Systems and methods for regulating transmit power in a mobile station to comply with SAR limits are disclosed. A mobile station may include a processor, transmitter, and proximity sensor. The transmitter is configured to operate at a transmit power controlled by a first transmit power limit. The proximity sensor identifies how close the mobile station is to a human head. A transmit power regulator, implemented on the processor, determines the cumulative energy radiated by the transmitter over a specified number of frames. If the cumulative energy exceeds an energy limit based on a SAR limit, and the proximity sensor indicates that the mobile station is close to a human head, the transmit power regulator may decrease the transmit power limit of the transmitter.