Used Oral Min for 8 months last year at 5mg. Good density gains, not much frontal regrowth. Stopped because I was getting too hairy and felt some slight stings in my chest (nothing major, but they never ocurred once I stopped the drug)
Tried resuming it's use this year starting at 1.5-2.5mg, but somehow I've become much more sensitive to the drug. Had persistent angina for 3 days after 2 weeks of initiation and called it a day (it also ceased to happen once I discontinued the drug, was quite the experience)
I would advise you to never to go past 5mg. If you respond well and tolerate it at this dosage, great, if not, drop it. A lot of broscience says it's relatively safe because it's used to treat BP at 40mg-100mg but that's FALSE, those dosages are mostly common on cardiac urgencies. Most studies – and believe me, I've read them all – for daily BP control have patients taking 5mg-40mg of the drug, with an average dose of 10-15mg (most of the authors also strongly recommend supplementing b-blockers and diuretics). In some drugs, a 2.5mg increase can be quite a huge jump - ex.: 0.5mg vs 3mg of dutasteride