Transdermal estrogen involves delivering the hormone estrogen directly through the skin into the bloodstream. Estrogen is a group of hormones produced primarily by the ovaries in females. It plays a role in the female reproductive system, secondary sexual characteristics, and influences many bodily systems including bones, the cardiovascular system, and the brain. This application bypasses the digestive system.
How Transdermal Estrogen is Absorbed
The skin acts as a barrier, but transdermal estrogen formulations are designed to allow the hormone to pass through its layers and enter the systemic circulation. Once applied, the estrogen penetrates the outermost layer of the skin, the stratum corneum, and then moves into the deeper layers. Tiny blood vessels called capillaries within the dermis absorb the hormone, distributing it throughout the body.
This method of delivery allows for a controlled and sustained release of the hormone into the bloodstream. Unlike oral estrogen, transdermal administration avoids the “first-pass metabolism” in the liver, where a significant portion is processed and broken down. This direct absorption into the bloodstream helps maintain more stable hormone levels.
Common Applications
Transdermal estrogen is frequently prescribed to manage symptoms associated with menopause. As estrogen levels decline during menopause, women experience symptoms such as hot flashes, night sweats, and vaginal dryness. Transdermal estrogen alleviates these issues by supplementing the body’s diminishing hormone supply.
Beyond menopausal symptom relief, transdermal estrogen also plays a role in preventing osteoporosis in postmenopausal women. Estrogen is important for maintaining bone strength; its decline after menopause can lead to bone density loss. This delivery method increases bone mineral density and reduces the risk of fractures. It can also be used for conditions where a woman’s ovaries do not produce enough estrogen naturally.
Forms of Transdermal Estrogen
Transdermal estrogen is available in several forms, each with specific application methods. Patches are adhesive systems applied directly to the skin, on the lower abdomen, hips, or buttocks, and are changed once or twice weekly depending on the brand. These patches deliver a consistent level of estrogen over several days.
Gels and sprays offer alternative application methods. Estrogen gels, such as EstroGel or Divigel, are applied to a large area of clean, dry skin on the arms or thighs, once daily. Sprays, like Evamist or Lenzetto, are applied to the forearm, with a measured dose delivered per spray. The number of sprays can be adjusted based on individual needs and clinical response. Creams are another topical option, applied to specific skin areas.
Advantages of Transdermal Delivery
A primary advantage of transdermal estrogen delivery is its ability to bypass the liver’s first-pass metabolism. By avoiding this first-pass effect, transdermal estrogen results in more stable and physiological hormone levels in the bloodstream. This reduces the risk of side effects like blood clots and gallbladder issues, associated with oral estrogen.
Transdermal methods allow for lower effective doses of estrogen compared to oral forms, as less hormone is metabolized before reaching target tissues. Transdermal application is a convenient option for some individuals, and it leads to fewer gastrointestinal side effects.
Important Considerations for Use
Proper application technique is important for effective transdermal estrogen use. For patches, the application site should be clean, dry, and hairless, and the patch should not be cut or trimmed. Rotate the application site to reduce skin irritation. For gels and sprays, apply the product to designated skin areas and allow it to dry completely before covering or contact with others, to prevent accidental transfer.
Common side effects associated with transdermal estrogen include skin irritation at the application site, breast tenderness, and headaches. Nausea, stomach pain, or bloating may also occur. While serious side effects are less common, it is important to be aware of symptoms such as sudden severe headaches, speech problems, or sudden vision loss, which warrant immediate medical attention.
Medical supervision is necessary when using transdermal estrogen. A healthcare professional determines the appropriate dosage, which may be adjusted based on individual response and symptoms. Regular evaluations ensure the treatment remains suitable and effective. Discuss any existing medical conditions, such as a history of certain cancers or blood clots, as these may affect the suitability of transdermal estrogen therapy. For women with an intact uterus, a progestin is prescribed alongside estrogen to reduce the risk of endometrial changes.