Weight loss pills, generally regarded as ineffectual by medical experts, still have a strong following among many people who believe advertisements promising a quick and easy way to drop pounds, a poll indicates.

A survey of almost 3,000 Americans by the National Research Center of Consumer Reports found nearly one in four consumers are willing to be convinced pick up a bottle of weight-loss supplements, despite no scientific evidence of their worth.

"The barrage of advertising leads us to think there's a magic way to melt away 10 pounds -- even when we have no evidence that supplements work," says Pieter Cohen, a Harvard Medical School physician who studies such supplements.

Many Americans are misinformed about the quality and effectiveness of diet pills, and mistakenly believe the Food and Drug Administration guarantees their effectiveness and safety, the survey found.

The Food and Drug Administration does regulate supplements, but more in terms of a food rather than drugs, meaning for the most part they're considered safe unless proved not to be.

That's far from approval of their effectiveness, Cohen points out, but that's not always apparent to consumers.

"The labels on weight loss supplements look like those on over-the-counter medications, and the supplement facts are organized like nutrition facts labels," he says. "There's no way for consumers to tell the difference. It gives you the sense the products are being scrutinized by the FDA."

Many consumers are unaware that supplements have some risks, and full quarter of the people surveyed said they believe diet supplement products present fewer side effects than prescription or over-the-counter medications and are safer than prescription drugs because they seem "natural."

That's not the case, and it holds particularly true for supplements promising significant weight loss, Cohen says.

"Of all dietary supplements, the ones for weight loss seem to cause the most harm -- sometimes liver failure and even death," he says.

Around half of people in the survey who reported they had tried a weight-loss supplement admitted they also experiences at least one symptom such as rapid heart rate, jitteriness, rapid hearth rate, dry mouth or constipation/diarrhea.

Most in the survey said they were also taking prescription medications, which can increase the risk of adverse effects of diet pills, Cohen says.

"These products can interact with prescription medications, but consumers often feel that supplements are different from prescription drugs, and doctors don't ask about them," he says.

Weight-loss supplements will also sometimes contain banned ingredients or substances, further increasing risks in taking them, Cohen notes.

"There's no way to know what's in the bottle," he says. "You're at the mercy of the manufacturer."