Steven Marrocco

USA TODAY Sports

Dan Henderson was the first%2C and likely last UFC fighter to legally use testosterone replacement therapy

Sunday%27s fight in Brazil will likely be his last time using TRT legally

Henderson will fight Mauricio %22Shogun%22 Rua at Fight Night 38

Ultimate Fighting Championship light heavyweight Dan Henderson was the first mixed martial artist to legally use testosterone-replacement therapy, and he might be the last.

The UFC's ban on the treatment takes effect after Henderson's rematch with Mauricio "Shogun" Rua, which headlines UFC Fight Night 38 on Sunday in Natal, Rio Grande do Norte, Brazil (5 p.m. ET, Fox Sports 1).

Although Henderson's name bookends a list of TRT users in a controversial epoch for the sport, he said his longevity won't be defined by testosterone.

"It's business as usual," Henderson, who was first approved for TRT in 2007, tells USA TODAY Sports. "I'll deal with the changes after this fight. Obviously, I'll have to."

Henderson, 43, believes the UFC's ban on TRT misses a bigger issue of performance-enhancing drug abuse and said random drug testing would be more effective. But he'll explore alternatives for the treatment as he nears 17 years as a professional fighter.

"I don't think TRT has anything to do with my skills as a fighter," he says. "I think I get sick a little bit less and have a little more energy. I don't lay on the couch as much when I'm on TRT, but it's not the reason I've done as well as I've done in the sport."

Jeffrey Brown, a Texas-based endocrinologist who's treated dozens of professional athletes, says there are alternatives for TRT, such as human chorionic gonadotropin and clomiphene citrate. But they are on the World Anti-Doping Agency's list of banned substances, and for Henderson, they "would take a long time to work in a person who has been on TRT that long."

Henderson, though, will keep fighting even if he can't find a suitable alternative.

Storylines from Fight Night 38

"I have no plans of retiring at all," he says. "I just signed a six-fight deal, and I plan on achieving my goals within those six fights."

A former two-division champion in PRIDE and a two-time UFC title challenger, Henderson's push for a UFC belt hit a major snag in 2013; he dropped three consecutive bouts and was knocked out for the first time in a rematch with Vitor Belfort, who also will have to fight TRT-free.

Some have speculated that the UFC might force Henderson to retire with a fourth loss, but Henderson, who took a salary cut when he re-signed, says the promotion knows he's a draw and will keep him in the fold.

If anything, UFC execs are hoping he can recreate the fireworks of his first bout with Rua (22-8, 6-6), at UFC 139 in 2011, the last time Henderson won.

Henderson wrote off his recent knockout loss as a tactical mistake and said he simply needs to balance aggression with smart execution inside the cage.

"Hopefully, this next year will be a good year," he says. "I had a bad year last year, and I'm just moving forward."

Marrocco writes for MMAJunkie