Hmmm...I have used this before. I felt so weird putting animal placenta on my head, but at the time, my hair was very damaged and I was doing all I could not to have it break off more. I didn't really notice a difference, but again, my hair was a little past saving at the time.
Henna actually does act as a protein treatment, I have read. I'm not sure what the placenta is supposed to do. I would treat it as a PT and follow it up with a conditioner. On a side note, I love how it is super cheap.
If anything, I feel as if it's a very mild "strengthening" treatment. I've used it many times, never following up with a moisture conditioner and my hair was fine. But I will say, that may be because my hair loves protein. I've stopped using it as frequently though, doesn't seem to be as effective as before. But since it's so cheap, I keep it around.