Well 5 are mine, one of the housemates is a girl, and the other one also has a girlfriend who stays there a lot. So most of the bottles are for girls 
Well, first you said you didn't have space for your stuff, now you change your story... women, no way to please them.
Which reminds me. Since I have memory, my bathroom has never been stuffed with assorted bottles and products. One shampoo, one soap, one toothbrush. Simple.
It was always awkward for me when I had to take a shower in someone else's house, because they had multiplicity of bottles, soap bars, sponges, luffas, volcanic rocks, creams, etc. It's crazy. It feels too crowded.
Nowadays, I do have at least two bottles of shampoo. I realize it helps to have two different brands, because sometimes one stops working, like my hair develops immunity to it. Using one during one week and then switching to the other is better.