Is drinking extra water good for your skin?

The idea that you’ll have a better(adjective) complexion if you stay hydrated is(linking verb)  so commonplace it’s surprising to discover the lack of evidence to back this up.

If you(personal pronoun) yearn for smooth skin that glows with youth, the chances are that at some point you will have heard the exhortation(direct object)  to drink lots of water in order to flush out those evil(adjective) toxins and keep your skin healthy.

The exact amount(subject)  people suggest varies. US-based advice tends to recommend eight(adjective) glasses a day, while in hotter climates people are advised to drink more to compensate for higher rates of sweating. But regardless of the exact volume of water suggested(participle phrase), the principle behind the advice remains the same – taking extra water on board will keep your skin(singular noun) hydrated. In other words, water(subject) acts like a moisturiser, but from the inside(place adverb)  out.

This is such a common idea you might be surprised at the lack of evidence to back this up. You might expect there to be countless studies where people are(linking verb)  separated into two groups, one assigned to sip water all day(time adverb), the other to drink a normal amount. Then the smoothness of the skin could be assessed a month or so later(time adverb) to establish(transitive verb) whether sipping more led to smoother skin.

In fact such studies are rare, partly because water can’t be patented, so it is hard to find(transitive verb)  anyone to fund such research when there will be no new medication or cosmetic to sell that could repay the costs(plural noun).  A review by the dermatologist Ronni Wolf at the Kaplan Medical Centre(proper noun) in Israel found just one study looking(gerund phrase)  at the effect of long-term water intake(singular noun) on the skin. But the results were contradictory. After four weeks, the group(subject)  who drank extra mineral water(direct object) showed a decrease in skin density, which some believe suggests the skin is(linking verb)  retaining more moisture, while those who drank tap water showed an increase in skin density.(dependent clause). But regardless of the type of water they drank, it made no difference to their wrinkles or to the smoothness of their skin.

That’s not to say that dehydration has no effect on skin. We can measure some effect through the assessment of skin turgor.(independent clause).This is a measure of how fast it(personal pronoun)  takes the skin to return(intransitive verb)  to normal if you pinch some skin and lift it up(action verb). If you are dehydrated your skin will take longer(time adverb)  to get its shape back.

But it doesn’t follow that because drinking too little water is bad for the skin, drinking above average quantities is good. It(personal pronoun)  would be like saying that because a lack of food(common noun)  leads to malnutrition, overeating must be good for us. Or as Wolf puts it, it’s like saying a car needs petrol, therefore the more petrol the better.

Mystery advice

Another common belief is that if you drink extra water the body(singular noun) will somehow store it. But it depends on how fast(manner adverb)  you drink it. Drink several glasses within a fifteen-minute period and you will just pass extra urine. If you spend more than two hours sipping the same amount, more liquid is retained.

There is one study suggesting(transitive verb)  that drinking 500ml of water increases the blood(indirect object)  flow(action verb)  through the capillaries in the skin. But the skin was only evaluated thirty minutes after drinking the water, and what we don’t know is whether this in turn improves(action verb)  skin tone.

One counterargument is that skin contains up to 30% water, and this helps it(indirect object)  to look plump. This may be true, but the skin’s youthful appearance is affected more by factors such as genetics, exposure to the sun and damage from smoking. 

So the mystery is where the eight-glasses-a-day recommendation for good skin comes from. Few(indefinite pronoun)  of the official guidelines even refer to the skin. Water is undoubtedly(manner adverb)  the most important nutrient for the body. Without it we die in a matter of days, and there are of course other health benefits from staying(state verb) hydrated. A review in 2010 found good evidence(direct object) that it reduces the recurrence of kidney stones in those who have already had them, but evidence for other specific benefits is weaker.

Arguments rage over the eight glasses(plural noun) a day rule, with disputes over how much is needed to clear the kidneys of toxins and whether or not water(common noun) helps curb the appetite. It depends on how high the ambient temperature is and how much you are exerting yourself. It’s also a myth that other liquids(plural noun) don’t count. It does not have to be water. Even food contains more liquid than you might expect.  Pizza is 40-49% water, for instance. The percentage of water we derive from food in the diet depends on where you live. In the US it’s 22%. In Greece(proper noun), where people eat more fruit(common noun) and vegetables it is much higher.So the problem is a general lack of evidence that drinking more water makes any difference to your skin. We can’t say it definitely(manner adverb)  does not work(intransitive verb) , but there’s no evidence that it does. Which leaves the question of how much water you should drink. Since it depends on the weather and what you are doing, then there is a very good internal guideline we all(indefinite pronoun)  have that can help(intransitive verb). And that’s thirst.

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