Kylie Jenner -- Butt Cream Company ... Back Off, We Didn't Pay Kylie

PureLeef, the body plumping cream company that got a huge lift from Kylie Jenner, claims she did it all on her own, for free.

Kylie, who turns 18 August 10, got tons of backlash for what some say is an inappropriate Instagram photo promoting the company’s butt enhancement and breast plumping creams.

A lot of people are calling BS, saying she got her butt and boobs from surgical knives, not cream.

But the company insists the endorsement was unsolicited. They say they didn't pay Kylie, but they don't say if any money went to anyone else Kardashian related.

It's interesting ... the company is big on parental controls, saying they urge parents to get involved if the user is under 18. It's unclear if this is an endorsement or a shot at Kris.

As for the cream, PureLeef boasts, “We feel our way is much safer and less final than surgery or black market 'butt injections' all while producing real results.”