Hi Thao, thank you for reaching out. Hair shedding at the beginning of our Regrowth Treatment with 2% Minoxidil may happen for a small percentage of users and is nothing to be concerned about! It’s temporary, usually lasting from 2-8 weeks at most, and it actually indicates that the treatment is working as it's making room for new, thicker hair to grow in. Keep in mind once you’ve experienced initial results, you will continue to see improvement in your hair! If you would like to talk more about what to expect from our products, please contact Your Product Specialists are happy to support you Monday through Friday from 9am-9pm EST at (888)237-4131.