an amino acid derivative that plays a pivotal role in a variety of physiological processes within the human body. 
L-Arginine HCL serves as a precursor for the production of nitric oxide, a powerful vasodilator that helps relax and widen blood vessels, improving blood flow and oxygen delivery to tissues.

This effect is particularly important for cardiovascular health, as it can assist in lowering blood pressure and reducing the risk of heart disease. 
L-Arginine HCL is often used in both clinical and athletic settings due to its potential to enhance endurance, promote faster recovery, and improve performance during intense physical activity by boosting circulation and nutrient delivery to muscles.
In addition to its cardiovascular benefits, L-Arginine HCL plays a role in the synthesis of other amino acids, such as creatine, which is essential for energy production during high-intensity exercise. 

This contributes to its popularity in sports nutrition and bodybuilding, where it is commonly included in supplements designed to promote muscle growth and reduce muscle fatigue. 
L-Arginine HCL also supports the immune system by enhancing the activity of certain white blood cells and promoting the healing of wounds by stimulating the production of collagen, a vital protein in tissue repair.

The letter L in front of arginine stands for “levorotatory,” which is a chemistry term that means the amino acid didn’t bond with a protein molecule (free form). 
This helps providers categorize amino acids based on how similar they are to the amino acids humans produce in their own bodies. 
The L designates that it easily absorbs into your body because it's most similar to amino acids already in your body.

Amino acids are molecules within your body that produce proteins when they combine with other molecules. An amino acid chain forms a protein. 
Proteins are an essential part of what makes humans function because every cell in the human body contains protein.
L-Arginine HCL is an amino acid, which is a building block of protein.

It’s necessary for the production of nitric oxide, a signaling molecule that’s needed for a variety of bodily processes and functions, including blood flow regulation, mitochondrial function, and cellular communication.
Additionally, L-arginine acts as a precursor to other amino acids, including glutamate, proline, and creatine, and is essential for the health and functioning of your immune system.

L-Arginine HCL is produced in several ways. 
L-Arginine HCL can be synthesized from the amino acid citrulline through the breakdown of body proteins or obtained through dietary protein intake from foods like meat, poultry, dairy, nuts, fish, and soy products.
L-Arginine HCL is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. 

The molecule features a guanidino group appended to a standard amino acid framework. 
At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the amino and guanidino groups are protonated, resulting in a cation. 
Only the l-arginine (symbol Arg or R) enantiomer is found naturally.

Arg residues are common components of proteins. 
L-Arginine HCL is encoded by the codons CGU, CGC, CGA, CGG, AGA, and AGG.
The guanidine group in L-Arginine HCL is the precursor for the biosynthesis of nitric oxide.

Like all amino acids, L-Arginine HCL is a white, water-soluble solid.
It is traditionally obtained by hydrolysis of various cheap sources of protein, such as gelatin.
L-Arginine HCL is obtained commercially by fermentation. 

In this way, 25-35 g/liter can be produced, using glucose as a carbon source.
L-Arginine HCL is classified as a semiessential or conditionally essential amino acid, depending on the developmental stage and health status of the individual.
Preterm infants are unable to synthesize arginine internally, making the amino acid nutritionally essential for them.

Most healthy people do not need to supplement with arginine because it is a component of all protein-containing foods and can be synthesized in the body from glutamine via citrulline.
Additional, dietary arginine is necessary for otherwise healthy individuals temporarily under physiological stress, for example during recovery from burns, injury or sepsis, or if either of the major sites of arginine biosynthesis, the small intestine and kidneys, have reduced function, because the small bowel does the first step of the synthesizing process and the kidneys do the second.

L-Arginine HCL is an essential amino acid for birds, as they do not have a urea cycle.
For some carnivores, for example cats, dogs and ferrets, arginine is essential, because after a meal, their highly efficient protein catabolism produces large quantities of ammonia which need to be processed through the urea cycle, and if not enough arginine is present, the resulting ammonia toxicity can be lethal.
This is not a problem in practice, because meat contains sufficient arginine to avoid this situation.

Animal sources of arginine include meat, dairy products, and eggs, and plant sources include seeds of all types, for example grains, beans, and nuts.
L-Arginine HCL is one of the amino acids the body needs to build muscle and heal wounds. 
The body can produce L-arginine, and people can also get it in their diet.

Melting point: 226–230 °C (lit.)
Alpha: 22 º (c=8, 6N HCl)
Boiling point: 235℃ [at 101,325 Pa]
Bulk density: 1250 kg/m³
Density: 1.42
Vapor pressure: <1 Pa (20 °C)
FEMA: 3819 | L-ARGININE
Storage temp.: 2–8°C
Solubility: H2O: 100 mg/mL
Form: powder
pKa: 1 [at 20 ℃]
Color: white
Odor: odorless
pH Range: 5.5–7
pH: 5.5–7.0 (25℃, 1M in H2O)
Biological source: non-animal source
Optical activity: [α]20/D +22.0±0.5°, c = 5% in 5 M HCl
Water Solubility: Soluble in water. Slightly soluble in hot alcohol.
Sensitive: Hygroscopic
λmax: λ: 260 nm Amax: ≤0.2
λ: 280 nm Amax: ≤0.1
Merck: 14,780
BRN: 3631658
Stability: Stable. Incompatible with strong oxidizing agents.
LogP: -8.5 to -3.24 at 25℃

L-Arginine HCL is considered as a semi essential amino acid. 
In most mammals including humans, L-Arginine HCL synthesis occurs through intestinal-renal axis, from glutamine, glutamate and proline. 
Abnormal levels of L-Arginine HCL is associated with the development of kidney and cardiovascular disease. 

L-Arginine HCL is found to decrease fat mass and visceral adiposity.
L-Arginine HCL has some potential side effects to consider when taking it as a supplement. 
Some of the more common and benign side effects can include: nausea, diarrhea, bloating, and abdominal pain. 

However, L-Arginine HCL may result in some serious complications.
L-Arginine HCL is the immediate precursor of nitric oxide, an important signaling molecule which can act as a second messenger, as well as an intercellular messenger which regulates vasodilation, and also has functions in the immune system's reaction to infection.

L-Arginine HCL is also a precursor for urea, ornithine, and agmatine; is necessary for the synthesis of creatine; and can also be used for the synthesis of polyamines (mainly through ornithine and to a lesser degree through agmatine, citrulline, and glutamate). 
The presence of asymmetric dimethylarginine (ADMA), a close relative, inhibits the nitric oxide reaction; therefore, ADMA is considered a marker for vascular disease, just as L-arginine is considered a sign of a healthy endothelium.

The amino acid side-chain of arginine consists of a 3-carbon aliphatic straight chain, the distal end of which is capped by a guanidinium group, which has a pKa of 13.8, and is therefore always protonated and positively charged at physiological pH. 
Because of the conjugation between the double bond and the nitrogen lone pairs, the positive charge is delocalized, enabling the formation of multiple hydrogen bonds.
L-Arginine HCL is synthesized from citrulline in the urea cycle by the sequential action of the cytosolic enzymes argininosuccinate synthetase and argininosuccinate lyase. 

This is an energetically costly process, because for each molecule of argininosuccinate that is synthesized, one molecule of adenosine triphosphate (ATP) is hydrolyzed to adenosine monophosphate (AMP), consuming two ATP equivalents.
The pathways linking arginine, glutamine, and proline are bidirectional. 
Thus, the net use or production of these amino acids is highly dependent on cell type and developmental stage.

L-Arginine HCL is made by the body as follows. 
The epithelial cells of the small intestine produce citrulline, primarily from glutamine and glutamate, which is secreted into the bloodstream which carries it to the proximal tubule cells of the kidney, which extract the citrulline and convert it to arginine, which is returned to the blood. 
This means that impaired small bowel or renal function can reduce arginine synthesis and thus create a dietary requirement for arginine. 

For such a person, arginine would become "essential".
Synthesis of arginine from citrulline also occurs at a low level in many other cells, and cellular capacity for L-Arginine HCL synthesis can be markedly increased under circumstances that increase the production of inducible nitric oxide synthase (NOS). 
This allows citrulline, a byproduct of the NOS-catalyzed production of nitric oxide, to be recycled to L-Arginine HCL in a pathway known as the citrulline to nitric oxide (citrulline-NO) or arginine-citrulline pathway. 

This is demonstrated by the fact that, in many cell types, nitric oxide synthesis can be supported to some extent by citrulline, and not just by arginine. 
This recycling is not quantitative, however, because citrulline accumulates in nitric oxide producing cells along with nitrate and nitrite, the stable end-products of nitric oxide breakdown.
L-Arginine HCL plays an important role in cell division, wound healing, removing ammonia from the body, immune function, and the release of hormones.

L-Arginine HCL is a precursor for the synthesis of nitric oxide (NO), making it important in the regulation of blood pressure.
L-Arginine HCL is necessary for T-cells to function in the body, and can lead to their deregulation if depleted.
L-Arginine HCL's side chain is amphipathic, because at physiological pH it contains a positively charged guanidinium group, which is highly polar, at the end of a hydrophobic aliphatic hydrocarbon chain. 

Because globular proteins have hydrophobic interiors and hydrophilic surfaces, L-Arginine HCL is typically found on the outside of the protein, where the hydrophilic head group can interact with the polar environment, for example taking part in hydrogen bonding and salt bridges.
For this reason, it is frequently found at the interface between two proteins.
The aliphatic part of the side chain sometimes remains below the surface of the protein.

L-Arginine HCL residues in proteins can be deiminated by PAD enzymes to form citrulline, in a post-translational modification process called citrullination.
This is important in fetal development, is part of the normal immune process, as well as the control of gene expression, but is also significant in autoimmune diseases.
Another post-translational modification of arginine involves methylation by protein methyltransferases.

The compound has also been explored for its therapeutic potential in treating conditions like erectile dysfunction, where its ability to increase nitric oxide levels helps improve blood flow to the genital area. 
Additionally, L-Arginine HCl is sometimes used in the treatment of certain metabolic disorders and can be a part of a clinical regimen for individuals suffering from conditions that impair circulation, such as peripheral artery disease. 
Because of its versatility and potential health benefits, L-Arginine HCl is found in a wide range of pharmaceutical and dietary supplement products aimed at improving both physical performance and overall well-being.

Uses:
L-Arginine HCL is used in the treatment of heart and circulatory diseases. 
It is a precursor of nitric oxide synthesis that induces vasodilation in vivo, there by relaxing blood vessels. 
L-Arginine HCL is also used in the treatment of angina and other cardiovascular problems. 

L-Arginine HCL is an important intermediate in the urea cycle and involved in the detoxification of nitrogenous wastes. 
It is commonly used in cell culture media and drug development.
An essential amino acid for human development. 

Precursor for nitric oxide ammonia detoxicant (hepatic failure); diagnostic aid (pituitary function).
L-Arginine HCL is widely used for its ability to support cardiovascular health by increasing the production of nitric oxide in the body. 
Nitric oxide helps to dilate blood vessels, thereby improving blood flow and oxygen delivery to tissues, which can help lower blood pressure and enhance circulation. 

This is particularly beneficial for individuals with cardiovascular conditions or those seeking to improve their overall heart health. 
Additionally, L-Arginine HCl is frequently used in the treatment of erectile dysfunction, as its vasodilatory effects can help improve blood flow to the genital area, potentially enhancing sexual function in men who suffer from this condition.
L-Arginine HCL is also a popular supplement in the field of sports nutrition and fitness due to its ability to improve exercise performance. 

By increasing nitric oxide levels, it can enhance endurance, delay fatigue, and promote better nutrient and oxygen delivery to muscles during physical exertion. 
This makes it a common ingredient in pre-workout supplements aimed at athletes and bodybuilders, where it contributes to improved workout performance and faster recovery post-exercise. 
Furthermore, L-Arginine HCL is involved in the production of creatine, an important compound for high-intensity energy production, which is why it is often used by athletes looking to improve strength and muscle mass.

Another use of L-Arginine HCl is in wound healing and tissue repair. 
L-Arginine HCL is known to stimulate collagen production, which is essential for the regeneration of skin and other tissues following injury or surgery. 
This makes it useful in medical settings where patients need enhanced tissue repair, especially after burns, surgery, or traumatic injuries.

L-Arginine HCL is also beneficial for those suffering from conditions that result in poor circulation, such as peripheral artery disease or chronic leg ulcers, as it helps to improve blood flow to affected areas, promoting healing and reducing symptoms.
In addition to its physiological benefits, L-Arginine HCL is used in some medical treatments for metabolic conditions, such as in the management of ammonia toxicity in individuals with liver dysfunction. 
It has been studied for its potential to support kidney function and reduce the symptoms of chronic kidney disease, as it can help regulate blood pressure and enhance renal blood flow. 

In combination with other nutrients, L-Arginine HCl may also be employed to support immune function, assist with detoxification processes, and improve overall metabolic health.
L-Arginine HCL is utilized in various therapeutic and health-promoting contexts due to its versatile biochemical properties. 
One of its key applications is in the management of cardiovascular conditions. 

By promoting the production of nitric oxide, L-Arginine HCl helps to relax and widen blood vessels, which improves blood flow and reduces the risk of conditions such as hypertension (high blood pressure) and atherosclerosis (hardening of the arteries). 
This vasodilation effect is particularly useful in improving overall cardiovascular function and is often incorporated into treatments aimed at reducing the risk of heart attacks, strokes, and other cardiovascular diseases.

In clinical settings, L-Arginine HCl has been used as an adjunctive therapy for individuals undergoing recovery after surgeries, particularly those involving the heart or blood vessels. 
L-Arginine HCL aids in post-operative recovery by improving blood circulation to vital organs, which in turn promotes faster healing and reduces the likelihood of complications such as blood clots or delayed wound healing. 
It is also sometimes prescribed to patients recovering from trauma, where enhanced blood flow supports the healing of tissues and the repair of muscle injuries.

Another prominent use of L-Arginine HCl is in the treatment of erectile dysfunction (ED), where it works by boosting nitric oxide levels, which relaxes the smooth muscle in blood vessels and enhances blood flow to the penile tissue. 
This action makes it a popular and effective option for improving sexual performance and treating ED, particularly in cases related to reduced blood flow or other circulatory issues. 
It is also commonly used in combination with other therapies to maximize its efficacy in restoring erectile function.

L-Arginine HCL plays a role in metabolic health by supporting the detoxification processes in the body. 
It is often used in patients with liver dysfunction to help remove ammonia from the bloodstream, as it supports the conversion of ammonia into urea for excretion by the kidneys. 
This is particularly helpful for individuals with cirrhosis or other liver conditions where ammonia buildup is a concern. 

Furthermore, it is sometimes incorporated into treatments aimed at managing metabolic conditions such as type 2 diabetes, as it has been shown to improve insulin sensitivity and support overall metabolic function.
In addition to its roles in improving circulation, L-Arginine HCl is valued for its contribution to athletic performance and muscle recovery. 
As a precursor to creatine, L-Arginine helps enhance energy production during high-intensity activities, allowing athletes and bodybuilders to train longer and recover more quickly after strenuous exercise. 

L-Arginine HCL also supports the muscle-building process by improving nutrient delivery to muscle tissues, which can contribute to increased muscle mass and strength over time. 
For those involved in endurance sports, it can help improve stamina by reducing the onset of fatigue and promoting efficient oxygen use during prolonged physical activity.
L-Arginine HCl has also been researched for its potential benefits in treating chronic conditions such as chronic obstructive pulmonary disease (COPD) and asthma, where it may help improve lung function by enhancing blood flow to the lungs and improving oxygen exchange. 

Additionally, it has shown promise in improving the symptoms of conditions such as sickle cell disease, where its ability to increase nitric oxide production can help reduce the frequency and severity of pain crises.
L-Arginine HCL is used in some specialized medical and research settings for its ability to modulate immune function. 

L-Arginine HCL can help stimulate the production of certain cytokines and white blood cells, enhancing the body's natural immune response. 
This makes it a useful addition to certain immunotherapy regimens or as part of a comprehensive treatment for immune deficiencies or disorders.
L-Arginine HCL’s broad range of uses in cardiovascular health, metabolic function, athletic performance, and therapeutic treatments highlights its importance as a versatile supplement and pharmaceutical agent with diverse applications across various medical disciplines.

Intravenously administered L-Arginine HCL is used in growth hormone stimulation tests[40] because it stimulates the secretion of growth hormone.
A review of clinical trials concluded that oral arginine increases growth hormone, but decreases growth hormone secretion, which is normally associated with exercising.
However, a more recent trial reported that although oral L-Arginine HCL increased plasma levels of L-arginine it did not cause an increase in growth hormone.

Safety Profile:
Moderately toxic by intraperitoneal route mildly toxic by ingestion. 
An experimental teratogen when heated to decomposition it emits very toxic fumes of NOx and HCl.
High doses of L-Arginine HCl can lead to gastrointestinal discomfort, including symptoms like bloating, diarrhea, nausea, and abdominal cramps. 

These symptoms are typically more pronounced when the supplement is taken on an empty stomach or in excessive amounts.
L-Arginine HCL is known to promote vasodilation by increasing nitric oxide levels, which can lower blood pressure. 
While this can be beneficial for individuals with hypertension, it can pose a risk for people who already have low blood pressure or are taking medications to lower their blood pressure. 

This combination could result in hypotension (abnormally low blood pressure), which can cause dizziness, fainting, and other symptoms related to insufficient blood flow.
L-Arginine HCL can interact with several types of medications. 
L-Arginine HCL may enhance the effects of blood pressure-lowering medications, leading to a dangerous drop in blood pressure. 

It may also interact with certain erectile dysfunction medications (such as sildenafil) by intensifying their vasodilatory effects, which can further lower blood pressure. 
Additionally, L-Arginine HCL may interfere with medications that affect blood clotting, such as anticoagulants or antiplatelet drugs, increasing the risk of bleeding.
L-Arginine HCL supplementation can lead to an imbalance in electrolytes, particularly potassium. 

This can result in symptoms such as muscle weakness, fatigue, or irregular heart rhythms. 
Individuals with kidney problems or those who are on medications that affect potassium levels should be cautious when using L-Arginine HCl.

L-Arginine HCL has been shown to potentially trigger outbreaks of herpes simplex virus (HSV) in individuals who are prone to cold sores or genital herpes. 
This is because arginine is thought to support the replication of the herpes virus, although the evidence is not conclusive. 
Individuals with a history of herpes should consult with a healthcare provider before using L-Arginine supplements.