Definition: In this task, you're given reviews from Amazon's products. Your task is to generate the Summary of the review.
Input: This gel used to work. But the supplier seemed to change the formulation which caused the gel to work the opposite. It causes so much itching and turns the underarms dark. I wish they didn't change the product because it used to work so well to whiten the underarms.

This gel used to work. But the supplier seemed ...