Miracon Science

L-Arginine

Synonym(s): arginine
Nutrient group: Amino acids

Sources and physiological effects

Dietary sources
L-arginine is a proteinogenic amino acid that belongs to the semi-essential amino acids. Under certain circumstances – such as injuries, burns or growth phases – the body is dependent on an additional exogenous supply. L-arginine is widely found in food. Higher amounts of L-arginine are found in pumpkin seeds, peanuts and walnuts. Chicken, pork and salmon also contain significant amounts of L-arginine.
Physiological effects
Nervous system
  • Synthesis of nitric oxide (NO) 
Cardiovascular
  • Vasodilative effect through regulation of vascular tone via NO
  • Antithrombotic by reduction of platelet aggregation 
Fertility
  • Stabilizing effect on sperm DNA by synthesis of spermine
Immune system
  • Increase in lymphocyte formation 
Urea cycle
  • Ammonia excretion - urea cycle 

Recommended intake

Recommended intake according to food labelling regulations  
(=100 % TB marking on label) N/A
Nutrient safety  
UL Long-term daily intake at which no negative health effects are to be expected  N/A
NOAEL Maximum intake,  with no observed adverse effect  N/A
Highest Observed Intake (HOI) Highest dosage published in studies without negative effects (unofficial value) 20 g/d

Detailed information

Arginine, an amino acid with many functions

Most of the 20 amino acids are synthesized in the organism via transamination from the corresponding precursors. It is only in the case of the 9 essential amino acids that the body has no possibility of self-synthesis. Since the amino acid requirement and the ability for endogenous synthesis depend on a multitude of factors, non-essential amino acids can also attain essentiality. These amino acids are called "conditionally essential". For this reason, especially L-arginine (but also other amino acids such as L-glutamine) are of great importance for therapeutic application (1). As a precursor of various active components, arginine has a direct influence on immune function, wound healing and on the formation of the gaseous neurotransmitter nitric oxide (NO), which in turn is endothetically active and regulates vascular tone (2). NO is an intra- and intercellular messenger substance with numerous physiological functions such as the induction of prostaglandin synthesis, the inhibition of leukocyte migration and platelet aggregation as well as hormone release and neurotransmission (1). L-arginine also forms the precursor of polyamines, which play an essential role in cell division and protein synthesis and therefore have a protein-anabolic effect. This effect is particularly evident in wound healing. Clinical studies have shown that the therapeutic use of arginine can promote the wound healing processes and thus shorten the healing phase (3). L-arginine is supported in these processes by the equally conditionally essential amino acid histidine, which plays a controlling role in inflammation (4).
 
Immunomodulating effect 

L-arginine also has immunomodulating properties through the formation of NO, ornithine and proline, which can be used therapeutically in inflammatory processes (5). Due to its stimulating effects on the cellular immune defence, arginine is successfully used together with other immunomodulating orthomolecular substances in recurrent diseases associated with a weakened immune response (6).
 
Arginine and arteriosclerosis prevention 
Arginine can be used preventively for atherosclerotic changes, as it can positively influence NO-mediated endothelial functions. It improves blood circulation, inhibits platelet aggregation and reduces lipid peroxidation (4).The positive effects of L-arginine in hypertension can also be explained by the increased NO synthesis. NO is also known as "endothelium-derived relaxing factor" because it triggers vasodilation in the vascular muscles. Arginine also appears to be able to influence increased blood pressure via renal mechanisms (7)(8).
 
Male fertility 

Another field of application is fertility disorders and erectile dysfunctions in men. Through improved NO synthesis and interaction with relevant enzymes, higher doses of L-arginine (up to 5 g per day) can significantly improve sexual function in men with erectile dysfunction (9)(10). Arginine also increases the number and motility of sperm (4).

Deficiency symptoms

Impact on Symptoms
Cardiovascular Increased cardiovascular risk, endothelial dysfunction
Immune system Increased susceptibility to infection, immunosuppression
Ammonia detoxification Disturbed urea excretion – Accumulation of ammonium in blood (hyperammonemia) 

Administration

General mode of administration
 
When		 L-arginine should be taken between meals to improve.
  Notes:
  • When taking L-arginine it is important to ensure a sufficient intake of antioxidants, as L-arginine as a precursor of NO can promote the development of nitrosative stress. Folic acid and vitamin B12 support the effect of L-arginine.
Side effects
Gastrointestinal complaints (diarrhea), headaches or increased irritability may occur at long term and high doses.
Contraindications
Recurrent herpes infections (latent herpes infections can be activated by reducing the L-lysine ratio), sepsis or severe inflammatory diseases (since additional nitrosative stress could occur here)

Interactions

Drug interactions
Hypotensive drugs (nitrates) A combined intake can improve the effectiveness of nitrates.

Phosphodiesterase inhibitors

(sildenafil, vardenafil)		 Regular intake of L-arginine improves the effect of NO donors.

Nutrient interactions
Antioxidants The combined intake with antioxidants such as vitamin C improves the bioavailability of NO and can counteract nitrosative stress.
Amino acids

Lysine may increase the effect of arginine by delaying arginine transport from blood to cells.
Lysine is said to inhibit the uptake of arginine into the virus-producing cells in herpes, as both amino acids use the same transport route.

Description and related substances

Description
Proteinogenic, conditionally essential, basic amino acid
Related substances
L-arginine

References

References

1) Hahn, A. et al. 2005. Ernährung. Physiologische Grundlagen, Prävention, Therapie.
2) Flynn, N. E. et al. 2002. The metabolic basis of arginine nutrition and pharmacotherapy. Biomed Pharmacother. 56(9):427-38.
3) Frias Soriano, L. et al. 2004. The effectiveness of oral nutritional supplementation in the healing of pressure ulcers. J Wound Care. 13(8):319-22.
4) Gröber, U. 2002. Orthomolekulare Medizin.
5) Satriano, J. 2004. Arginine pathways and the inflammatory response: interregulation of nitric oxide and polyamines. Amino Acids. 26(4):321-9.
6) Bansal, V. Ochoa, J. B. 2003. Arginine availability, arginase and the immune response. Curr Opin Clin Nutr Metab Care. 6(2):223-8.
7) Gouvea, S. A. et al. 2004. Activity of angiotensin-converting enzyme after treatment with L-Arginine in renovascular hypertension. Clin Exp Hypertens. 26(6):569-79.
8) Menzel, D. et al. 2016. L-Arginine and B vitamins improve endothelial function in subjects with mild to moderate blood pressure elevation. European Journal of Nutrition.
9) Chen, J. et al. 2006. Effect of oral administration of high dose nitric oxide donor L-arginine in men with organic erectile dysfunction. BJU Int. 83(3):269-73.
10) Gonzales-Cadavid, N. F., Rajfer, J. 2005. The pleiotropic effects of inducible nitric oxid synthase on the physiology and pathology of penile erection. Curr Pharm Des. 11(31):4041-6

References Interactions
Stargrove, M. B. et al. Herb, Nutrient and Drug Interactions: Clinical Implications and Therapeutic Strategies, 1. Auflage. St. Louis, Missouri: Elsevier Health Sciences, 2008.
Gröber, U. Mikronährstoffe: Metabolic Tuning –Prävention –Therapie, 3. Auflage. Stuttgart: WVG Wissenschaftliche Verlagsgesellschaft Stuttgart, 2011.
Gröber, U. Arzneimittel und Mikronährstoffe: Medikationsorientierte Supplementierung, 3. aktualisierte und erweiterte Auflage. Stuttgart: WVG Wissenschaftliche Verlagsgesellschaft Stuttgart, 2014.
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