Transdermal

Transdermal means absorbed through the skin. Transdermal hormones are patches, gels and sprays, available for both estradiol and testosterone.

Where you'll meet it

In choosing a form of estrogen or testosterone, and especially in conversations about clot risk, where transdermal estradiol is often recommended over tablets.

Why it matters for estrogen

Estradiol taken by mouth goes through the liver before reaching the rest of the body, and that first pass raises clotting factors and SHBG. Through the skin, it skips that step. That is why prescribers often suggest patches or gel for people over 40, smokers, or anyone with a higher risk of DVT.

The practical side

Gels and sprays go on at the same time each day, on clean dry skin, and need a little time to dry. Patches stay on for a few days and can peel, irritate the skin or come off in the heat, which matters if you live somewhere hot or swim a lot. Absorption varies more between people than with injections, so some people struggle to reach their target levels on a patch or gel.

Protecting other people

Testosterone gel especially can transfer to anyone who touches the skin where it was applied, including partners and children, and it can affect them. Covering the area with clothing and washing your hands afterwards are the usual precautions. Also avoid having blood taken from an arm you have just applied gel to, as it can give a falsely high result.

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