Triggered by hormonal changes in the brain and body, puberty marks a physical transformation. Oestrogen and testosterone – often called “sex hormones” – drive many familiar changes, such as breast development and periods or a deeper voice and facial hair.
For most young people, the pubertal changes they experience align with their gender. However, for trans and gender diverse adolescents, these changes can be distressing and may lead to a sense of disconnection from their true sense of self.
(We’ll use the term “trans” in this article to refer to transgender and gender diverse people.)
Why do young trans people use sex hormones?
To support trans adolescents, oestrogen and testosterone may be used to induce physical changes that better align with their gender.
Oestrogen stimulates breast development, alters body fat distribution, results in softer skin, and reduces facial and body hair, creating a more feminine appearance.
Testosterone deepens the voice, increases facial and body hair, promotes muscle growth and stops periods, creating a more masculine appearance.
Hormones are just one means by which people can affirm their gender and only some trans adolescents seek sex hormone treatment. Other means include puberty suppression, changing your name, pronouns, hair, clothing and legal documents.
When do trans people start sex hormones?
Many trans people start taking sex hormones as adults.
For those who start as adolescents, hormones are introduced when a young person is considered to have the intellectual and emotional maturity to make this decision.
The starting age also varies depending on the person’s preferences, family support and barriers to accessing care. These barriers include long wait times, regional disparities, costs, legal or policy restrictions, and challenges navigating the health system, all of which make it harder to get timely, reliable care.
Before starting hormone therapy, trans adolescents undergocomprehensive assessment and counselling with a team of mental health professionals and medical doctors who specialise in transgender health. This helps ensure young people understand the potential benefits, limitations, risks, and long-term implications of treatment.
This process involves their family and is designed to provide time, support and space for shared, informed decision-making.
Treatment with sex hormones usually begins with low doses, after which adjustments are made over time under regular clinical monitoring.
Subsequent physical changes occur gradually over several years, as is true for puberty, and some of these are irreversible. Breast growth or a deepened voice, for example, will persist if treatment is stopped.