Peak baby or any formula won't do the magic. Firstly, introduce complementary food to her since she is 6month, experiment different rich food, potatoes, carrot, pear avocados, egg yolk, boneless Titus, powdered rice, varieties of cereals etc. My 10mnth has been on peakbaby since scarcity of thrive formula ( at 6mnth), yet her weight at 9mnth was 7.8kg. Personally am not bothered with weight provided a baby is healthy and attaining her developmental milestone (which my supersede sef)