The present invention relates to a substance delivery device comprising: (a) an electronic component, (b) a carrier component, and (c) a beneficial substance, the electronic component comprising: (i) a timer means for generating a carrier activation electrical signal that is time dependent; (ii) an electronic carrier activation means for releasing the beneficial substance in response to the carrier activation electrical signal; (iii) a power supply; and (iv) a substance delivery device activation means, for activating the device, having a construction such that once the substance delivery device is activated the electronic carrier activation means releases the beneficial substance in response to the carrier activation electrical signal. The substance delivery device is of particular value in the treatment of circadian, infradian, or ultradian cycle conditions.