The expiry date is mentioned on each blister. It is different for different batches. The shelf life is 2 years from the date of manufacture and would differ from batch to batch depending on when they were manufactured.
Regarding the effect: I do notice an increase in bloodflow and a better
stamina using the pills (I use 50mg). A side-effect I have noticed is that
my nose clogs up so I seem like I have a cold for an hour or so after taking
one pill. No other side-effects than that.