Alkaline Water: Benefits, Side Effects And Dangers (2024)

The alkalinity of water refers to its pH, which is measured on a scale of zero to 14 based on its relative alkaline (basic) or acidic nature. A liquid with a pH of seven is considered neutral. Meanwhile, a liquid with a pH closer to zero is more acidic, and a liquid with a pH closer to 14 is more alkaline.

There are several ways to make water more alkaline. A process called electrolysis uses a device with an electric current to split water into acidic and alkaline components. The alkaline component is then saved for bottling. Adding certain minerals, such as calcium, sodium, magnesium and potassium, to water can also make it more alkaline.

How Is Alkaline Water Different From Plain Water?

Purified drinking water is neutral, with a pH around seven. In contrast, alkaline water has a higher (more basic) pH, typically ranging from eight to 10. Alkaline water may also contain more minerals than non-alkaline drinking water if minerals like calcium and potassium are added to increase and maintain the alkalinity of the water.

“[Some people] suggest that [alkaline water] can help neutralize acid in the body, improve hydration and boost the immune system,” says Ronald Smith, a registered dietitian nutritionist based in Connecticut. However, the potential benefits related to drinking alkaline water lack robust scientific evidence at this point in time, he adds. Larger and more rigorous clinical studies are needed before alkaline water can be universally recommended as a health promoting beverage.

With that said, a few small studies suggest that drinking alkaline water may have potential health benefits, including increased hydration, bone health support and a reduced risk of kidney stones.

Hydration

A small 2017 study of 36 male soccer players in Biology of Sport investigated the effects of drinking different types of water on hydration and post-exercise lactate use after strenuous exercise. Lactate, also known as lactic acid, is a byproduct produced by the body during exercise. When it builds up, it can cause a “burning” sensation that is often associated with strenuous exercise. Researchers found that alkaline water with no added minerals was associated with better hydration and improved lactate utilization (i.e., less accumulation of lactate)^[2]Chycki J, Zając T, Maszczyk A, Kurylas A. The effect of mineral-based alkaline water on hydration status and the metabolic response to short-term anaerobic exercise. Biol Sport. 2017;34(3):255-261. . Larger, more comprehensive clinical trials are still needed to further support these findings.

Bone Health

A small 2009 study in the journal Bone examined the effects of both calcium-rich acidic mineral water and bicarbonate- and calcium-rich alkaline mineral water on bone health among 30 female participants. Those who were randomly placed in the alkaline water consumption group showed fewer markers of bone resorption (the destruction of bone tissues that leads to bone loss) than women assigned to the acidic mineral water group^[3]Wynn E, Krieg MA, Aeschlimann JM, Burckhardt P. Alkaline mineral water lowers bone resorption even in calcium sufficiency: alkaline mineral water and bone metabolism. Bone. 2009;44(1):120-4. . A more recent 2021 study demonstrated that of 100 postmenopausal women, participants who drank alkaline water demonstrated enhanced bone density markers, suggesting that further studies are warranted to explore the impact alkaline water may have on treating osteoporosis^[4]Fasihi S, Fazelian S, Farahbod F, Moradi F, Dehghan M. Effect of Alkaline Drinking Water on Bone Density of Postmenopausal Women with Osteoporosis. J Menopausal Med. 2021 Aug;27(2):94-101. .

Kidney Stones

When it comes to kidney stones, alkaline water can be hit or miss, explains Marc Richards, M.D., a board-certified nephrologist in Florida. Drinking calcium-enriched alkaline water could make the urine more alkaline, theoretically preventing certain types of kidney stones, such as those caused by oxalates (which represents about 90% of stones), he says. Calcium binds to oxalates, which are naturally-occurring compounds found in plant-based foods, in the gut, thereby preventing the development of a stone, he says.

Drinking alkaline water may have several side effects, according to Smith, including:

• Altered blood pH. Since alkaline water has a higher pH than tap water, drinking large amounts could potentially slightly alter the body’s natural pH balance, says Smith. However, this imbalance is unlikely to occur, as the body is able to maintain proper pH levels on its own thanks to the functions of the kidneys and lungs.

• Digestive problems. Drinking extensive amounts of alkaline water may result in digestive issues like nausea, vomiting and stomach pain, says Smith, though this effect is unlikely.

• Interference with medication absorption. When consumed in large quantities, alkaline water may interfere with the absorption of certain medications because of how it could affect the stomach’s pH, explains Smith. If the pH of the stomach becomes too alkaline, it could speed up the absorption of acidic medications, leading to the medication entering the blood too quickly. In contrast, an alkaline stomach pH could lead to alkaline medications not being absorbed fast enough. Similar effects are seen with medications that are used to treat heartburn (which also increase the pH of the stomach).

Is Alkaline Water Dangerous?

There may be some risks associated with drinking alkaline water for people with chronic kidney disease, explains Dr. Richards. “In patients with chronic kidney disease, especially [when the disease is] caused by high blood pressure or heart disease, excess fluid can actually be harmful,” he explains. However, this risk exists with all forms of water—not just alkaline water.

If you’re interested in incorporating alkaline water into your hydration routine, speak with your health care provider and/or a registered dietitian nutritionist, especially if you have a history of chronic health conditions.

If you have a history of kidney disease, it’s best to speak with your nephrologist before incorporating alkaline water into your routine.