Having served a doping ban between October 2013 and February 2015, Efimova tested positive for meldonium earlier this year, only for her provisional suspension to be overturned by the sport's governing body, clearing her to compete in Rio.
Booed when she took to the pool, Efimova drew the ire of American Lilly King, who labeled her rival a drug cheat after the two clashed during the women's 100-meter breaststroke event.
And after beating Efimova to the gold, King had more harsh words. This time, King was backed up by Michael Phelps, who commended his fellow American for speaking out on the subject.
Despite the hostilities with Team USA athletes, Efimova plans to return to her Los Angeles home. The 24-year-old has lived in the US for the last five years.
"Life is so much easier than in Russia," Efimova, who won two silver medals in Rio, told CNN's Nick Paton-Walsh. "Everybody is smiling."
"America is about change," she said. "It changed me."
Rio was Efimova's third Olympics. King is five years her junior, taking two gold medals home from her first Games.
Efimova suggested at this point in her career King's lacks the experience to fully understand the Russian's position.
"She is too young," said Efimova. "She is too young. She (doesn't) know about things. She (doesn't) know how life is going sometimes when you try to do right."
The Russian doping scandal overshadowed the buildup to these Olympics. The IAAF, the body that governs international track and field, took the decision to ban all of its athletes from competing.
An independent report commissioned by the World Anti-Doping Agency (WADA) alleged state-sponsored doping in the country, with the federations in charge of each individual sport deciding on whether athletes would be able to compete in Rio.
Efimova found out she could take part in the Games the day only after the Opening Ceremonies had taken place.
Subsequently, Russia's athletes have been frequently heckled at a number of events.
"I don't want to believe this," Efimova said regarding the findings of the report by Canadian Richard McLaren.
"It's more stupid (to suggest) Russian can use doping and everyone else is fine," continued Efimova.
Asked whether she thought the report was politically motivated, Efimova said yes.
"It's like Russia, Russia, Russia, Russia like all Russia -- drink vodka, like have beer and drink doping and that's it."
On a personal level, the negativity has taken its toll.
Efimova admitted that at times she has wanted to give up; the support of her friends and family convince her to keep going. She said: "If I would be just by myself, I am pretty sure I (would) not seated here..."
And Efimova's experiences at Rio have led to sleepless nights.
"It's not only one night, trust me, like last three weeks I sleep for four-three hours a day."