Underarm sweating is a common problem - especially in the coming hot summer months. If you suffer from it, know that you're not alone - more than 200 million people around the globe, have this problem too. It can be quite embarrassing - constantly walking around with sweat spots on your armpits, and little drops of sweat forming on your forehead. In society today, people link sweating with not showering - so they will automatically assume that you have poor hygiene. That's not true of course.
As a result, you start avoiding social situations, which can lead to all kinds of problems - more than 5% of people report starting to develop social withdraw, or having issues with dealing with other people. That's why this is a problem you must fix.
The main function of sweating is removing excess heat from the body - that's why if you're overweight, you sweat more. You have a layer of fat underneath your skin, which makes it hard for your body to cool itself down.