Rosemary rinse to thicken hair?

[Shatam1]

I add rosemary essential oil to my henna along with other oils every two weeks but I don't know if that counts

[TheHowlingWolf]

Tomorrow is wash day for me & I might try this rosemary rinse! I also might add lavender & catnip?

[Melisandre]

I've used rosemary as a rinse for the last month about 4 times, and it made my hair feel thicker, more voluminous. My scalp loves it, but I stopped using it because it also made my henna darker which sucks because I love my henna colour as it is

[White]

I've been using it along with some other herbs (sage, nettle, lavander) as my final rinse, I make a very strong brew and I don't wash it out, just leave it there and let my hair dry. There is definitely less shedding, plus hair smells like heaven. It doesn't help me with my growth, my hair grows at the same rate as before, no improvement there. But less shedding no doubt.
I don't know if it darkens hair either, I'm dyeing mine in black so I cannot see.