McGowan was one of the first women to accuse the Hollywood producer of sexual misconduct and has since become a leading name of the #MeToo movement.
In October 2017, The New York Times published a report detailing decades of allegations against Weinstein. McGowan and fellow actor Ashley Judd were among the women to come forward.
In a new interview with The Guardian, the former Charmed star was asked what impact shaving her head prior to speaking out had.
“The side effect immediately was that people could hear the words coming out of my mouth, because I didn’t look like a traditional woman any more. All of a sudden, people were paying attention,” she said.
The 47-year-old continued: “But it was also like, ‘I’m serious. And I’m going to war. And I need to scare people. So let’s go.’”
In March last year, Weinstein was convicted of two counts of sexual assault and sentenced to 23 years in prison.
The actor was also asked whether she followed the allegations of bullying and harassment that were recently made against British director and actor Noel Clarke.
McGowan said she found the accusations “a bit shocking”. She added: “The thing is, for every one of those women, how many didn’t come forward? And did people know, and just were like, ‘This is how it is’?”.
Elsewhere in the interview, the actor also opened up about her decision to move from the US to Mexico.
“I just needed distance from stupid people, at the end of the day,” she said. “It’s very toxic [in the US]: the climate, the mental health. It is so sad.
“And I didn’t want to live so close to the enemy, if you will.”
If you have been raped or sexually assaulted, you can contact your nearest Rape Crisis organisation for specialist, independent and confidential support. For more information, visit their website here.