edited.
I no longer believe propecia can maintain any minoxidil hair.
minoxidil is strictly additive and does not stop balding. It might protect blood vessels a bit, but does not fight balding at all.
SODs actually repair hair, I think, so propecia can maintain growth.
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original post
rogain can make intermediate hairs look terminal, when their anagen phase has just been lengthened. I'm not saying propecia will keep the anagen phase lengthened like that, so getting off rogaine can cause hairs to grow to shorter lengths if they were not fully terminal to begin with. Also, propecia is better at maintaining terminal hairs than intermediate hairs. I'm saying that if you fully repair all hairs with topicals so that they accually are terminal, and minoxidil is lengthening their anagen phase from 2 years to 4 years and not 2 months to 1 year so that they just look terminal, propecia can maintain the hair. i am not saying that you can keep all the density and length of rogaines magnification just by using propecia. i never meant that.
people respond better to propecia if they have more hair when they start. If everyone just maintained their hair, that claim would not be valid, since thin people would have the same results as nearly thick haired people. it follows that time and genetics are not the only factors determining whether a follicle will respond well to propecia. If they were the only factors, then men who started 5 years later would catch up to genetically similar men who started early, which does not happen.
therefore, if you regrow you hair with topicals, by whatever mechanism, those follicles will then respond to propecia better than they would have in their miniturized state. But it has to be actual regrowth, and not just thin hairs getting longer from staying in anagen longer.
i believe that if one guy uses propecia from day one for 5 years, and his identical twin starts 3 years after him and is balder then and uses super topicals to regrow all his hair and pass his brother (who is thinning a little like in my avator) and reach the state where his brother at his best, and then gets off the topicals and uses propecia only, he will loose hair from there faster than his brother, and will slowly get down to exactly where his brother is at year 5 or 6 or later, however long it takes them to converge. he will not fall down to as far as he would have been had he just used propecia from year 3 onwards and never used the topicals.