Is there a minium suggested fasting time?

I'm just in day 2 of my first Master-Cleanse and I was initially planning on 5 days... after having read some accounts online it sounds like I may /need/ to go longer.

I'm concerned that 5 days may not be long enough to complete a really essential portion of the fast.

Can anyone shed light on my concern?

Thanks in advance.

Regards,
Mrlynn Tweet