Agmatine is derived from arginine, a primary amino acid. Agmatine acts as a neurotransmitter to induce production of growth hormone, nitric oxide, creatine and protein; decrease blood glucose levels; and aid in the removal of nitrogen waste products from the body. A report in the Proceedings of the National Academy of Sciences indicates that agmatine is capable of preventing and treating spinal cord injuries, inflammation and neuropathy; however, every exogenous supplement has some side effects associated with use or overuse.

Gastrointestinal Disturbances

The patent for agmatine-containing products indicates that only three of the trial participants reported gastrointestinal disruptions at low doses. Those disruptions included diarrhea, nausea and vomiting that began after two days of taking agmatine and continued until treatment ceased. Only one of the people experiencing these problems dropped out of the clinical trial because of the discomfort caused by agmatine.

Lower Pain Threshold

A study published in the "European Journal of Pharmacology" indicated that large doses of agmatine actually lowered the overall pain threshold even though low doses improved overall response to chronic pain. Rats were utilized to determine if agmatine was capable of improving the response to acute pain from a new injury at low doses. Unfortunately, agmatine appears to have little ability to limit acute pain, even though the same dose appeared to stop pain perception from old injuries.

Neurotoxicity

Agmatine is a low-affinity N-methyl-D-aspartate, or NMDA, antagonist; thus, the threat of neurotoxicity is possible although extremely unlikely. According to agmatine’s patent information, it has a 500,000-times lower affinity for NMDA receptors than typical antagonists. A report in “Science” indicates that NMDA antagonists may produce hallucinations, and they have been shown to cause morphological changes in the cerebral cortex of rats.