I NEVER lend money at the poker table, EVER...one of two things can happen, both bad:
1. Player loses money and now you have to chase him down for money. If it's a friend/social acquaintance, then, it's awkward and uncomfortable. Plus, of course, sometimes they flake completely. If it's a stranger, good luck!
2. The Player wins, and takes money from your stack. This has happened a lot to me early in my poker playing days (mostly college/post college)...we weren't playing for much money, and it was all limit (NL was not played much in the 80s!).
The only good result is that the game keeps going...but in my world, we're degenerate enough to play three handed, or even heads up, so that really isn't an issue