Transdermal patches (adhesive patches placed on the skin) may also be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who are especially physically active and/or bathe often may not be good candidates, since the medication can be washed off and may take up to six hours to be fully absorbed. There is also the risk that an intimate partner or child may come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering AAS for non-medical purposes. 
A key feature of the protocol is that waves are stored on the service provider's servers instead of being sent between users. Waves are federated; copies of waves and wavelets are distributed by the wave provider of the originating user to the providers of all other participants in a particular wave or wavelet so all participants have immediate access to up-to-date content. The originating wave server is responsible for hosting, processing, and concurrency control of waves.   The protocol allows private reply wavelets within parent waves, where other participants have no access or knowledge of them.