Some of the lesser-known forms of testosterone therapy (TT) are those that utilize the skin. Transdermal, or topical, methods of treatment utilize the science of the skin. Human skin is the largest organ of the body, creating a large semi-permeable membrane. Semi-permeable membranes are unique in that they allow certain substances to pass through them. Human skin can be used to administer specific types of medications that are easily absorbable, like certain forms testosterone therapy.
Skin patches are a form of TT that works in the same way a birth control patch does. That is, the patch contains small amounts of hormones that are capable of passing through the skin into the bloodstream. Skin patches must be replaced every 24 hours, between the hours of 8 p.m. and 12. p.m., to maintain a steady, predictable application of hormones. Users must apply their patch to their upper arms, thighs, stomach, or back, choosing a different location every night.
Gel TT is less structured in that the user can easily change their dosage depending on their specific testosterone levels. As its name implies, gels are semi-thick substances that the user spreads onto their body. The ingredients in gels allow hormones to absorb into the skin similarly to the patch. Users should apply testosterone gel over both of their upper arms, shoulders, and thighs every day. Unlike the patch, gels must be applied to all of the listed locations every day. After application, users must wash their hands thoroughly and cover the treated location with clothing to prevent spreading testosterone to others.
Pellets are the last form of skin-related TT, though they are not transdermal in nature. Pellets are implanted under the skin in fleshy areas of the body. Physicians place this form of TT directly under the top layers of skin (epidermis) using a mild, topical anesthetic. Often, they are placed around the hips or buttocks. Pellets also differ from other skin-related methods of TT in that they only need to be replaced every three to six months.