NMDA receptors when overstimulated cause nerve cell death and lessions in brain because of excitotoxicity- as a matter of fact in animal studies NMDA itself is used to induce brain lesions to order due to precisely this effect of killing brain cells. DAA is NMDA agonist so logically in sufficient amount can cause excitotoxicity/neurotoxicity.
DAA is present in small quantities endogenously, but that doesn't mean that exogenous DAA supplementation is safe- as we don't know at what dose exitotoxicity might become significant- as a matter of fact whole idea of DAA supplementation is to cause NMDA receptor stimulation at levels significantly higher than what would occur endogenously in order to try to stimulate the HPTA- which could obviously cause problems- we dont know for sure as not many studies were done on DAA- so in the end it comes to wheter one wants to give it a benefit of doubt.
IMO potential risk overweight benefits, and there are lot of reports of people having issues with DAA including myself- I never had any prolactin issues before I used DAA, it can also be coincidence- but there are other similar reports.