Also, a supplement being labled "500 micrograms" has no requirement to be correct. The FDA has handwaved away the entire industry, and broadly there is zero qua

Also, a supplement being labled "500 micrograms" has no requirement to be correct. The FDA has handwaved away the entire industry, and broadly there is zero quality control for actual active ingredients. Many supplements will claim that they've been tested, but there's no legal requirement to do so, the labs are usually owned by supplement makers, and there's no penalty for lying about any testing as fraudulent marketing claims largely go unpunished because the US judicial branch chooses to interpret the law stupidly conservatively