Fact check: Experts say pinch test on hand can measure hydration – USA TODAY

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The claim: A skin pinch test on the hand can be used to check for dehydration

A video circulating on social media claims to show a quick and effective method for checking oneself for dehydration.

The video shows two people pinching the skin around the top of a knuckle so it forms a small fold.

“To see how dehydrated you are, you have to squeeze your fingertip right here and if it goes back down, you’re hydrated,” reads text included in the video. “If you squeeze it and it stays up like this, you’re dehydrated.”

One Oct. 2 Facebook that shared the video was viewed more than 25 million times. Some commenters expressed doubt at the process described.

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But an expert told USA TODAY the skin pinch method is a legitimate way to measure dehydration, which occurs when one loses more fluids than one takes in. The condition can be reversed quickly by drinking water or eating foods with a high water content, such as cucumbers and watermelon. 

USA TODAY reached out to the user who shared the claim for comment. 

Top of the hand is more accurate than a knuckle for dehydration test

Lauri Wright, a professor at the University of North Florida and a spokesperson for the Academy of Nutrition and Dietetics, told USA TODAY the skin pinch test is a valid way to assess hydration levels.

As the video claims, Wright said a person who is well-hydrated will see their skin go back into place very quickly after the pinch, while a dehydrated person’s skin will stay tented. 

However, Wright said the top of the hand is a more accurate place to perform the test than the knuckles, which can be affected by conditions like arthritis. The skin in the area between the wrist and the base knuckles includes both intercellular and extracellular fluid, which makes up 60% of body weight

“The knuckle represents synovial fluid, which is a very small percent of total body fluid and therefore not as sensitive to dehydration,” Wright said. 

The website for MedlinePlus, a service of the National Library of Medicine, also shows the test being performed on the top of the hand.  

Dehydration can affect all age groups, but young children and older adults are particularly vulnerable to the condition, according to the Mayo Clinic.

Wright said those whose pinch test indicates dehydration could see a different result within 15 minutes after rehydrating. In extreme dehydration cases, which MedlinePlus defined as fluid loss that equals 15% or more of body weight, IV insertion may be necessary. 

More: Across the US, towns warn of toxic PFAS chemicals in drinking water. Here’s what to know.

The pinch test claim also circulated online in 2021. Dr. Karen Raj, a doctor for the U.K.’s National Health Service, confirmed the legitimacy of the method at the time in a TikTok video that was shared more than 60,000 times.

Our rating: True

Based on our research, we rate TRUE the claim a skin pinch test on the hand can be used to check for dehydration. An expert said well-hydrated skin will snap back into place quickly, while dehydration will leave it tented. Mild cases of dehydration can be resolved quickly by consuming more water. 

Our fact-check sources: 

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