Nevertheless, Henwood, Wyatt, Hart and Smith challenge the extent to which others claim the internet is able to promote self-advocacy. They did research on thirty-two women wanting to know about how hormone replacement therapy (HRT) could relieve menopausal symptoms. [non-primary source They point out that to become informed of one's illness and treatments in this way, requires having skills to be able to access this information using the internet in the first place. Also, one has to start out with some knowledge to distinguish the usefulness of different types of information and decipher what information is valid. As one of their research participants claimed, much information can be gotten from the internet but unlike a doctor, the internet is unable to answer questions about specific information found. Henwood et al. felt that strategies that the patients used for searching for information on the internet were unsystematic. [non-primary source Therefore, research participants were unaware of the commercial interests many sites had. For example, many sites created by lay people are sponsored by large pharmaceutical companies in return for the site's promotion of their drug.