Rob Lea Finished the Double Seven Challenge Covered in Diaper Cream and Cow Udder Balm

Completing the Double Seven Challenge—an epic years-long quest to climb the Seven Summits and swim the Oceans Seven—requires a finely tuned gear kit with stress-tested equipment, backups of backups, and a staggering amount of liquid food. But when Rob Lea completed the challenge on June 30, it was partially thanks to something you’re more likely to find in a diaper bag than in a professional gear kit: diaper rash cream.

Why Ocean Swimming Is Brutal on Skin

Even on cloudy days, water can reflect more than 20 percent of UV rays, and those rays can penetrate below the water’s surface. At the same time, water droplets on skin can have a magnifying effect, making UV penetration even more dangerous. The cherry on top? Spending hours upon hours in salt water strips your skin of its natural protective barrier, making you even more susceptible to UV damage.

That’s not even getting into the skin damage of it all. In abrasive saltwater conditions, the human body can break down quickly. Ocean salt, like its kitchen table counterpart, is hygroscopic, meaning it draws water out of your skin’s outer layer. If you’ve ever spent a blissful afternoon floating in the ocean, only to feel like you have alligator skin that evening—that’s why.

Research has shown that when skin comes into contact with salt water, that skin contracts to become almost twice as stiff as skin immersed in fresh water. Plus, saltwater-treated skin experiences more drying stress (think: it felt tight, cracked, or developed small tears) and could be more susceptible to bacteria.

So, what’s an open-water swimmer to do when he needs to spend 12 hours in the ocean? It all starts with diaper cream.

The Diaper Cream Fix

Lea’s skin protection strategy needed to be two-fold: He needed to protect his wet, vulnerable skin from sun damage, and he needed to reinforce its protective barrier to prevent chafing and irritation. And before you ask, a wetsuit wasn’t an option—Lea was only allowed to wear a swimsuit, a cap, and goggles in order to stay within the rules of the challenge.

So Lea and his partner, professional ski mountaineer Caroline Gleich, thought outside of the box. In a behind-the-scenes Instagram Reel that was basically a “Get Ready With Me to Swim the Tsugaru Strait,” viewers can see a gloved Gleich rubbing Desitin Maximum Strength diaper rash cream over every inch of Lea’s exposed skin (and we do mean *every* inch). The diaper rash cream is 40 percent zinc oxide, Gleich notes in her voiceover, and it provides a physical barrier between Lea’s skin and the sun, staying put for up to 12 hours and sealing out the damaging moisture.

On his face, Lea applied Zinka, a similar reef-safe zinc oxide cream that smells marginally better than diaper cream.

With sun protection checked off, Lea and Gleich moved onto skin protection. “Once he’s covered head to toe in [zinc oxide], we load up his armpits, neck, and every other high-friction spot with Bag Balm,” Gleich narrates. Bag Balm is an all-purpose salve that was invented over 125 years ago to soothe irritated, cracked cow udders on a dairy farm. Now, you’re more likely to see it in ski jacket pockets and high-altitude hiking daypacks as an antidote to windburn and cold temperatures—or in the bags of open-water swimmers.

“Eleven-plus hours of salt water will sand your skin raw, so [Bag Balm] is our anti-chafe insurance,” adds Gleich.

One spot that could have used more TLC? The inside of his mouth, which was “raw and swollen” after his swim. “The salt water just kind of eats away at the inside of my mouth,” he told Outside. “It’s like canker sores all over my mouth.”

Although Lea still experienced a little chafing and scorching on some missed spots, he swam the Tsugaru Strait in just under 12 hours and thus completed the last leg of the Double Seven Challenge. We assume he’s recovering by lathering himself in luxurious lotions and hydrating body wraps.