Fresh install of El Capitan(10.11), tried to install Android Studio version 1.21.
Error:
Android Studio was unable to find a valid JVM. Please download it
For it to work on El Capitan (OSX 10.11) you need to install the Java Development Kit, not only Java VM
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
After installing JDK, Android Studio runs as expected!