A most interesting signature.
My personal feeling is that this is highly probable to be not by the hand of JJ. It's very similar though but the angle for one is wrong in my humble opinion. So I have some concerns.
Her signature is one that can be very easily copied/faked which is problematic. Whilst it maybe genuine as suggested by another member I would tread very carefully with this one. One would need to carefully examine the signature and promo photo along with obtaining credible provenance.
Just my thoughts.
The background posted on it by owner (presuming they own it), it was sent to a music magazine by Grossman Glotzer to promote Janis circa 1968. They had also seen similar one on PSA page, perhaps the same one BallroomDays posted if that was the source?
The image I posted is from RR Auction. Yes, it’s the same one from the PSA page.
Do you have a picture of the reverse?
It's already framed they said.
What are they asking for it?
They are not selling yet, looking to authenticate first, going to Houston so sounds like TriStar to me. I do not know them myself, was only getting opinions.