Once Charles “Kid” McCoy became the American welterweight boxing champion in 1896, a number of lesser boxers started claiming to be the Kid as a way to get more lucrative fights. The scheme soon became well-known, though, and stopped working.

But when the actual Kid entered a bar one night, one inebriated patron demanded proof he wasn’t just another poseur. One punch later, the knocked-down drunk looked up, jiggled his jaw, and said, “Now that’s the real McCoy.”

Now that’s a really good story, but maybe not why someone or something genuinely authentic has come to be called “the real McCoy.” For 40 years before McCoy ever became a boxing champion, the MacKay family in Scotland began using a variant of it,“the real MacKay,” as the slogan for the whiskey they sold.

But more likely the phrase is in reference to the Canadian inventor Elijah McCoy, who made a machine for lubricating steam engines in 1872 that was so good it led to knockoff after knockoff yet never anything quite as good.

And even more likely is that you’re wondering about the reason for this lesson in folk etymology.

It’s because of something I’ve written here at least twice before. That, unless you have kidney disease or a kidney impairment, you should be taking 5 milligrams of creatine monohydrate every day until you die as a way to help you health.

According to an article contained in the July 2021 issue of Nutrients, however, 87 percent of adult Americans who see themselves as active but not quite an athlete do not do so. And since I have no desire to go about punching out that many people, here’s yet another in a long list of studies, this one published in the July issue of the Journal of the International Society of Sports Nutrition, that demonstrates creatine’s the real McCoy.

In it, researchers recruited 64 healthy but sedentary adults between the ages of 45 and 64, to participate in a 12-week diet intervention where half would also exercise three times a week. What was explained to the participants as a further matter — but was actually the motive the study — is that they would be expected to add a 5-gram packet of something to water or a flavored beverage twice a day and drink it.

For a randomly selected half, the something was maltodextrin. While technically not a sugar, maltodextrin functions as one, for it easily gets broken down into glucose by the body; therefore, it’s often used in energy drinks, sports gels, and similar products.

For the others, the something was creatine monohydrate, the most affordable and possibly most effective, type of creatine available.

At the beginning, middle, and end of the study the participants, gave blood samples, took a number of cognitive and memory tests, and had their body composition assessed.

Those exercising did so thrice a week and did rather standard stuff: weightlifting where each exercise was done for 3 sets of 10 reps, with the amount of weight increasing every week or two; cardio done in some way indoors for 20 minutes at an effort between 60 and 80 percent of the participants’ maximum heart rate. The diet followed by all aligned with the American Heart Association’s macronutrient recommendations (55 percent carbohydrate, 15 percent protein, 30 percent fat) and was designed to induce a “modest energy deficit” of approximately 300 to 500 calories per day.

By the end of the study, as you might expect, those who exercised and took creatine monohydrate improved their muscular strength as well as their amount of lean tissue mass. In addition, they also experienced a greater reduction of body fat and “favorable changes” in some of their cognitive and memory test scores.

But here’s what even the researchers couldn’t have expected. The participants who did no exercise but took creatine also improved their lean muscle mass and strength.

What this tells us, Richard Kreider, PhD, FACSM, director of the Exercise & Sport Nutrition Lab at Texas A&M University and author of the study, tells Allison Forsyth for an article for Health is “anybody can take creatine and get some benefit.”

What it should tell you is that creatine is more than the real McCoy, but the king of all supplements. If that sounds like hyperbole, consider all the new stuff researchers have discovered about creatine in just the last year or so.

That it helps maintain memory during times of sleep restriction, helps preserve cognitive function in those with Alzheimer’s disease, lessens the fatigue that comes with long COVID, and that those who get a good bit of it through food have a reduced the risk of developing all forms of cancer.

And let’s not forget the good creatine supplementation does for those working out. In 2017, the Journal of the International Society of Sports Nutrition called creatine “the most effective ergogenic nutritional supplement currently available to athletes in terms of increasing high-intensity exercise capacity and lean body mass during training.”

Furthermore, a review published in the 2019 issue of Biomolecules determined that taking creatine along with lifting weights “may be an effective dietary strategy to combat age-related muscle atrophy and sarcopenia” by “increasing capacity for higher intensity exercise, and/or by enhancing post-exercise recovery and adaptation.”