Matador trips has a good round-up on yoga retreats on Ko Pha Ngan -- it's good timing as a Travelfish researcher is heading there tomorrow to do a complete rewrite of our Ko Pha Ngan coverage -- I'm sure she'll be in need of a bit of yoga before the month is out...
So if yogo is your thang you'll want to give the story a read -- it is right here: Yoga on Ko Pha Ngan
They have a link for the YOGA RETREAT high up on the road between Had Salad and Mae Had - I called in a fortnight back to hire a mountain bike they were offering - a whole bunch of sleek looking types hanging around ready to start an instructors' course - they looked so healthy I almost signed up.
My Had Sadet-Samui ferry called in at Had Thian, home of The Sanctuary and others. A Brit girl on the ferry pointed left: "Detox there", right: "Retox there!" Sounds like my sort of place.
I've done the seven day fast at Sanctuary three or four times now -- first time was the best. There's a story about it here: http://www.travelfish.org/feature/5
Sanctuary the resort is pretty cliquey, but the Wellness Centre (that does the fasting courses) is spot on. They used to have a masseuse there from Pattani who gave the best massages I've ever had.