It's not easy being the world's most recognized product. Coca-Cola's (KO 0.45%) signature soft drink has long been dogged by rumors, running the gamut from almost believable to way-out wacky.

Have you been told, for example, that a well-known child actor died when consuming Coke with Pop Rocks candy? Or that a penny/t-bone steak/human molar left in a glass of it will dissolve overnight? How about, when spiked with MSG, it has aphrodisiac properties?

None of those things are true, of course. The same goes for these four blatantly false, yet somehow very persistent, myths about Earth's most popular soft drink.

Source: Coca-Cola. 

1. Only two people in the world know its secret formula -- a pair of Coke executives -- and each has memorized only half of the recipe.
The sheer global vastness of today's Coca-Cola Company is nearly proof in itself that this is bunk -- there's no way in heck the recipe for a product made in such volume is going to live only inside the heads of two people. Coke does little to downplay this old fairy tale, as the air of mystery and exclusivity provides fantastic (not to mention, largely free) publicity. The "two guys" myth appears to stem from an old company marketing campaign. Coke says little about how many people actually know the formula, but it's certainly well out of the single digits.

Meanwhile, the company makes a big show of holding the "only" "original" paper copy of the recipe in a sealed vault at its World of Coca-Cola museum. Yet through the years, outside parties -- such as podcast This American Life -- have unearthed what seem to be other genuine copies.

2. The development and sale of the "failed" New Coke in the 1980s was, in fact, a very clever marketing ploy by the company.
In 1985, in order to combat eroding market share, Coca-Cola launched New Coke, made from a different (and cheaper) recipe than its predecessor. It was a disaster, meeting with near-violent resistance from the Coke faithful. Within months, it was replaced with the "Classic" version, which sits on shelves to this day.

Some claim this was a devilishly clever move to create demand for the original drink, generating immense word-of-mouth about the company and its "lost" product. Since then, though, Coca-Cola has publicly owned up to its stupidity in conceiving a product no one wanted. Ditto for several of its executives at the time, and others involved in the launch. Also, the company's ambitions to update the drink's taste are documented, dating back to the mid-1970s, when research was begun on a new version. At the time, this truly was top secret and conspiratorial -- it even had a cover name: Project Kansas.

3. Mexican Coke is made with cane sugar (as opposed to high-fructose corn syrup), so it's more pure and thus healthier to drink
Here's a falsehood that's gotten a lot of traction lately. But come on, folks, we're talking about Coke, here. None of us are consuming it for the benefits it confers on our organism.

HFCS is still a relatively new food additive, so despite its reams of bad press, we don't know much about its effects on the body. What we do know indicates that it essentially produces the same effect as consuming white sugar, as the two substances are close in composition -- the former is half glucose, and half fructose. For HFCS, that proportion is 45%/55%. So basically, we're pouring the same stuff into our body, no matter the country of origin.

4. It's effective as a household cleaner.
Coke is mildly acidic. So like vinegar, for example, it should theoretically be able to cut though some tough dirt and stains. Although with much sweat and strain it does, we can't call it "effective" -- dedicated specialty cleaning products work much more quickly on dirt and grime. And of course, when you spread Coke all over the place, you have to clean that up the sticky, sugar-heavy soda mess, too. This is generally not a necessary step when using a more traditional cleaning liquid.