20 = 667
Although the FDA typically agrees with the committee, the agency would still have to finalize new regulations, which could "take months or years to draft," according to the A.P
It only becomes toxic when metabolized into NAPQI
In vitro studies further revealed that schisandrin B suppressed oxidative stress and inflammation in BV2 microglia and PC12 cells [63, 64] and protected against microglial-mediated inflammatory damage in microglianeuron cocultures by downregulating NADPH oxidase and other mediators, such as NO, TNF-, PGE-2, IL-1 and IL-6 [37]
It's a relatively high amount for a supplement to have, but it shouldn't be a problem for most people since the maximum per-day allowance for adults is 400mcg.34 That said, you may want to avoid Doctor's Best Glutathione + Milk Thistle if you take another supplement that includes selenium or eat a lot of selenium-rich foods (e.g., Brazil nuts, tuna)