Alot of people i know have struggled from dark under arms, so i found this article on line and used myself as a guinea pig using the lemons and one week or so of using them there is visible improvement. Having dark underarms is not a disease or a medical condition. Dark underarms can be defined as the dark coloration of skin in the underarms region in comparison with the rest of the body. It is something like sun tan that happens when skin gets exposed to ultraviolet rays for longer period of time. Some of the main causes of dark underarms are shaving, regular use of hair removing creams, excessive sweating, poor ventilation of underarms, accumulation of dead cells, use of alcohol-based deodorants and antiperspirants, excessive smoking, and health problems like obesity or diabetes. If you have dark underarms, there is nothing to worry about as you can easily get rid of them by following simple home remedies. These remedies are safe, effective, natural and affordable and that too without any side effects. However, at times dark underarms may also be as a result of a medical condition that is known as acanthosis nigricans. If the reason is acanthosis nigricans then you must consult a doctor as home remedies may not help with dark underarms and you may need proper treatment.