Existing anonymous remote authentication protocols to secure wireless body area networks (WBANs) raise challenges such as eliminating the need for distributing clients' account information to the application providers and achieving forward security. This paper efficiently addresses these challenges by devising a scalable certificateless remote authentication protocol with anonymity and forward security for WBANs. Different from the previous protocols in this field, our protocol not only provides mutual authentication, session key establishment, anonymity, unlinkability, and nonrepudiation, but also achieves forward security, key escrow resilience, and scalability. Performance evaluation demonstrates that compared with the most efficient ID-based remote anonymous authentication protocol, our protocol reduces at least 52.6% and 17.6% of the overall running time and communication overhead, respectively, and the reduction in the computation cost and communication overhead achieves at least 73.8% and 55.8%, respectively, compared with up-to-date certificateless remote authentication protocol with anonymity.