30 days worth of parasite cleansing is needed to kill parasites in all stages of their life cycles. 21 days will do it - but the extra 9 days ensures a thorough cleanse. It saturates the blood, organs and muscles.
HUMAWORM is a strong formula - if less potent formulas were taken over a much longer period of time - resistance can occur - whereas, if a much stronger formula were taken over a less period of time - it will not kill and remove everything.
The bacteria and viral formulas are 15 days - this timing is so that resistance of the bacteris and viruses won't occur.
The 30 day protocol was handed down to me from my grandmother who learned it from her mother and so forth. Over the years we have been told by different experts that the the HUMAWORM protocol is fine. I just judge it by the results we get.