An ice-cold, refreshing beer in the sun is often more tempting than plain water, but does beer hydrate you?
You might assume that any fluid intake should contribute to your hydration level. However, alcohol is more complicated, and consumption of alcoholic beverages may not give you a hydration boost.
We’ve reviewed the latest research to find out whether beer can help you hydrate.
The effect of alcohol on hydration
As we’ve known for thousands of years, alcohol has countless effects on the way our bodies function. Alcohol impacts our cognition, mood, balance (ever had a few too many and seen the world spinning?), speech and many other aspects of our physiology. This includes fluid balance and hydration. Despite alcohol’s historic worldwide popularity, we’re still largely unsure of exactly how it has these effects.
Have your friends at the bar ever joked you were “breaking the seal” as you headed to the toilet? Well, there’s some truth behind the saying. Alcohol is a diuretic, which means it increases your urine output. If you’re peeing out more than you’re taking in, this can have a dehydrating effect.
So – can beer hydrate me?
That’s a good question. It’s been found that drinks vary in their ability to hydrate [1], and different alcoholic drinks have varying hydrating effects, too. So, what effect does beer have?
Alcohol by volume (ABV) is used to compare the alcohol content of different drinks. Most beers have a fairly low ABV, somewhere between 2% and 6% (with some beers such as stouts reaching 10%, similar to most wines). The amount of alcohol in beer is thought to determine its diuretic effect, and therefore how much it can dehydrate you.
When comparing beer (5% ABV), wine (13.5% ABV), spirits (35% ABV) and their non-alcoholic counterparts, one study found that the stronger alcoholic drinks have a short-term diuretic, and therefore potentially dehydrating, effect [2]. Interestingly, they found that urine output after drinking a typical beer was no different than after a non-alcoholic beer or water.
Several other studies have drawn the same conclusion: beer might actually hydrate us adequately [1][3][4]! The studies do warn that stronger beers are likely to be more dehydrating, and that drinks containing essential electrolytes are still better for hydration [4]. Nevertheless, the evidence points to beer not being all that bad from a hydration perspective.
Some people are working on making beers that are better for hydration. They have discovered that adding important electrolytes, like sodium, is a good way of improving a beer’s effect on fluid balance [5]. Other scientists have tested the effect of having a beer, in addition to proper hydration with water, after exercise. They found a beer had no negative effects on rehydration [6]. There’s no more deserving time for a cold beer than after a race, so it’s great news that it doesn’t seem to negatively impact our hydration levels!
Are you concerned about your own hydration levels? Take the quiz below to find the best Hydrant for your hydration routine.
The science behind alcohol causing dehydration 
It’s widely believed that alcohol exerts its diuretic effect by suppressing a hormone called vasopressin, or ADH [7]. Vasopressin usually causes the kidneys to save water instead of passing it as urine. Alcohol therefore inhibits this critical water-saving mechanism inappropriately, which can lead to losing too much water and becoming dehydrated.
However, the studies suggesting this effect on vasopressin are quite old [8][9], so we’ve taken a look at some of the latest evidence to see if modern technology can confirm the theory.
Current studies still agree that alcohol increases urine output [2]. However, they question whether the effect on vasopressin is solely to blame. Several studies have found that increased alcohol intake doesn’t correlate with decreased vasopressin levels [10][11]—so is alcohol really suppressing vasopressin? It’s likely that alcohol causes diuresis, or excessive urination, in ways we just don’t know about yet.
Putting the science aside, the bottom line is that alcohol makes you pee more, causing you to lose more water. And this can potentially cause dehydration.
Is dehydration making my hangover worse?
Probably! Dehydration, electrolyte imbalance, gastrointestinal disturbances, low blood sugar, and sleep disturbance are all suggested as ways alcohol contributes to the awful collections of symptoms that make up a hangover [12].
Sweating, vomiting and diarrhea commonly accompany hangovers. Fluid loss due to the diuretic effect of alcohol increases dehydration and electrolyte imbalance, worsening your hangover!
The splitting headache after a night of drinking is thought to be partly due to the way alcohol causes dilation and constriction of your blood vessels. But dehydration will make that headache worse and leave you feeling even more fragile.
So, of course, nothing is going to beat water (or even better, a drink packed with essential electrolytes such as Hydrant) for hydration. This is especially true when considering the short-term effects of alcohol, such as hangovers, and the damage it can do long term (weight gain, addiction, and even organ failure). However, it’s likely that a weak beer will do a better job of keeping your hydration levels topped up than drinking higher ABV wine or spirits.
Other stories about alcohol & dehydration
If you want to read more about what alcohol does to the human body, click here.
Writer: Charlotte Harrison
Editor: Teddy Angert
References
[1] Oliver, S. et al. (2015). Development of a hydration index: a randomized trial to assess the potential of different beverages to affect hydration status. Nutrición Hospitalaria. 32 Suppl 2, 10264. - This group put together a “beverage hydration index” to show how hydrating different drinks are. Oral rehydration and milk are better than water at hydrating over 4 hours.
[2] Polhuis, K., Wijnen, A., Sierksma, A., Calame, W., & Tieland, M. (2017). The Diuretic Action of Weak and Strong Alcoholic Beverages in Elderly Men: A Randomized Diet-Controlled Crossover Trial. Nutrients, 9(7), 660. doi:10.3390/nu9070660 - This study gave elderly men either beer, wine, spirits or their non-alcoholic counterparts and measured urine output. They found the stronger alcoholic drinks had a greater diuretic effect.
[3] Hobson, R. M., & Maughan, R. J. (2010). Hydration Status and the Diuretic Action of a Small Dose of Alcohol. Alcohol and Alcoholism, 45(4), 366-373. doi:10.1093/alcalc/agq029 - This study showed that weak beer doesn’t worsen mild dehydration, but increases urine output in a person who is well-hydrated.
[4] Wijnen, A. H., Steennis, J., Catoire, M., Wardenaar, F. C., & Mensink, M. (2016). Post-Exercise Rehydration: Effect of Consumption of Beer with Varying Alcohol Content on Fluid Balance after Mild Dehydration. Frontiers in Nutrition, 3. doi:10.3389/fnut.2016.00045 - This study found that an electrolyte-filled sports drink was better at hydrating than a strong beer, but a weak beer didn’t increase urine output more than water.
[5] Desbrow, B., Murray, D., & Leveritt, M. (2013). Beer as a Sports Drink? Manipulating Beer’s Ingredients to Replace Lost Fluid. International Journal of Sport Nutrition and Exercise Metabolism, 23(6), 593-600. doi:10.1123/ijsnem.23.6.593 - This group is looking at how they can change beer to make it better for hydration. They have found adding sodium to beer does this best.
[6] Jiménez-Pavón, D., Cervantes-Borunda, M. S., Díaz, L. E., Marcos, A., & Castillo, M. J. (2015). Effects of a moderate intake of beer on markers of hydration after exercise in the heat: A crossover study. Journal of the International Society of Sports Nutrition, 12(1). doi:10.1186/s12970-015-0088-5 - This study compared men that exercised and rehydrated on only water and those that had a beer in addition to enough water. They found no difference in how well-hydrated they were.
[7] Wiese, J. & Shlipak, M. (2000). The alcohol hangover. Annals of Internal Medicine 132, 897–902. - A review of the effects alcohol has and why this may lead to the dreaded hangover.
[8] Murray, M. M. (1932). The diuretic action of alcohol and its relation to pituitrin. The Journal of Physiology, 76(3), 379-386. doi:10.1113/jphysiol.1932.sp002933 - Early evidence that alcohol causes diuresis by suppressing vasopressin. The study showed that an extract containing vasopressin prevents the diuretic effect of alcohol.
[9] Roberts, K. E. (1963). Mechanism of Dehydration Following Alcohol Ingestion. Archives of Internal Medicine, 112(2), 154. doi:10.1001/archinte.1963.03860020052002 - Similar to the above, they found that a stimulus that increases vasopressin (drinking salty water) reduced the diuretic effect of alcohol.
[10] Linkola, J., Ylikahri, R., Fyhrquist, F., & Wallenius, M. (1978). Plasma vasopressin in ethanol intoxication and hangover. Acta Physiologica Scandinavica, 104(2), 180-187. doi:10.1111/j.1748-1716.1978.tb06265.x - This study measured vasopressin levels in the blood of men drinking alcohol. They found vasopressin actually increased as blood alcohol level increased (the opposite of the believed theory!).
[11] Taivainen, H., Laitinen, K., Tahtela, R., Kiianmaa, K., & Valimaki, M. J. (1995). Role of Plasma Vasopressin in Changes of Water Balance Accompanying Acute Alcohol Intoxication. Alcoholism: Clinical and Experimental Research, 19(3), 759-762. doi:10.1111/j.1530-0277.1995.tb01579.x - Agreeing with the above, this study found that vasopressin levels did not change during diuresis when drinking alcohol.
[12] Swift, R. M. & Davidson, D. (1998). Alcohol Hangover - Mechanisms and Mediators. Alcohol Health and Research World 22(1), 54–60. - A review explaining how alcohol may cause the symptoms of hangover, and some discussion of treatment.
