As effective as my 120 mg Zevia energy drinks, but more convenient and more cost effective. I am prone to bladder issues, and haven't had any using the melts. I crash hard after 8 hours, though. I've shared with 4 different friends/coworkers-- 3 also crash after about 8 hours, and the 4th only felt benefits for about an hour because "caffeine doesn't work" for her.