Hardy, who was previously interim sales and marketing director at RAC, will work alongside Phil Geary, marketing director at Holland & Barrett, overseeing a team of 50.
She will report to chief executive Peter Aldis and will focus on the firm's multi-channel offering, as well as assisting with the firm's ongoing ad review.
The group, which also operates GNC and Nature's Way, has a network of 800-plus UK stores and 30 franchised stores across the globe.
Aldis said: "We welcome Lysa to the business and the corporate board and I are confident she will help us achieve our objectives of enhancing the wellbeing of our customers globally, by delivering the highest quality, best-value nutritional supplements and wellness products."
Hardy spent nine months at RAC. She previously worked at mobile operator Everything Everywhere, which this month rebranded as EE.