fingers crossed its the common 25mg/ml seen on liquids... for 500 of test I imagine you could be safe as low as 6.25mg/day aka 1/4ml, unless you have abnormal aromatase conversions naturally then may need to go 12.5mg/day aka 1/2ml but generally speaking you'd be surprised how effective 6.25mg/day is after going about 1-2 weeks consistent... due to short halflife I would always recommend sticking the ED dosing too and not EOD, but frankly its what ever you experiment with that your body responds best to..