this a faster oh-my-zsh plugin manager than zsh itself?

I'm aiming to improve zsh startup time, I'm using oh-my-zsh at the moment and use a lot of plugins from it.

I saw https://github.com/tarjoilija/zgen#oh-my-zsh the guide on using oh-my-zsh plugins with this, but also saw that I should zgen oh-my-zsh before loading plugins,

won't this incur the whole startup time of oh-my-zsh then?