Soundproof thin interior wall

[ptlf]

Is it possible to use "soundproofing panels" available for purchase at car accessory stores in an interior wall? The wall against the bathroom only has 34mm studs and I haven't found regular sound insulation that thin. Now I'm wondering if these panels can be built in, I think they are available in 20mm thickness but what are they made of/treated with, could it be harmful to build in such panels, odor etc. Anyone with experience with these panels?

 

[Elvis69]

If you can't get hold of insulation, you can always complement the wall with one or more layers of gypsum (if there is space). This can make quite a big difference if the wall itself is uninsulated.