Anyone who has experienced the decline and loss of pet knows the emotional pain that accompanies it.

Brian Larsen was 18 when his beloved Bandit - an arthritic Siberian husky - died after a long bout with cancer. The painful experience proved pivotal, inspiring a resolve to help pets live better lives and what he views his calling. Now 33, Larsen is the founder and chief executive of RestoraPet, a Gaithersburg, Marylandd-based maker of pet supplements.

He said his special blend of 12 antioxidants works this way: "As you get older, your cells start to break down. Free radicals attack your cells and your DNA. RestoraPet goes in and stands guard and says, 'take a piece of me instead of the cell.' It protects the body."

I wasn't sure what to make of this mission-driven business venture. I haven't had a pet since my Labrador retriever passed away nearly a decade ago, and I'm somewhat dubious about health supplements.

But Larsen clearly has found a niche: RestoraPet is now sold in 90 countries and is on track to gross more than $2 million this year.

Larsen has 15 full-time employees, including five at the 8,000-square-foot factory where the supplements are mixed and bottled, and said he expects revenue to reach $10 million next year.

Though I'm a bit skeptical RestoraPet can boost revenue at such a fast pace, Larsen has the financial backing of Morton Meyerson, a big-time Texas businessman and former computer industry executive. Meyerson, 81, helped make the late H. Ross Perot one of the richest men on the planet.

"Pets are the new children," said Meyerson, the former chief executive of Perot Systems and the one-time chief technology officer at General Motors. "It's a huge market where billions are being spent."

I visited RestoraPet's factory and offices a few weeks ago. There were yellow barrels housing 250 gallons of Tunisian olive oil that serve as a base for the supplement. There was a new, $220,000 assembly line that fill more than 1 million 2-ounce bottles each year.

RestoraPet comes in bacon, beef or no flavor for dogs, tuna for cats, and apple-carrot for horses. Owners can either sprinkle a few drops in their pet's food or in its mouth. The company has 10,000 or so regular customers, and thousands of followers on Facebook and Instagram.

The company is in the fifth year of a business model built around cultivating a recurring revenue stream. Though carried by a handful of independent pet stores and veterinarian offices, most sales are done online. The company is now moving toward a subscription model. A month's supply currently runs about $30.

"Everybody loves the subscription model," Larsen said. "If they have to keep ordering it, they will forget to come back and buy it. Then their pet has regressed."

Alexander Starr, a veterinarian at Scarsdale Animal Hospital in New York said the supplements are effective, "especially on older patients."

"They have more energy, are happy," he said. "It's the observation of their behavior and their general mood. You can tell the difference."

Many pet owners seem to agree.

"My 16-year old cat has chronic kidney disease. I noticed a change in her a week after giving her this tonic. More jubilant, stronger, and happier," a reviewer wrote on Amazon. Another customer bought a bottle for an elderly lab named Coco. "I'm always skeptical of placebo effects (and this product seemed kind of expensive), so I only bought one bottle to start with, but I have to say, the difference I've seen is STRIKING." (Amazon founder Jeff Bezos owns The Washington Post.)

It didn't get high marks across the board. A one-star reviewer said it "did nothing" for their 12-year-old Pomeranian. And several grumbled about the $30 monthly outlay for a 2-ounce bottle.

"We market our product as visibly improving quality of life for pets, and it does that in the vast majority of cases," Larsen said. "If someone doesn't notice a difference in their pet, we usually find it's because they either didn't try it for long enough, they didn't give it every day or their pet's problem is not age-related."

Larsen has been working since he was 15, when he obtained a work permit to take a job at Target near the family home in Laurel, Maryland. His father was a Machinist at the Government Printing Office and his mom was a homemaker.

"I am 100 percent blue collar," he says.

There was a lot of illness in his immediate and extended family growing up, "so I think I was always fascinated by what chemicals can do to our body. They literally can keep us alive. Being around so many ill people, I think I learned to respect the value of pharmacology."

That led to a desire to work in a pharmacy, which he did at Target after being a cashier. He spent hours reading the Physician's Desk Reference to understand basic pharmacology and how medications worked, Larsen said.

He was still in high school when he started working part-time at FlavorX, a private company then based in Bethesda that adds non-sweetened flavor to medicines to make them easier to consume. FlavorX gave him more lab and pharmaceutical experience.

Larsen proceeded to immerse himself in his studies over the next decade, earning three degrees, including a bachelor's in nursing from the University of Maryland in 2013. He worked at a pharmacy specializing in service for the elderly.

He always had a streak of self-reliance, fueled by his parents, who told him he would be on his own once he reached 18. That was the year Bandit died after a long decline.

Larsen could not find anything on the market to make his pup more comfortable, so he dedicated himself to finding something that would.

While working various jobs, he spent nights and weekends testing all kinds of formulas before developing a simple tabletop laboratory in his home in Laurel.

"It was a long road," he said. "I would come home at night and this was the big thing I would work on. I would run back and forth between my lab and my other job."

By January 2014, he had something. He partnered with FlavorX founder Kenny Kramm in RestoraPet while working full-time in nursing. Kramm died two years later, and Larsen bought out his interest.

Larsen is currently earning a master's in business administration from the University of Virginia Darden School of Business.

"I wanted to round out my business skills," he said.

It was a fellow Darden student - a servicemember working on his MBA - who helped Larsen connect with Meyerson. The Texan has a long history of hiring and supporting veterans and was coming off a failed attempt to get cannabis legalized in his state as treatment for post-traumatic stress disorder in the military.

"So I turned my attention to pets," Meyerson said. "I am a dog lover. I have had many dachshunds. I wanted something that had a chance of helping pets for anxiety and for arthritis as they get old. Once I decided that, I discovered what Brian was doing and it was a perfect fit.

"I met him. I liked him," Meyerson said of Larsen. "I put all this together and asked the question, 'If you had access to more capital, could you grow faster and do a better job?'"

Larsen answered yes.