Advise not to take double. Take single first because if single works, double dose does not make it more effective. Furthermore, if you dont't conceive on a few months with single dose, doc may then choose to put you on double. Too much clomid can increase risk of ovarian cancer so dont't double your risk now when there is no need. I was on single dose clomid for many months and responded well, doc upped dosage only after about 8 cycles and after that I had to stop clomid because prolonged usage is no good. So dont't decrease your own chances - better to take for a longer time if you dont't conceive straightaway, than to shorten your possible clomid time when there is not necessarily increased benefit. Hope you know what I'm trying to say and that this helps.