Hello Matt,
Someone already listed Sabre brand pepper spray. It works pretty well, and I used it personally and been sprayed with it in training. The effects lasted for several hours. There's a
LE and non-law enforcement versions. As someone already stated oc spray doesn't work 100%, but it's an option and it can be more difficult for an assailant to attack you if they can't see. One last thing, when deployed up close it usually gets on you too.
If by LA you mean Los Angeles, most Law Enforcement Academies offer courses to non-sworn individuals. Ben Clark Training Center or Riverside County Sheriff's Department Academy offers pepper spray training.
Avoiding a fight is usually the best option, but sometimes you have to deal with a problem rather than avoid it.