Welcome to Dear Julia, a column where readers submit everyday health questions. Which over-the-counter painkillers work best? Will intermittent fasting help you lose weight? Julia Belluz sifts through the research and consults experts in the field to figure out how science can help us live happier and healthier lives.

Dear Julia: Can I trust WebMD?

WebMD is the most popular source of health information in the US, and is likely to ​dominate your Google search results for almost any medical question you have. According to its editorial policy, WebMD promises to empower patients and health professionals with "objective, trustworthy, and accurate health information."

But is WebMD actually trustworthy?

While there have been some investigations into WebMD's potential conflicts of interest, there's a remarkable dearth of independent information on this question. The site generates revenue primarily through advertising and sponsored content for pharmaceutical, biotech, and medical device companies, as well as hospitals, health insurance providers, and lifestyle and wellness brands.

The only high-quality study I could find that related to the question of WebMD's independence was published in JAMA in 2013. The researchers looked at which medical communication companies targeting doctors received the most money from 14 pharmaceutical and device companies. They found WebMD, along with its sister site Medscape, were the top recipients of industry dollars:

They're not alone in that regard. Many health companies rely on industry dollars as part of their business model. But those links raise thorny ethical questions, said James Yeh, a physician-researcher based at Brigham and Women's Hospital who has studied the influence of industry funding on medical information.



"This puts [WebMD] in a conflict of interest," he said. "Maybe they are trying to educate the clinician or the public, but at the same time there’s the marketing side: They are also trying to sell a drug."

The site's editorial policy says that it upholds the journalistic principles of honesty and independence. When asked about how the site ensures independence, a WebMD spokesperson said, "The strict editorial practices we have in place ensure that the content we produce is unbiased, and the production of such content done so independent of third party control or influence." They also keep editorial staff separate from advertising staff.



But over the years, others have questioned — and found reason to critique — the site's relationship with drugmakers. In 2010, Sen. Chuck Grassley sent a letter to the site after finding that a WebMD quiz for depression, sponsored by pharmaceutical company Eli Lilly, was rigged to suggest everybody who took the test was at risk for major depression. Naturally, that would make them a potential candidate for antidepressants, conveniently manufactured by Eli Lilly.

In my own perusals of the site, I was bombarded with a dizzying number of ads for pharmaceuticals, hospitals, and sponsored content brought to me by drug companies. On some pages, there were so many ads that actual medical information was difficult to navigate. I also had to click through multiple pages to read anything on a single topic, forcing me to spend more time on the site and see more ads. All in all, it was user unfriendly, and awash in advertising that might confuse someone looking for a solution to a health problem.

Some parts of the site seem to be designed to turn users into patients. The site's popular symptom checker, which allows users to insert basic information about their age, sex, and symptoms, is a hypochondriac's worst nightmare. A search for bloating in the lower abdomen suggested one could have anything from menstrual cramps to ovarian or colon cancers. A query on back pain spit out this terrifying list of potential possibilities: gas pains, shingles, ovarian cancer, acute kidney failure, and tick bites. No context — just a list of scary diagnoses.

The pages on weight loss were a mixed bag. Information about weight loss supplements suggested green coffee supplements might help.* Last time I checked, the government had cracked down on the maker of these pills for bogus peddling, and there's no good evidence behind them. On the other hand, while the site dubiously claims it has "10 easy, painless ways to lose weight," the page actually included some reasonable, if obvious, tips: walk more, hydrate, share restaurant meals.

I also found problems with how the site conveys the effectiveness and possible side effects of some prescription drugs. When I visited the page on weight loss pills, an advertisement on meal replacement shakes popped up, as did an ad for the drug Qsymia — which is among the six drugs featured in the article:

While the site's content is produced by a team of doctors and medical writers, the article failed to mention any basic information about the drug's effectiveness or how many people the drug was likely to help (the number needed to treat, in medical parlance). And some of the information was worryingly incomplete. For example, WebMD didn't note the serious side effects associated with the drug Contrave — it can cause severe, potentially fatal skin reactions and liver failure.

What independent doctors think of WebMD

But those were just my observations after spending a few hours on the site. In the absence of better evidence, I decided to get the views of independent doctors. To do this, I turned to physicians who write or edit pages for UpToDate, which is sort of the anti-WebMD. The subscription-based website, used mainly by doctors to access summaries of the latest medical information, accepts no advertising money as part of its editorial policy and pursuit of independence.

Overall, the doctors I spoke to said they didn't find anything exceptionally egregious about WebMD. But they noted the lack of context around some of the site's medical advice, as well as a smattering of misinformation.

On WebMD's treatments for depression, University of Pennsylvania psychiatrist K. Ryan Connolly found "a few less-than-evidence-based medications listed (Risperdal, Zyprexa)." These anti-psychotics are not approved for major depressive disorder, he said, and both failed to show significant benefits in a number of clinical trials.

Vagus nerve stimulation, a medical treatment that involves delivering electrical impulses to the vagus nerve, was also listed — even though it's no longer considered evidence-based and is almost never done, he said. Meanwhile, one recently approved drug for depression, brexpiprazole, was left out.

Connolly's conclusion: WebMD's depression treatment information is not totally unreliable but is sloppy and incomplete. "It looks mainly like something someone dashed off in an hour," he said. And it could easily give patients a skewed view of their treatment options.

University of Michigan's Sandeep Vijan thought WebMD's cholesterol treatments page was "oversimplified" and "often phrased in an overly frightening way." For example, WebMD suggests cholesterol is "precariously" high in 100 million Americans. "[Precariously] sounds terrifying, but they fail to note that, while [having high cholesterol] is not ideal, it's not the kind of thing that means you'll die tomorrow."

He also noticed inconsistencies in the evidence supporting the use of some treatments that the site recommends: Some were evidence-based (like statins), while others (like fish oil/omega-3 supplements) have no clear evidence of benefit. "It's somewhat superficial, and they don't really get into evidence-based discussions or much about current treatment guidelines," Vijan said.

Again, Vijan noted a range in the quality of the site's information. Some of it "may be fine for an initial introduction for patients," he said. "Hopefully doctors are using something a bit more scientific."

Within the group of doctors I surveyed, some spoke highly of the site. Of the page on psoriasis treatments, Robert Dellavalle, the chief of the dermatology service at Denver's VA medical center, said he didn't spot any errors and thinks WedMD "is doing a great job for a free online publication."

All in all, is WebMD trustworthy? It depends on which page you land on and what you're looking for. The site may be an okay starting point for information, like Wikipedia. But the information isn't always reliable, and unlike Wikipedia, the site's business model relies on the same industry it reports on.

If you want independent information about drugs, check out the Informulary out of Dartmouth. (I've written about it here.) For all medical questions, UpToDate is a great source. (It's mostly paywalled though patient information summaries are free, and again, it has no advertising.) In contrast to WebMD, the nonprofit Mayo Clinic, the UK government's NHS Choices, and the National Institutes of Health's MedlinePlus all have patient-friendly information that's not overrun with advertising. Another nonprofit, Cochrane, is also a solid source with easy-to-understand, "plain language" summaries of clinical evidence. I'd go to all these sites before WebMD, but none is a substitute for seeing a doctor you trust.

PS: Free study idea for researchers — please follow up on my mini survey and test the reliability of medical websites that millions of patients rely on.

Update: On Thursday, WebMD published a statement on their editorial integrity. They also updated their page on weight loss supplements to reflect new information from Natural Medicine, a source for evidence on complementary and alternative medicine. In response to WebMD's statement, Vox has also updated parts of this story, adding more context about WebMD's business model.