It's the disorder no one wants to talk about, yet according to the Journal of the American Medical Association, 43% of women and 31% of men suffer from sexual dysfunction.1 Sexual dysfunction is broadly defined as the inability to fully enjoy sexual intercourse. Women generally experience it as a loss of libido (sexual drive) and/or the inability or difficulty in achieving an orgasm. Men experience it as impotence, known technically as erectile dysfunction.
Based on hundreds of studies, L-arginine, an essential amino acid and one of the building blocks of proteins in the body, has become known as a safe and effective prosexual nutrient for men and women.
L-Arginine is a precursor of nitric oxide (NO) in the human body. In the 1990s, scientists discovered that not only is NO an essential compound that helps blood circulation, but it is important to normal sexual function in both men and women. Without arginine there would be no NO, and without NO, men would not be able to have erections.
How L-Arginine works
Insufficient blood flow is a major cause of incomplete erection in men.
L-Arginine has been shown to improve blood flow to the genital area by dilating blood vessels and helping the penis to enlarge to its full capacity, thus increasing the size, hardness, and frequency of erections.
Nutritional expert, Dr. Jonathan Wright, explains the mechanism in men: "Molecules of NO are generated when an enzyme called NO synthase (NOS)—which is abundant in the nerve and muscle cells in and around the penis—strips away a nitrogen atom (N) from a passing molecule of the amino acid L-Arginine … and combines it with an atom of oxygen (O)." 2
In other words, in order to produce nitric oxide in the body, a nitrogen atom must combine with an oxygen molecule in the blood. The enzyme called nitric oxide synthase controls this reaction.
L-Arginine has a similar effect in women
Higher blood flow makes clitoral and vaginal tissues more sensitive and responsive to sexual stimulation and helps increase the possibility of reaching orgasm. Although there haven't been nearly as many studies done on arginine supplementation in women as in men, one study found that postmenopausal women who took a supplement including L-Arginine experienced heightened sexual response.3
Another study involving 77 women of all ages found that after four weeks, 73.5% of the women who took a supplement including L-Arginine experienced greater sexual satisfaction, including heightened desire and clitoral sensation, frequency of intercourse and orgasm, and less vaginal dryness.4
Stronger libido ... greater endurance
Both men and women report that L-Arginine seems to increase their libido or desire for sex, and some also report that L-Arginine gives them greater endurance and stronger, more powerful orgasms. Reports also suggest that L-Arginine supplements can improve fertility in men who have low sperm counts or poor sperm motility (activity).
The powerful effect of L-Arginine was illustrated in a double-blind, placebo-controlled study published in the British Journal of Urology International in which researchers evaluated the nitric oxide levels of 50 men with erectile dysfunction. The men were given either L-Arginine or a placebo for six weeks. Nine of the 29 men (31%) given L-Arginine reported a significant improvement in their sexual performance. These nine men had low nitric oxide levels at the start of the trial, but their levels doubled by the end of the study.5
It is important to note, however, that erectile dysfunction can be caused by a variety of factors, including aging, diabetes and other endocrine disorders. L-Arginine may be effective only in those men whose erectile dysfunction is due to low levels of nitric oxide. In fact, in one study in which the participants suffered from impotence for a variety of reasons, L-Arginine was found to be effective in only 17% of the patients.6 However, optimal nitric oxide production will ensure optimum erectile function, and for many people with sexual dysfunction not related to an underlying disease, arginine supplements will ensure adequate nitric oxide levels.
Studies done on animals provide some evidence for effectiveness as well. In a laboratory study, two groups of rats were given free access to L-Arginine which was dissolved in their drinking water. Both groups had greater serum and penile concentrations of arginine, and exhibited a significant increase in intra-penile pressure or "hardness."
Serum and penile tissue levels of L-Arginine in the treated rats were increased by 64 - 148% compared to control animals. The penile nitric oxide levels also increased nearly 100% in the L-Arginine treated groups compared to the control groups. The researchers concluded that these data support the use of dietary supplements for treatment of erectile dysfunction.7
The positive benefits of arginine go beyond sexual enhancement
This remarkable amino acid helps build muscle mass, enhance immune function, improve blood pressure, increase memory, and speed wound healing.8910 Arginine-derived nitric oxide has also been found to play a supporting role in the cardiovascular, immune, and nervous systems and has been validated by hundreds of studies.
L-Arginine is essential to several systems in the body. Among its many roles, L-Arginine:
- Is a precursor of nitric oxide (NO)
- Promotes circulation resulting in improved blood flow
- Stimulates the release of growth hormone
- Improves immune function
- Reduces healing time of injuries
- Plays a role in the formation of bone and tendons
- Increases muscle mass, while reducing body fat
- Supports male fertility, improving sperm production and motility
- Reduces risk of blood clots and stroke1112
- Supports normal blood pressure13
- Improves vascular function for patients with angina14
- Helps recovery after heart attack15
- Helps prevent and treat cardiovascular disease16
- Helps reduce growth of cancerous tumors17
Timing and contraindications
L-Arginine users say they can achieve a prosexual effect by taking it 45 minutes before sex. There are few reported side effects. The most notable is:
- People with herpes - L-Arginine may increase the severity of outbreaks, but some reports indicate that it may also enhance your immune function enough so you are less likely to get herpes outbreaks.
L-Arginine is an excellent supplement for anyone wanting to increase his or her sexual arousal, improve performance, and overall health. The huge advantage this natural and safe supplement has over Viagra is that both men and women can take it, it's considerably less expensive (Viagra costs as much as $10 a pill!), and it's been proven to work in numerous double-blind studies.
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This article is not intended to diagnose, treat, cure, or prevent any disease. Always consult with a physician before embarking on a dietary supplement program.
Laumann et al. Sexual Dysfunction in the United States: Prevalence and Predictors. JAMA.October 6, 1999; 281: 537-544.
Wright, J, M.D. and Lenard L PhD, Maximize Your Vitality & Potency For Men Over 40, Smart Publications, Petaluma, CA, 1999, p. 225.
Meston CM, Worcel M. The effects of yohimbine plus L-arginine glutamate on sexual arousal in postmenopausal women with sexual arousal disorder. Arch Sex Behav. 2002 Aug; 31(4): 323-32.
Ito TY, Trant AS, Polan ML. A double-blind placebo-controlled study of ArginMax, a nutritional supplement for enhancement of female sexual function. J Sex Marital Ther. 2001 Oct-Dec; 27(5): 541-9.
Chen, J. et al. (1999). "Effect of oral administration of high-dose nitric oxide donor L-arginine in men with organic erectile dysfunction: Results of a double-blind, randomized, placebo-controlled study." British Journal of Urology International; 83(3): 269-73.
Klotz T, Mathers MJ, Braun M, Bloch W, Engelmann U. Effectiveness of oral L-arginine in first-line treatment of erectile dysfunction in a controlled crossover study. Urol Int. 1999; 63(4): 220-3.
Moody JA, Vernet D, Laidlaw S, Rajfer J, Gonzalez-Cadavid NF. Effects of long-term oral administration of L-arginine on the rat erectile response. J Urol. 1997 Sep; 158(3 Pt 1): 942-7.
Cooper, M.D., M.P.H., Kenneth H., Advanced Nutritional Therapies (Nashville: 1996, Thomas Nelson, Inc. Publishers), pp 87-88, 93, 94. ISBN 0-7852-7302-6.
Hendler, M.D., Ph.D., Sheldon Saul, The Doctor's Vitamin and Mineral Encyclopedia (New York: 1990, Fireside), pp 209-215. ISBN 0-671-66784-X.
Mindell, Ph.D., Earl, Earl Mindell's Anti-Aging Bible (New York: 1996, Fireside), pp 23-24. ISBN 0-684-81106-5.
Broeders MA, Tangelder GJ, Slaaf DW, Reneman RS, oude Egbrink MG. Hypercholesterolemia enhances thromboembolism in arterioles but not venules: complete reversal by L-arginine.Arterioscler Thromb Vasc Biol. 2002 Apr 1; 22(4): 680-5.
Lin PH, Johnson CK, Pullium JK, Bush RL, Conklin BS, Chen C, Lumsden AB.L-arginine improves endothelial vasoreactivity and reduces thrombogenicity after thrombolysis in experimental deep venous thrombosis. J Vasc Surg. 2003 Dec; 38(6): 1396-403.
Michelakis ED, McMurtry MS, Sonnenberg B, Archer SL. The NO - K+ channel axis in pulmonary arterial hypertension. Activation by experimental oral therapies. Adv Exp Med Biol. 2003; 543: 293-322.
Maxwell AJ, Zapien MP, Pearce GL, MacCallum G, Stone PH Randomized trial of a medical food for the dietary management of chronic, stable angina. J Am Coll Cardiol. 2002 Jan 2; 39(1): 37-45.
Amrani M, Gray CC, Smolenski RT, Goodwin AT, London A, Yacoub MH.The effect of L-arginine on myocardial recovery after cardioplegic arrest and ischemia under moderate and deep hypothermia. Circulation. 1997 Nov 4; 96(9 Suppl): II-274-9.
Chagan L, Ioselovich A, Asherova L, Cheng JW. Use of alternative pharmacotherapy in management of cardiovascular diseases. Am J Manag Care. 2002 Mar; 8(3): 270-85; quiz 286-8.
Novaes MR, Lima LA. [Effects of dietetic supplementation with L-arginine in cancer patients. A review of the literature] [Article in Portuguese] Arch Latinoam Nutr. 1999 Dec; 49(4): 301-8.