The site (www.centrum.co.uk/feelgoodfactor) will run for a year as a loyalty drive. Site visitors are greeted with an interactive quiz that determines their 'feelgood factor' and offers useful information.
The quiz, based on multiple-choice questions relating to aspects of life including work, home, love life, psyche, mind, health and attitudes to friendships, generates users' personal feelgood factor.
Users can buy packs of Centrum at a discounted rate via a link to Pharmacy2U and sign up to receive a free daily or weekly SMS reminder to take the multivitamin. Viral email marketing activity will be used to drive people to the web site.
Alex Lane, account director for Centrum at the digital division of Haygarth, which developed the microsite, said: "Centrum has been making a move in the past 12 months to a brand positioning of complete wellbeing.
"The feelgood factor is about what makes individuals feel good about their life in a fun and interactive way. This is a customer relationship programme. We're adding value by giving users something extra."