Cotbed mattress toppers

[Quacks2020]

Hi,
Just looking for some advise on mattress toppers. The reason I'm looking is for comfort. Bit more cushiony than just a sheet.
Question is, are they safe to use? Would anyone actually recommend them or best just to stick to a sheet?.
My DD is 13 month old. Always an empty crib.
Thanks

I've actually been wondering this too. My DS has a cot mattress with a mattress protector and then a sheet, but because of the (ridiculous) position he sleeps in, he puts all his weight on his knees and wakes up with red marks on them which makes me sad. A wondered if a mattress topper would make it more comfortable and stop the marks, but didn't know if they were safe/advised either...

Sometimes I just feel the mattress and obviously with no pillow I just think it's not the most comfortable!!.

Then its finding one that is safe to use. I've tried googling it but theres no clear advise about it.
I have a breathable mattress and wondering if there is a branded mattress topper which is the same