Is 500mg daily L-Arginine supplement dangerous?
Feb 18, 2013
I recently purchased a 500mg daily L-Arginine supplement after hearing about it's benefits for working out and sexual performance. I currently take Reyataz/Truvada/Norvir and 1G Valacyclovir. I've read a few articles stating that L-Arginine is not recommended for those with herpes infection. Is 500mg a low enough dose to not worry about or should I just not take this supplement at all? Would the Valacyclovir counteract any effects the L-Arginine would have on promoting an outbreak?
Response from Mr. Vergel
Yes. You can go up to 1500 mg per day. Valacyclovir should protect you.
L-arginine is an amino acid with many functions in the body. One of these is its role in the production of nitric oxide which helps relax blood vessels. This relaxation is essential in the development of an erection. Drugs like Viagra increase the body's sensitivity to the natural rise in nitric oxide that occurs when we get sexually excited. Another approach might be to raise nitric oxide levels, which led to the idea of trying L-arginine.
Nitric oxide also helps the muscles grow by dilating blood vessels and increasing the amount of blood that flows through them to your muscles. It also improves circulation and allows glucose and amino acids to flow to the muscles more efficiently.
Oral arginine supplements may increase nitric oxide levels in the penis and elsewhere. The main data that generated some interest in the use of arginine for erectile dysfunction came from a small double-blind trial in which 50 men with erectile dysfunction received either 5 g of L-arginine or placebo daily for six weeks (NOTE: a capsule contains 500 mg, so 10 capsules a day!). More men in the treated group experienced improvement in sexual performance than in the placebo group. However, a double-blind crossover study of 32 men found no benefit with 1,500 mg of arginine given daily for 17 days. The significant difference in dose and shorter course of treatment may explain the discrepancy between these two trials.
L-arginine has been advertised as "natural Viagra" but there is little evidence that it works. Drugs based on raising nitric oxide levels in the penis have not worked out for pharmaceutical developers; the body seems to adjust to the higher levels and maintain the same level of response.
Arginine supplementation appears to work only in those whose erectile dysfunction is due to low nitric oxide levels. In other words, arginine would be unlikely to help those whose decreased libido is due to factors other than low NO levels. Remember, erectile dysfunction is a complex syndrome and may be due to many different factors, both chemical and psychological.
This site has a good summary of all studies:
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