Alkaline water is becoming more and more popular, growing from a niche market to a popular bottled water category with multiple brands that you can find in regular grocery and convenience stores.
But do the health claims of alkaline water companies hold up to scientific research? Is it truly healthier than tap water, or standard bottled water? In this article we’ll investigate.
What Is Alkaline Water?
First it’s important to understand what differentiates alkaline water from other types of bottled water.
The acidity of water is measured on a scale of 1-14 called the pH scale, with lower numbers being more acidic and higher numbers being more alkaline. Many people aren’t aware of this but pH is actually measured on a logarithmic scale, according to the USGS, which means that water with a pH of 6 is ten times more acidic than water with a pH of 7.
Regular tap water ranges in pH level but generally falls around 7, which is neutral (neither acidic nor basic). Alkaline water typically has a pH level of 8 or higher.
Is Alkaline Water Healthier?
Alkaline water companies certainly claim so, but usually without proof.
One medical study on the topic concluded that “Despite the promotion of the alkaline diet and alkaline water by the media and salespeople, there is almost no actual research to either support or disprove these ideas.”
However, more recent studies have found some interesting, although early-stage, results.
An animal study on mice found that consuming alkaline water (at a pH of 9) had an anti-aging effect by increasing telomere length (which regulates cellular aging) and significantly reducing reactive oxygen species in blood.
A 2017 human study found that athletes who consumed alkaline water had “favourable changes” to hydration status compared with athletes who drank tap water. The group drinking alkaline water also had much more efficient lactate utilization, which suggests that alkaline water use during exercise may potentially improve stamina.
A 2019 study in the Medical Gas Research Journal found that daily ingestion of alkaline electrolyzed water containing hydrogen caused significantly positive overall health effects. Study participants drinking alkaline water slept better and experienced reduced gastrointestinal symptoms compared to the control group. The pH of the alkalized water was 9.2. It’s worth noting that this study was funded by an electrical appliance manufacturer (that presumably makes alkalizing appliances), so this study may be biased.
A fourth study on high-mineral alkaline water found that its consumption improved anaerobic exercise performance, supporting the potential performance benefits shown in the previously-linked study.
From these studies we can conclude that there is potential for alkaline water to have health benefits, and specific performance benefits, but the data is still far too early-stage to say definitively.
The research on alkaline water is also so early-stage that there isn’t a medical standard for its use. There is no optimal pH that we know of yet. The studies used different pH levels of alkaline water as well as different secondary factors. Some studies used electrolyzed alkaline water while others used high-mineral alkaline water.
We hope to see more research on alkaline water in the future because much of the popular health media has it wrong on this topic. There is evidence that alkaline water may be healthier than tap water; it’s just too early to provide any recommendations.
There has also been no long-term safety studies that we could find, and those would be necessary to provide research-backed recommendations.
We don’t recommend alkaline water over tap water at this stage because of the lack of long-term safety data. We also believe that legitimate concerns over BPA and other plasticizing chemicals in water may outweigh any health benefits, as most alkaline water is for sale in single-use plastic bottles.
Best Alkaline Water Format
While we don’t recommend alkaline water generally, we do believe that there is a superior format for those who insist on drinking alkaline water: alkaline water filters or whole-house filters to treat tap water.
We know from medical research that the class of chemicals which make plastics soft, called plasticizers, have damaging effects on human health and hormonal activity. These chemicals leach into water of single-use plastic bottles, like nearly all commercial alkaline water bottles.
For this reason, we would recommend using alkaline filters over single-use bottles of alkaline water. Not only are filters more economical and better for the environment, they allow the user to reduce their intake of harmful microplastics. There’s no point in drinking more expensive water for your health if it’s going to contain damaging particles that offset any benefit.
Does Alkaline Water Cure Cancer?
There is currently no scientific evidence suggesting that alkaline water cures cancer, or that it is a useful adjunctive therapy for cancer.
This is a misconception that’s propagated online, and one that is dangerous because of the severity of cancer and the efficacy of conventional treatment.
We recommend that patients with cancer stick to their licensed physician’s recommendations. If you have cancer and want to drink alkaline water, it would be worth asking your physician first. It shouldn't cause any harm, but there’s no evidence suggesting it will help either.