Born in Barcelona in 1966, Forcades grew up in a home where her parents rejected religion. She was sent, however, to the private Sacred Heart school, where she discovered religious faith through the study of the Bible given by the religious sisters who ran the school. She went on to study medicine at the University of Barcelona. In 1992 she moved to the United States, where in 1995 she completed a residency at the University of Buffalo School of Medicine, specializing in internal medicine. After obtaining a scholarship, she moved to Cambridge, Massachusetts, where she gained the degree of Master of Divinity from the Harvard Divinity School in 1997.
As the result of a stay in order to prepare for some examinations which Forcades made at the Monastery of St. Benedict in Montserrat, Spain, founded in 1952, and connected to the famed Abbey of Santa Maria de Montserrat, she felt a call to monastic life. In September 1997, she entered the monastery, where she follows the Benedictine pattern of life, while still working in the fields of religious study, theology and medicine. In 2004 she obtained a doctorate in public health from the University of Barcelona. In 2005 she obtained a degree in theology. After four years, in 2009 she received a doctorate from the School of Theology of Catalonia.
Teresa Forcades understands feminism as a form of liberation theology. She believes, in accordance with the Catholic Church's position, that a fetus has a right to life, but she also believes, contradicting the Catholic Church's position, that a pregnant woman has a right to self-determination that is equally absolute. In that sense, she has publicly supported abortion and the distribution of the morning-after pill.
The Vatican has criticised her activism and in 2009, Cardinal Franc Rodé, C.M., Prefect of the Congregation for Institutes of Consecrated Life and Societies of Apostolic Life, requested of Forcades' abbess that she be ordered to express publicly her commitment to the official teachings of the Catholic Church. In response, she issued an article in which she reaffirmed her respect for the official teaching authority of the Catholic Church (the Magisterium), but also indicated that she was free to disagree publicly, and she repeated her support of a woman's right to self-determination in the matter of abortion.
Forcades has openly criticised the Catholic church as "misogynist and patriarchal in its structure". She has developed her thoughts on this in the light of liberation theology.
During the height of the swine flu pandemic, Forcades said that the flu vaccine was rushed into research and production, and lacked proper scientific basis for public use. She published an hour-long video on YouTube on history of type A flu, political context of pandemic and irregularities related to the H1N1 vaccine.
She has been fiercely criticised for her positions, specifically her support of MMS, a version of industrial strength bleach, which she says can cure a wide range of illnesses, including cancer, malaria, HIV, acne and hepatitis.
An article in El País labelling her as a "paranoid conspiracist" and "hoaxer-nun". produced a stream of complaints from readers and had later its objectivity and quality put into question by the newspaper's Public editor.
In 2013, Forcades co-authored the Manifesto for the convening of a constituent process in Catalonia, with economist Arcadi Oliveres. In it they proposed achieving independence for Catalonia through new political and social model based on self-organization and social mobilization. Her political activism resulted in The Guardian labelling her as "one of the most outspoken [..] leaders of southern Europe's [...] far left".
In 2015, as another major vote for Catalan independence approached, Forcades received permission from her superior and the Holy See to set aside her habit and don secular attire, entering the political arena to lead the leftist Procés Constituent movement. She remarked, "Criticisms are to be expected. I follow somebody called Jesus and he had a lot of that."
Forcades has written three books:La Trinitat avui (The Trinity Today) (Publicacions de l’Abadia de Montserrat, 2005)
Els crims de les grans companies farmacèutiques (The Crimes of big Pharmaceutical Companies) (Cristianisme i Justícia, 2006)
La teologia feminista en la història (Feminist Theology in History) (Fragmenta Editorial, 2007)