Introduced to much fanfare a year ago, the Alli diet pill isn’t fattening Glaxo’s bottom line. The over-the-counter weight-loss pill has been tried by about 4 million people since then, but that is less than some Wall Streeters were expecting.

Given the craving among Americans to lose weight, the preliminary figures are “pretty pretty underwhelming,” Steve Brozak, an analyst with WBB Securities, tells the Associated Press. The problem, he says, may be that the marketing campaign stresses the need to transform eating and exercise habits for it to be effective, which isn’t easy to do through advertising. And perhaps people who are willing to make lifestyle changs are less likely to be interested in diet pills, he adds.

But Joe Cadle, director of marketing for Glaxo’s consumer health division, insists, first-year sales point to a “healthy business” that can be sustained and grown as new users try the drug. “We’re the only company with an over the counter product that helps treat something that affects 140 million people,” he tells the AP, but declined to say how tally repeat users.

In clinical trials, people using Alli lost an extra 2 to 3 pounds for every 5 pounds lost through diet and exercise, although side effects include leakages and oily discharges. The marketing campaign warned that meals should be kept to less than 15 grams of fat to avoid effects and pamphlets recommended people bring an extra pair of pants to the office.

Now, though, Glaxo is focusing on telling people that side effects can be avoided if the drug is used properly. So you can keep the extra pants at home? Apparently, so. In fact, Cadle even says the side effects help some people by signaling when they’re not eating right. In other words, there is a silver lining in those orange undies. But don’t look too closely.