ABC News' Matt Knox and Alison Kenworthy report:
Celebrities swear by it. From Gwyneth Paltrow to Jessica Alba and even Jennifer Lopez, A-listers with glowing skin credit drinking lots of water as one of their beauty secrets.
Health care journalist Sabrina Bachai, of New York City, put the theory to the test, drinking three liters of water a day to see if it would improve her skin.
"I was on Instagram and I saw this girl and I saw that she had beautiful skin and hair and she said she drank three liters of water a day and that was her secret," Bachai, a reporter with medicaldaily.com, told ABC News. "My skin is kind of dry so I figured it would be a good way to see how it worked."
For one week, Bachai drank three liters - 101 ounces of water- a day. That's a little bit more than eight 12-ounce glasses of water.
She says she didn't change anything about her diet, kept her normal gym routine and found it helpful to drink the large quantities through a straw.
"I felt like I was sleeping better," said Bachai. "And I felt like my skin looked fuller."
In addition to feel healthier, she says she lost two pounds.
"I wasn't snacking as much so that helped curb my appetite a little bit," she explained, "because a lot of times when you're hungry, you're not really hungry. You're just thirsty."
But there was one pitfall to the experiment.
"Using the bathroom," she recalled. "I know it's a natural thing and you have to do it, but using the bathroom seven to eight times during the work day, I was going almost every hour."