Research from the University of Illinois indicates that workplace wellness programs may be ineffective.

The two-year study that gathered responses from 4,800 university employees revealed that these programs had little impact on the respondents health or productivity.

“Wellness programs are widely touted to do all kinds of things: to reduce healthcare costs, to improve employee health, to improve productivity, to reduce the number of sick days employees take,” said David Molitor, a professor of finance at the school’s Gies College of Business and co-author of the report. “Our main thing was to identify what these programs really do and who do they benefit.”

Molitor added the reason that these programs had very few results was that they appealed to those who were already healthy.

Despite having little impact on productivity, the school’s wellness program did increase the amount of employees who had a primary care physician and also boosted their beliefs about their own health.

Still, Molitor said that based on these findings, business leaders should reevaluate their own wellness programs and learn what areas of wellness employees actually want them to invest in.

“We’re not necessarily disappointed when we find out that something doesn’t work,” said Molitor. “That’s really useful to kind of understand this wasn’t working so we can shift our focus to figure out what does work.”