User blog comment:Gary299/High School DxD BorN episode 4 review/@comment-3965848-20150427051048/@comment-67.172.91.107-20150427060651

In both instances she needed to be in direct contact (and naked) with him for an extended period of time, and even then, Issei still required further rest after the Freed incident which led him to encountering Asia for a 3rd time. Only after she used her power on his legs did he mention feeling completely healed, so we can say fairly certainly that Asia's sacred gear is massively more effective than Rias's healing powers.