It’s a given that using a VPN can decrease game performance due to the additional processing and encapsulation of the traffic. I suppose these issues do not happen without the VPN?

Network restrictions are there for a reason, but why don’t you run a traceroute and find out why?

Try using a gaming VPN in case you are having troubles of ping in LoL.. You see gaming VPNs are dedicated applications that enhance your connection with the game server unlike normal VPNs that are used for online anonymity and security. Although there might be other reasons that I might not know of but for me VPN is just about that.
I am a Dota 2 player and am currently using Kill Ping for reduce my ping in the game. Normally it was above 160ms if I played in EU servers. Now its less than 90ms and thats a huge plus for me.
The application has a trial so you can try it to see if it works for you or not.

@omaritani1993 , just because the VPN connection you’re using doesn’t affect the ping on your other games, doesn’t mean it won’t affect the ping for every game. You’ll need to figure out the region in which your client in connecting to, and try to find a VPN server as close to the region you possibly can.

http://www.wtfast.com/ claims to speed up your gaming, I’ve tried it and didn’t really do much for me, I guess because I have 1GB fibre connection and the game server is relatively close. On slower connections it may have a bigger impact.