Six months? Still quite young, I would say. Now, I can't vouch for the
medicinal strength of the compounds, but something preserved in alcohol will stay....well, a long time.
As for the flavor--it only gets better! The old Europeans would put keep their tinctures for decades, but some of it was beyond medicinal, like, a snake or a toad or something in their eau-de-vie. Usually it was more like cherries or herbs. That is actually the point of aged whiskey; instead of an herbal tincture it's a charred oak tincture and it just gets better and better. And of
course there is no end to the human-body-preserved-in-whiskey-barrel stories.
I usually make too much tincture, so I end up blending many of them, adding some maple syrup and letting them sit 3 months AT LEAST before enjoying with guests as liqueur.
The same goes for vinegar. The flavor gets better with time, but perhaps the medicinal compounds are not as active?