60 days is on the very very low end...
Usually you would run it for minimum 16 weeks to notice any real benefits but to truly see it shine ? 6months plus.
Also ask your friend how he has been storing it, what expiration date, what brand etc.
If it hasn't been stored properly(its very sensitive) it will be degraded and sometimes even totally ruined.
If you have the cash to spare and wanna dabble it in, for a first run? I would run 3iu for 100 days. You wont see any amazing benefits far as growing but you'll get better sleep, better skin, increased fat loss, bit faster recovery and overall well being.
Its also a safe dose where your organs wont grow and shit.
About your 5 vs 10 iu comment, it will ALWAYS be better to run lower doses for a prolonged time in every aspect. There's "advanced" exception to this rule but lets keep it simple
What megatron says is very true though...fuckton of fake GH around, even more mishandled.