Upon retirement at age 33, Nick Symmonds made plans for Hawaii, for a trip much more than R&R.

Symmonds, a two-time Olympian and six-time U.S. champion at 800 meters, will run his first marathon on Sunday at the Honolulu Marathon. The race is also an outlet to promote his product, Run Gum, a caffeinated gum that provides an energy boost.

“Now I can really focus on my business but I’m not ready to stop running completely,” said Symmonds. “I want to run this marathon and I have a couple of other goals before I hang up my shoes. Running a marathon is something I always wanted to do. You can’t really do that when you’re training for the 8. It’s too big of a risk for injury.”

Symmonds, who ran at Division III Willamette, decided in January this would be his final year as a professional athlete, and June’s U.S. Championships culminated a lengthy career. He initially thought his pro career would last a few years, then he’d start medical school. He thought he’d peak in his mid 20s and retire soon after. Medical school never happened, and Symmonds peaked in his late 20s and continued into his 30s. He ran in the 2008 and 2012 Olympics and was a silver medalist at the 2013 world championships.

“I just wanted to run until my body said it couldn’t handle it anymore,” Symmonds said. “Twenty years of running around a track destabilized my left ankle to the point where I can run 26 miles on Sunday pain free but if you asked me to run a lap around the track right now, I don’t think I can do it pain free.”

He developed Run Gum in 2014 while sitting out an injury. His biochemistry degree provided the knowledge to develop the product, as did his running background. As an athlete he wanted an energy boost in a form that wouldn’t slosh around in his stomach while running.

“We took the actives out of an energy drink, mainly caffeine, taurine, and B vitamins, and then infused it into a piece of chewing gum,” Symmonds explained. “So the gum becomes the delivery vehicle and you absorb the stimulants sublingually instead of in your stomach.”

Throughout his career, Symmonds has been vocal about issues, most notably athletes’ rights. Run Gum filed an antitrust lawsuit against the U.S. Olympic Committee and USA Track & Field, arguing an athlete could wear their own sponsor’s logo during the U.S. Olympic Trials. Only logos of select apparel and shoe companies are allowed.

A U.S. District Court judge dismissed the suit last year, but the issue continues in a sport where most athletes live off sponsorship deals.

“We want to fuel athletes, we want to inspire them and provide a fair playing ground for them when they compete,” Symmonds said.