Product Reviews
Coconut Waters Review -- Tests of O.N.E., Vita Coco, and Zico

Initial Posting: 8/2/11 Updated 12/11/18 

Coconut Drinks Reviewed by ConsumerLab.comSections: Jump to a section by clicking on its name.

What It Is:
Coconut water -- an increasingly popular beverage option for athletes and natural food lovers -- is the clear liquid that sloshes around the inside of immature (green) coconuts. On the beaches of Rio and other tropical locales, you can drink it straight from the coconut. Many grocery and health food stores sell it in cans, bottles, or other more modern packaging.

Coconut water offers an unusual blend of nutrients. It's especially rich in potassium. One cup provides about 500 mg, roughly what you'd get from a banana or a cup of orange juice. It also contains sodium and magnesium and small amounts of phosphorus and vitamin C. It contains no cholesterol and almost no fat, but it does provide a little protein. Natural sugars make it mildly sweet, although it is relatively low in calories compared to typical fruit juices. Coconut water is very different from coconut milk, which is made from the pressed meat of mature coconuts and contains significant amounts of fat from coconut oils.

How It's Used:
Coconut water is a refreshing drink. Because it contains sugar as well as potassium and other electrolytes, it is sometimes marketed as a sports drink for rehydration during and after exercise. It may also be sought out by people who want more potassium in their diets. (See Product Review of Potassium Supplements for more information about potassium.)

Rehydration — How Good is Coconut Water?
When you sweat, you lose minerals as well as water. It only makes sense that a combination of water and minerals is the best way to replenish your supplies. The main mineral in sweat is sodium. In fact, there is about ten times as much sodium in sweat as potassium. So is potassium-rich coconut water really a good way to rehydrate? Several small suggest that it is -- although it is not necessarily better than plain water.

A study that compared coconut water to both plain water and a rehydration drink containing about four times more sodium but far less potassium than coconut water found that all three provided adequate rehydration after a 2-hour period of exercise-induced dehydration (Saat, J Physio Anthro 2002). However, blood sugar levels were restored faster with coconut water and the rehydration drink than with water. An advantage of the coconut water was its palatability. Subjects found it to be sweeter than the sports drink, and it was less likely to upset their stomachs.

Similarly, a small, more recent study found that in young healthy men who performed a 1-hour exercise protocol designed to induce dehydration, pure coconut water (VitaCoco®), coconut water from concentrate, and bottled water each provided similar rehydrating effects compared to a sports rehydration drink (Gatorade®) (Kalman, J Int Sports Soc Nutr 2012), although subjects reported more bloating and stomach upset after drinking both forms of coconut water.

Sodium-enriched coconut water was reported in one small study to provide rehydration (after a 1.5 hour period of exercise-induced dehydration) similar to a sports drink or coconut water not enriched with sodium - each of which restored hydration within two hours of consumption, compared to plain water, which did not. The sodium-enriched coconut water also caused less stomach upset than the sports drink or water (Ismail, Southeast Asian J Trop Med Public Health 2007).

However, the generally small amount of sodium in most non sodium-enriched coconut water products should still be a concern for anyone trying to rehydrate after long-duration, strenuous exercise. Rehydration drinks like Gatorade typically contain 110 mg of sodium per an 8 oz cup (240 mL) serving, and even greater amounts may be useful. Commercial coconut waters made from pure coconut water (not concentrate) claim to contain about 40 mg to 60 mg of sodium in a slightly larger serving (330 mL). And because coconut water is very low in protein or branched chain amino acids, it should also not be considered a sports "recovery" drink to rebuild muscle protein. In large amounts, coconut water may have a mild laxative effect. Obviously, this would make it less effective at replenishing fluids in the long run. 

Prevention and Treatment of Kidney Stones?
Although preliminary research has suggested a possible role for coconut water in preventing kidney stone formation, and some websites claim it can "dissolve" kidney stones, none of this has been proven in people. A study in an experimental rat model showed that coconut water inhibited formation of crystals in the kidney (Gandhi, Int Braz J Urol 2013). A study in healthy adults focused on the ability of coconut water to increase citrate in the urine, as citrate can block the formation of kidney stones. For four days, participants consumed 2 liters (about 8 cups) of coconut water daily. This was switched to tap water for another four days. Compared to tap water, coconut water increased citrate in the urine by an average of 29% (161 mg per day) and, not surprisingly, potassium increased by even more -- by 130%. However, this is not an efficient way to increase urinary citrate: Orange juice is about 4 times as efficient (a single cup can increase citrate by 88 mg); the coconut water provided an extra 108 grams per day of carbohydrates, which was mostly sugar, contributing 416 Calories; and this approach could be dangerous for people who need to restrict their potassium intake (Patel, Biomed Res Int 2018).

Quality Concerns and What CL Tested:
Because coconut water is a natural food product, many different factors can affect the nutritional content. To assess the accuracy of the nutritional labeling of coconut waters, purchased three popular coconut water products. We tested levels of sugars, potassium, sodium, and magnesium. Products were also checked for potential contamination with lead. tests all botanical products for this heavy metal, a common contaminant in such products.

What CL Found:
Among the three products tested, only Zico Natural Pure Premium Coconut Water (414 mL bottle) passed all of our tests. Two others failed to provide their claimed amounts of minerals. No detectable amounts of lead were found in any of the products. Shortcomings of the products were confirmed in two independent laboratories:
  • O.N.E. Coconut Water (330 mL tetra pak) provided only 11 mg of sodium -- far less than the 60 mg it promised. It also came up short on magnesium, providing 19 mg instead of the listed 25 mg.
  • VitaCoco 100% Pure Coconut Water (330 mL tetra pak) was also short on sodium (only 24 mg of its listed 40 mg) and magnesium (only 26 mg of its listed 40 mg). It also contained 16% less potassium than claimed 571 mg instead of the listed 680 mg -- although this amount of variation (+/- 20%) is permitted by the FDA for naturally occurring ingredients in food products.
"A Good Source of Electrolytes"?
The front of the package of O.N.E. Coconut Water claims the product is a "Good Source of Electrolytes." The FDA allows products that provide 10% to 19% of the Daily Value (DV) of a nutrient to claim to be a "good source" of that nutrient. O.N.E is a good source of only one electrolyte potassium, of which it provides 19% of the 3,400 mg adult DV for potassium. To be a good source of sodium, O.N.E. would need to provide at least 240 mg per daily serving; we found it to have only 11 mg. Likewise, O.N.E. was found to have 5% (19 mg) of the daily value of magnesium.

VitaCoco 100% Pure Coconut Water claims to provide more electrolytes than sports drinks. But it, too, had little sodium. While its label claims 10% of the DV for magnesium, which would be 40 mg, CL found it to only have 26 mg disqualifying it as a good source of the mineral. It is true that, like all coconut waters, this product has a lot more potassium than a sports drink; however, it has much less sodium. An equal amount (330 mL) of Original Gatorade, for example, would provide about 150 mg of sodium, compared to Vita Coco's 24 mg.

A bottle of Zico Natural provided a more even balance of electrolytes. The 414 mL bottle contained 160 mg of sodium, several times more than we found in O.N.E. and Vita Coco products and close to the amount you would get from an equal amount of Gatorade. It also had slightly more magnesium (35 mg) than the two other products.

Be aware that Zico sells two different Natural products. We tested the one that comes in a 414 mL bottle and is made from coconut water concentrate. The other is a 330 mL tetra pak containing pure coconut water, similar to the other two other products we tested. The Zico Natural tetra pak lists a much lower amount of sodium (60 mg) than the bottled Zico Natural (160 mg).

Coconut waters are not cheap. The most expensive product that we tested was the 414 mL bottle of Zico Natural at $2.50. The 330 mL tetra pak of O.N.E. was the least expensive at $1.73. A 330 mL tetra pak of Vita Coco cost $1.90.

Coconut Drinks Reviewed by Taste
Coconut water is typically consumed cold, but CL staff drank the products at room temperature to get a better sense of their inherent tastes. The first thing we noticed was a slight variation in the colors of the waters: O.N.E. had a slight pink hue; Vita Coco had a very faint yellow hue, and Zico Natural had no color but was slightly cloudy. All were mildly sweet. O.N.E. had a slightly sour taste, and Vita Coco had a similar but less pronounced tartness. Zico Natural had a milder, less sour but slightly more salty taste, with a bit of a nutty flavor. Its taste is likely the result of "natural flavors" listed as an ingredient as well as its higher sodium content.

Overall Findings
All of the tested products were pleasant tasting. They are certainly a healthier choice than a can of soda or a fruit drink, which contain twice the amount of sugar (a 12 oz, or 355 mL, can of Coke has 39 grams of sugar!). However, they are also somewhat more expensive. Coconut waters are a good source of potassium. If you are using coconut water to help rehydrate, the bottled Zico Natural in a bottle is your best bet due to its more substantial sodium content; our tests found that it contains 15 times as much sodium as O.N.E., for example. Despite a somewhat larger serving size, Zico Natural was in the same low-calorie range (60) as the other two products. Zico was also the only product to live up to the listed amounts of the nutrients we tested. The only drawback is that it's a little more expensive than the other two.

Test Results by Product:
Listed below are the test results of the three coconut waters selected for review by, listed alphabetically. Also shown are the labeled serving sizes and claimed amounts of the key nutrients. If a product is listed as Approved, it was found to contain the labeled amounts of tested nutrients (sugar, potassium, sodium, and magnesium) and did not exceed CL's stringent criteria for lead contamination. The full list of ingredients and nutrients is available for each product by clicking on the word Ingredients in the first column. For more information about testing go to How Products Were Evaluated.

Click on beneath a product name to find a vendor that sells it.

Product Name and Serving Size on Label


Click on "Ingredients" for Full List

Claimed Amount of Key Nutrients per Suggested Serving on Label

(See How Products Were Evaluated)


Met Claim For Electrolytes and Sugars
= Met Claim

If Did Not Meet Claim, Amount Found and Percent of Claim
Did Not Exceed Contamination Limits for Lead
Cost per Serving

(Additional Ingredient Information on Label)
O.N.E. Coconut Water
(330 mL tetra pak carton)

Dist. by One World Enterprises, LLC

Potassium: 670 mg
Sodium: 60 mg
Magnesium: 25 mg
Sugars: 14 g

Sodium: 11 mg (18.3%)
Magnesium: 19 mg (76.6%)


coconut water

VitaCoco, 100% Pure Coconut Water
(330 mL tetra pak carton)

Dist. by All Market Inc.

Potassium: 680 mg
Sodium: 40 mg
Magnesium: 40 mg
Sugars: 15 g

Sodium: 24 mg (59%)
Magnesium: 26 mg (64.4%)


Natural coconut water with added vitamin C (230% of Daily Value of vitamin C2)

Zico Natural (Bottle), Pure Premium Coconut Water
(414 mL bottle)

Dist. by ZICO Beverages, LLC

Potassium: 569 mg
Sodium: 160 mg
Magnesium: 35 mg
Sugars: 12 g
Per 330 mL*
Potassium: 454 mg
Sodium: 128 mg
Magnesium: 28 mg
Sugars: 9.6 g


($1.99 based on 330 mL serving*)

Coconut water concentrate with natural flavors

* Calculated for comparison to O.N.E. and VitaCoco products which are smaller sizes (330 mL) than Zico (414 mL bottle).
1 Potassium amount found was lower than listed but within the naturally occurring levels allowed by Food and Drug Administration (FDA) (+/- 20% of labeled amount). Amount found was 571 mg, which is 84% of the listed amount (680 mg).
2 Not tested, but claimed on label. Daily Value of Vitamin C is 60 mg. (230% of DV = 138 mg of vitamin C.)
Unless otherwise noted, information about the products listed above is based on the samples purchased by (CL) for this Product Review. Manufacturers may change ingredients and label information at any time, so be sure to check labels carefully when evaluating the products you use or buy. If a product's ingredients differ from what is listed above, it may not necessarily be of the same quality as what was tested.

The information contained in this report is based on the compilation and review of information from product labeling and analytic testing. CL applies what it believes to be the most appropriate testing methods and standards. The information in this report does not reflect the opinion or recommendation of CL, its officers or employees. CL cannot assure the accuracy of information.
Copyright, LLC, 2011. All rights reserved. Not to be reproduced, excerpted, or cited in any fashion without the express written permission of LLC.

Concerns and Cautions:
Coconut waters can contain high amounts of potassium and, as noted earlier, in large amounts, coconut water may have a mild laxative effect.

People with severe kidney disease, those taking certain medications, including ACE inhibitors (captopril, lisinopril, enalapril) and potassium-sparing diuretics (eg, triamterene or spironolactone) or other people who need to limit potassium intake should consult a physician. People with type 2 diabetes, especially those with kidney impairment or who take potassium-sparing diuretics, are also at an increased risk of developing high blood levels of potassium from the consumption of coconut water (Devgun, Pract Diabetes 2016). A 78-year-old man with coronary artery disease and type 2 diabetes who was taking spironolactone as well as other medications developed life-threatening high blood levels of potassium resulting in an irregular heartbeat, kidney failure, muscle weakness, and paralysis after consuming 2 - 4 servings of coconut water daily for one week. He recovered completely after medical treatment (Hemachandra, Case Rep Neurol Med 2018). In addition, a 62-year-old man in England with type 2 diabetes (without kidney disease) developed high potassium levels after consuming 1 liter (two 500 mL servings of VitaCoco) daily for two months (Devgun, Pract Diabetes 2015). His potassium levels returned to normal within several months after he stopped drinking coconut water.

Even in people without kidney disease, consuming excessive amounts of coconut water (and therefore, potassium) can be dangerous. A healthy, 42 year old man in the U.S. was admitted to the emergency room for fainting after consuming eight 11-ounce bottles of coconut water (containing a total of 5.5 grams of potassium) in one day while playing tennis outdoors in hot weather. Tests revealed he had dangerously high blood levels of potassium, an abnormal heart rhythm, rhabdomyolysis (muscle breakdown), and acute kidney damage (Hakimian, Circ Arrhythm Electrophysiol 2014). He was released after 3 days of treatment in critical care, and advised to "avoid coconut water, remain well hydrated, and avoid excessive exercise in the extreme heat."

(See the Encyclopedia article for more about potassium side effects and drug interactions).

To further assist consumers, licenses its flask-shaped CL Seal of Approved Quality (see The CL Seal) to manufacturers for use on labels of products that have passed its testing. periodically re-evaluates these products to ensure their compliance with's standards.

Information on this site is provided for informational purposes only. It is not an endorsement of any product nor it is it meant to substitute for the advice provided by physicians or other healthcare professionals. The information contained herein should not be used for diagnosing or treating a health problem or disease.
(9/13/2012): Based on findings from this report, a class action suit was brought against the maker of one of the coconut waters reviewed. As part of settlement of the suit, the company agreed to changes to its labeling and quality control procedures and to provide payments to people who had purchased its products. See the details in the Update in the report.  
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