How are hormones different from neurotransmitters and pheromones?

Hormones, neurotransmitters, and pheromones are all chemical messengers, but they differ significantly in their targets, transport methods, and biological roles.

Hormones

Hormones are chemical integrators secreted by glands, nerves, or tissues that regulate physiological activities and maintain homeostasis. They typically travel through the circulatory system to reach target cells far from their site of release, though some act locally via diffusion. They bind to specific receptors on or within cells to elicit responses.213

Neurotransmitters

Unlike hormones, which coordinate broad physiological functions, neurotransmitters are specialized for rapid communication within the nervous system. They are released by axons to act on adjacent cells, such as muscles or other neurons, facilitating quick actions like movement.23

Pheromones

While hormones and neurotransmitters function within an individual, pheromones are secreted to the outside of an organism to communicate with other individuals of the same species. They are released into the environment to elicit specific behavioral or developmental responses, such as sexual attraction, aggregation, or danger signaling.45