The internet is teeming with claims that alkaline water does everything from killing cancer cells to providing superior hydration. Here's the evidence.

"Ideally, I recommend water that’s at least [a pH of] 9.5,” writes Robert O. Young in his book The pH Miracle.

In June 2017, Young—who charged people thousands of dollars to attend his “pH Miracle” retreats—was sentenced to nearly four years in prison for practicing medicine without a license. He also admitted to having no college education. (His “Ph.D.” apparently came from a diploma mill.)

On the (0 to 14) pH scale, pure water is 7—that is, it’s neither acidic nor alkaline. Some companies sell water that is naturally alkaline (with a pH of 8 or 9) because it’s higher in potassium, magnesium, or calcium. You can also buy (expensive) machines that “electrolyze-reduce” water to make it alkaline. Or you can pick up an electrolyzed-reduced water—Essentia is a popular brand—at the supermarket.

Proponents claim that alkaline water kills cancer cells, banishes belly fat, lubricates joints, and more. Two of the most common and best-studied claims: it reduces acid reflux and improves hydration. But the evidence is skimpy:


The claim largely rests on one test-tube study in which alkaline water with a pH of 8.8 inactivated pepsin, a stomach enzyme that the study authors claim is responsible for the tissue damage caused by reflux.1

“You can get a petri dish to a pH of 8.8, but that’s going to be pretty hard to do in the stomach, which is so acidic that it has a pH of 1.5 to 3.5,” says gastroenterologist Scott Gabbard, of the Cleveland Clinic. “It would probably take many liters of alkaline water to do so.” What’s more, says Gabbard, “pepsin helps digest proteins. Inactivating it would be a bad thing.”


“We make supercharged ionized alkaline water that’s better at rehydration,” claims Essentia’s website.

Its evidence: after company-funded researchers had 100 adults exercise until they were dehydrated, only one of several measures of hydration that the researchers used—blood viscosity, or blood thickness—improved more in those who drank Essentia than in those who drank ordinary water.2

“I’ve never heard of anyone measuring hydration using the method used in this study in my 30 years of research,” says Lawrence Armstrong, a professor of kinesiology at the University of Connecticut.

“This study used only one good way to measure hydration, and it didn’t find any difference between groups. I have multiple concerns about this research. I would have rejected this paper, had I been one of the peer reviewers.”

The bottom line

Don’t waste your money on alkaline water.


1Ann. Otol. Rhinol. Laryngol. 121: 431, 2012.

2J. Int. Soc. Sports Nutr. 13: 45, 2016.