If you’re a marketer, here is a tried-and-tested formula to get the attention of consumers: Tell them the product you’re selling is a “miracle” and use lots of feel-good words like “free,” “for a limited time only” and “technological revolution.” This will guarantee your product will get a lot of attention.

If you’re a consumer, however, believing such marketing is a tried-and-tested path to disappointment. When you hear such smarmy words, there’s a good bet somebody is trying to sell you something that’s not so great. Resist the urge to pull out your credit card when something is advertised to be the greatest thing since sliced bread.

Here’s six “sure-bet” miracle products on the market that are actually sure to reveal themselves to be duds, should you ever buy them.

1. Amish Fireplaces. The Amish have long been a source of wonder and admiration from the rest of America. They’re an uncomplicated community, eschewing industrialization and the entrapments of the modern lifestyle. So, a few years back, when the Amish rolled out a fireless fireplace that was declared a technological revolution that would slash home-heating bills, the wonder increased. After all, this The Amish have long been a source of wonder and admiration from the rest of America. They’re an uncomplicated community, eschewing industrialization and the entrapments of the modern lifestyle. So, a few years back, when the Amish rolled out a fireless fireplace that was declared a technological revolution that would slash home-heating bills, the wonder increased. After all, this “miracle idea” earned Good Housekeeping magazine’s lauded Seal of Approval,” so it’s got to be great, right? Not so fast.

In reality, these electric space heaters with glowing faux-hearth fires in wood cabinets are only that—space heaters with moving pictures of fire in a cabinet. They offer no breakthrough in home heating. The only thing a consumer can expect to get out of these $300 cabinets is the warm feeling that they’re buying wooden furniture crafted by the Amish, because the heating elements are made in China.

Here’s something that should have tipped off consumers from the get-go. The television commercials and national newspaper ads showed pictures of Amish craftsmen at work, which might seem a little off, as the Amish are famous for being camera shy . But a little research into the ad’s claims could make consumers even more wary. The Amish Fireplaces are marketed as producing an “amazing” 5,119 BTUs of heat, which really isn’t such a wonder when you find that just about any 1,500-watt heater can produce a similar amount of BTUs.

“There is nothing really amazing about that from an engineering standpoint," Fiona Doyle , an engineering professor at UC-Berkeley told Consumer Affairs. "Whether a space heater costs $40 or $300, 1500 watts cannot magically be converted into more BTU. The maximum amount of heat energy is 1500 watts and it cannot produce more than that."

Consumer Affairs wondered why such a dubious product would get the Good Housekeeping Seal. Good Housekeeping explained:

In order to earn the Good Housekeeping Seal, the Good Housekeeping Research Institute evaluates a product to ensure it meets product claims and confirms that all product promises and directions are accurate. We verify that all information required or recommended on a label is provided. For categories in which there are accepted industry standards, we review the data to ensure the company has followed current performance and safety methods. If a problem about a Seal product is brought to our attention, we investigate it. Products that have earned the Good Housekeeping Seal carry a limited warranty: if the product proves to be defective within two years of purchase, Good Housekeeping will replace the item or refund the consumer.

In trying to decipher this word salad, we can only conclude that the consumer magazine hasn’t found anything to indicate that Heat Surge is making false claims about its product or selling a product that is unsafe.

2. The Fuel Doctor gas saver. The high price of fuel is constantly on the minds of drivers, and this has spawned several gas-saving devices marketed through infomercials, on the Internet, or at the convenience stores that dot our interstate highways. These products typically sell from anywhere between $20 and $250. And they’re all a big waste of money.

Product testing publications such as Consumer Reports and Car and Driver magazine periodically test these products and have yet to find a single aftermarket automotive device or additive that notably increases fuel economy of internal-combustion engines. The EPA lists scores of such devices on its website, and indicates it has gotten similarly disappointing results.

One hot item in this genre is the Fuel Doctor, which claims to increase fuel economy by as much as 25% in cars by conditioning the direct-current voltage of a car’s electronic system. It plugs into a car’s 12-volt power outlet in the cabin, with LED indicator lights that indicate it is operational. The manufacturer claims this will allow for the engine’s electronic control unit to operate more efficiently.

Consumer Reports tested the original Fuel Doctor and found that its electronic components didn’t do much more than power the device’s LEDs.

“When we put it through our extensive testing on a number of vehicles, we found that it made no significant difference in any evaluation. As far as we can tell, all it does is light up when it’s plugged in,” said the organization.

A year later, Consumer Reports tested an updated Fuel Doctor, the Platinum FD-47, and found that it didn’t work either.

This hasn’t stopped the product from being aggressively marketed online and at retailers. Moreover, searching the Internet to discern whether or not the Fuel Doctor works isn't easy, as a website called Fuel Doctor Scam directs those searches to positive reviews of the product. A Domain Tools search of the site conducted by the Rational Wiki blog suggests this might be the work of the manufacturer itself. But as Rational Wiki points out, despite only positive reviews of the Fuel Doctor on the Fuel Doctor Scam site, the product is overwhelmingly down-voted by the site’s visitors.

3. Shake Weights. Back in 2009, Shake Weights became a national phenomenon based almost solely on its campy commercials. The novelty of the product — and its ads — inspired countless Internet parodies and plenty of chatter on television news and talk shows. Originally marketed as an exercise device for women, the original Shake Weight is a 2.5 pound weight that compresses and pulsates as you shake it back and forth (a 5-pound weight for men came out several months later), purportedly increasing the effects of exercise.

The company made great claims about its prowess, stating that "based on a groundbreaking workout technology called Dynamic Inertia, which engages the muscles in the arms, shoulders and chest in an entirely new fashion, the Shake Weight increases upper body muscle activity by more than 300% compared to traditional free weights.”

Shake Weights cost $20 for the women’s version and $30 for men (although they can be found for much less at some retailers). While originally sold only through infomercials, they soon started to appear in department stores, giving the product an air of legitimacy.

Consumer Reports health researchers used electromyography to see how effective the Shake Weights were using the recommended exercises and found they were no more effective than conventional exercise routines targeting certain muscle groups. Consumer Reports' bottom line was that any resistance exercise builds strength, but the Shake Weight is nothing special. In fact, other exercises that target the chest, shoulders and triceps were more effective.

4. Green Coffee. Famously touted as being a “miracle” weight-loss supplement by Dr. Mehmet Oz on his eponymous health-advice talk show, there is no evidence that green coffee does anything to promote weight loss.

A recent laboratory research by the American Chemical Society into the weight-loss claims made by the marketers of green coffee beans finds that the ingredient that is supposed to spur weight loss, chlorogenic acid, has no impact on weight loss. Furthermore, the study showed that it can actually cause fatty deposits in the livers of mice.

While previous medical studies reveal that coffee drinkers have a lower risk of obesity, high blood pressure and insulin resistance (known collectively as “metabolic syndrome”), the researchers found that mice given chlorogenic acid didn’t lose weight compared to mice who were not given the chemical. In fact, the mice who were fed this ingredient had increased insulin resistance in addition to fattier livers.

Yet, on his television program Dr. Oz cited a conflicting study which linked green coffee to weight loss, and said that those who took it lost an average of 18 pounds in six weeks. But the study he cited only involved 16 overweight adults. Further, the study was funded by Applied Food Sciences, a supplement company that manufactures a green coffee bean extract. Moreover, the nutritionist Dr. Oz used on one episode praising green coffee, Lindsey Duncan, had a conflict of interest; he was also the CEO of Genesis Pure, a nutritional supplement company that markets green coffee as a weight-loss product. The show did not disclose these obvious conflicts.

Dr. Oz claimed he did his own two-week test on nearly 100 women, which included a control group that took a placebo. He found that the women who took the supplement as directed lost an average of 2 pounds, while those taking the placebo lost an average of 1 pound. Normally, such results would be deemed inconclusive, at best.

The subjects were also asked to keep food journals, which Dr. Oz admitted might help with weight loss in itself. Still, despite shallow results and sketchy evidence, Dr. Oz proclaimed that “the green coffee bean worked for us” and recommended his audience take it even though “we don’t know much about it.”

Oz’s dabbling in pseudoscience inspired Sen. Claire McCaskill, the chairwoman of the Senate subcommittee on Consumer Protection, to call him to testify and answer questions about his claims. During the testimony, Sen. McCaskill chided Oz for abusing his great influence, saying the products he endorses are almost guaranteed to fly off the shelves.

Oz acknowledged to the subcommittee that while there’s no such thing as a “miracle” supplement, and that many he touts wouldn’t pass scientific muster, he insisted he was comfortable recommending them to his fans.

“My job is to be a cheerleader for the audience,” Oz says. ”And when they don’t think they have hope, when they don’t think they can make it happen, I want to look and I do look everywhere, including alternative healing traditions, for any evidence that might be supportive to them.

5. Baby vocabulary builders. Here’s the lazy parents’ way of teaching language to their toddlers: Park them in front of a television, slip in a special DVD, make sure that nothing babies like to do — like eating, naps, or banging on pots and pans — gets in the way. If everything goes as planned, in short time you’ve got a baby who's got the vocabulary of a four-year-old. Except it doesn’t work that way.

Researchers at UC-Riverside researched whether a popular vocabulary-building video for babies, Baby Wordsworth, actually improved the vocabularies of 12- to 24-month-old toddlers. After parking the kids in front of the television for six weeks, they found that the videos did not work; there was no difference in language acquisition between the babies who watched the videos and a control group that didn’t watch themâ€‹.

This combined with earlier studies indicating possible learning setbacks and deficiencies as a result of watching such videos. Those studies showed that infants who watch such videos actually learn fewer words and score lower on cognitive tests than those who didn’t watch the videos.

Some researchers believe the videos can overstimulate a baby’s brain during a critical early development phase when language skills are acquired. They theorize that babies will learn better if they’re interacting with a live speaker — particularly a parent — who uses language in a repetitive, reinforcing way. The videos, by contrast, teach language passively and the flow of information is one-way, which some researchers believe could over-excite the brain to the point of paralysis.

6. Ear candles. Sometimes what we believe to be ancient alternative-medicine therapies don’t work at all, and sometimes they’re not so ancient. Ear candling is a prime example.

Also known as ear coning, ear candling involves the insertion of a hollow, tapered, waxed-cloth candle into a person’s ear canal, and lighting the end extending from the ear while the subject lies on one side. It’s assumed that the heat from the candle flame creates an updraft and partial vacuum that cleanses the ear, drawing out wax and toxins from the canal. But several studies have shown that there’s no suction element to the candle's function.

Users of the candles claim that they’ve found dark, waxy gunk inside the candles after undergoing this therapy, but it’s actually just a combination of ash and melted candle wax.

There have been many documented cases of people’s ears being injured by the candles. The journal American Family Physician, among other medical journals and digests, warns that ear candles are dangerous.

“In one trial,” notes the journal, “ear candles neither created suction nor removed wax and actually led to occlusion with candle wax in persons who previously had clean ear canals. Primary care physicians may see complications from ear candling including candle wax occlusion, local burns, and tympanic membrane perforation.”

Despite warnings from the medical community, ear candles remain a popular healthcare myth. Several ear candle purveyors have marketed their products falsely, claiming that they’re approved by the U.S. Food and Drug Administration. Some of these companies even market the candles as being safe to use on children, who have a higher incidence of ear infections than adults.

In 2007, the FDA issued a warning to consumers that “the use of a lit candle in the proximity of a person's face would carry a high risk of causing potentially severe skin/hair burns and middle ear damage."

The marketers of ear candles often claim that the practice was used by Hopi tribal shamans, but that claim comes to the surprise of the Hopi tribe who have requested manufacturers not use the tribal name. One manufacturer, BioSun, continues to ignore the Hopi request.

After some research, we could not determine the true origin of ear candles.