Hi there. I think vigorous massaging may actually have been part of the problem. I was well aware that I had to massage vigorously in order to keep my scalp clean.
In the original thread I posted a link to a poster with a similar experience. Excessive Shedding: Could Co-Washing Be the Culprit? | hairscapades
Basically the writer has deducted that cowashing softened her follicles too much, leading to excessive shedding in the cleansing and detangling process which led to thinner hair.
There's a high chance this is what is happening to me.
I've also been doing some research on waxing preparation. Though I've never waxed my (body) hair before, many sites suggest exfoliating and moisturizing before waxing.
"Softer hair follicles release hair more easily; to make your waxing experience both pleasant and productive try exfoliating and then moisturizing prior to the event. First, exfoliate the area you want to remove hair from, then smooth on some type of non-comedogenic (non-clogging) moisturizer to soften hair follicles and the surrounding skin."
Discovery Health "What's the best way to prepare skin for waxing?"
SO, it seems to fit in with Hairscapade's theory. I did have A LOT of shedding during cowashing but I didn't really think anything of it. I stopped cowashing and started low-pooing, and on my third low-poo I already noticed a SIGNIFICANT reduction in shedding during cleansing.
So it's very possible that my follicles were softened too much, and then combined with my vigorous massages, it caused excess shedding thus thinning out my hair.