Water fasting alone - Possible?

Hi guys,

I am new to this forum and I am thinking of starting a Water Fast alone (i.e. without physician's supervision) with a goal of 21 days. Would this be possible?

I have been doing intermittent fasting 2-3 days a week (non-consecutive) since January. I generally find them okay apart from occasions of insomnia.

The thing that I am unsure about water only fasting, unlike IF, is that there are little evidence or studies about the topic. This made me wonder about the safety boundaries, which were things like whether there was a point （apart from the return of hunger) that other fasters feel they are breaching into the "danger zone" and therefore had to stop?

Also, I have been reading different thing about the recovery period - ranging form 1 day recovery for every 5 days of fasting to recovery time = fasting time. I was just wondering what other fasters did and how they found it.

Thank you!!