Have little to share about what 5mg - 15mg does overtime as I can not subjectively note any positives which I can attribute to it. Above 20mg on most days I tend to erect but thats really dependent on my estroidal levels. In theory low dosage should be helping work around prostate enlargement, give you increased pulmonary blood flow (better workouts) and a couple more positives I do not recall. So if you are having to get up and piss many times during the night because of enlarged prostrate I believe the studies show low dose 5mg may be helpful. Some guys do use it preworkout, but I have no idea what dose they require.
It is very expensive in most countries making it prohibitive without insurance. Some guys on here sell it for about $1+ a 20mg dose. By all means, split tabs or dropper and get the low dose close rather then paying for 5mg tabs.
IPG