From Google: Presence in Nipples and Breasts The nipple and surrounding breast tissue contain a functional endocannabinoid system that plays a role in development and lactation:
Mammary Glands: CB1 and CB2 receptors are present in mammary epithelial cells (MECs) and the surrounding adipose (fat) tissue.
Lactation: In breastfeeding women, the endocannabinoid system helps regulate milk production and composition. CB1 receptors are particularly involved in the “suckling response” required for a newborn to nurse.
Sensory Nerves: Because the nipple is a highly innervated area, the CB1 receptors located on cutaneous sensory nerve fibers also play a role in pain and sensation in that specific region. National Institutes of Health (NIH) | (.gov) +4
This distribution explains why topical cannabinoid products (like CBD creams) can interact with receptors on the skin’s surface without needing to reach the internal organs. National Institutes of Health (NIH) | (.gov) +1