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TECHNICAL
RESEARCH
Side effects & adverse reactions
Published studies have indicated few serious problems related to taking L-arginine
supplements. A few cautions about this amino acid are worth considering, however.
L-arginine may be problematic for some people with serious herpes infections. Once they
enter the body, herpes viruses take up residence and generally remain dormant until
stimulated into replication by factors such as stress or sunlight. Although L-arginine
does nothing to initiate a herpes attack, once such an attack is stimulated, the virus may
utilize the extra arginine molecules to enhance its replication, making the attack worse
than it might have been otherwise [Griffith, 1981].
L-arginine should not be used if you have ocular or brain herpes. If you have any other
problems with herpes, you should consult your physician before taking L-arginine [Pearson,
1986].
If you are diabetic or borderline diabetic, you should not use L-arginine or any
GH-releaser, because it may make the disease worse by raising blood sugar levels. A few
anecdotal reports also suggest that L-arginine may temporarily worsen arthritis in rare
instances [Pearson, 1986]. GH-releasers do not produce cancer and have actually been shown
to reduce the incidence of cancer in experimental animals.
L-arginine or any other GH-releaser because of the remote chance that the added GH may
promote the growth of a pre-existing cancer.
Overall, it appears that high doses of L-arginine do not seem to cause serious problems.
In the study of surgical healing mentioned earlier, "industrial strength" doses
of arginine were given to very sick and debilitated people with no toxic effects [Daly,
1988]. Long-term use of high doses has not been studied, however.
As a final note, NO produced from L-arginine is a free radical. While free radicals are
usually considered to be destructive and dangerous molecules that can alter DNA and wreak
other cellular havoc in the body (antioxidant nutrients like vitamins C, E and
beta-carotene are free radical scavengers), NO does not fit the standard free radical
profile in some important ways. It has a very short life span (only a few seconds), which
means it is neither as promiscuous nor as reactive as most other free radicals. In
addition, because free radicals can only be destroyed by reacting with other free
radicals, some scientists think that NO may be crucial for controlling other free
radicals, since it reacts with them and neutralizes them before they can do any harm. In
short, NO does not seem to have the destructive potential of typical free radical
molecules, so you need not worry about creating extra free radicals when you take
L-arginine.