It was definitely true that my hair was less oily than I expected. There were many days when each hair stood alone, unclumped from the others, and I thought I was near to fluffy kittenhood. But then the next day I'd forget to rinse it or something and I'd be a greasemop.
Also, and this may have been psychosomatic, I felt like the greasiness was starting to migrate down my head. Like maybe the hair was leaving oily trails on my forehead, on the tops of my ears, etc.
Experiment terminated after two weeks.