Is it okay to use the shampoo?

For the last four months, I’ve been honored to be a guest in friends’ homes every shabbos—Friday afternoon through Saturday night. Sometimes I remember to bring my own shampoo, and sometimes I need to depend on the kindness of my hosts to avoid an unhealthy mix of dandruff and oily hair on shabbos. Is it okay to use my hosts’ shampoo? What if the bathroom has a Shampoo Planet collection? That means enough hair treatment product to destroy the ozone layer. Oh, the plethora of options! Someone admonished me and strongly suggested using soap is fine, but I should bring my own shampoo. Other costs associated with hosting me: laundry for the towel and sheets that I soil for one night’s rest (plus nap). Any thoughts?