Testosterone, a hormone that plays a role in the development of characteristics often associated with males, causes significant changes to the voice. These changes are particularly noticeable during puberty, but they can also occur in adulthood, especially when testosterone is introduced exogenously through hormone therapy. The hormone directly impacts the structures involved in voice production, leading to a lower pitch and a deeper vocal quality.
Testosterone’s Role in Vocal Cord Development
Testosterone primarily affects the larynx and the vocal cords within it. During male puberty, increased testosterone levels cause the laryngeal cartilage to enlarge, resulting in a more prominent Adam’s apple. This enlargement of the larynx is a key factor in voice deepening.
Vocal cords undergo substantial changes under the influence of testosterone. They become thicker and longer, which directly impacts their vibratory frequency. Thicker and longer vocal cords vibrate at a slower rate, producing a lower-pitched sound. This process is responsible for the significant drop in voice pitch observed during puberty.
The voice changes typically occur between 11 and 15 years of age and can take two to three years to stabilize, with full stabilization often achieved by age 17. During this period, individuals may experience a “voice break,” characterized by sudden, temporary shifts to a higher pitch or a cracking sound, as the brain adjusts to controlling the newly enlarged vocal structures.
Voice Changes in Adulthood
Testosterone administered in adulthood, such as in gender-affirming hormone therapy, leads to notable and generally permanent voice changes. These changes typically begin within weeks to months, with more pronounced shifts evident around three to six months. Most individuals experience a stabilization of vocal changes by 12 months.
The primary effect in adulthood is the thickening of the vocal cords, leading to a permanent lowering of voice pitch. While the vocal cords thicken, there is no consistent evidence that they lengthen significantly in adults. This means that while the voice will deepen, the extent of change can vary between individuals, and not everyone will achieve the same vocal depth. Once these vocal cord changes occur, they are permanent, and stopping testosterone therapy will not reverse the deepening of the voice.
Additional Influences on Voice
Beyond testosterone, various other factors can influence voice pitch, quality, and overall health. As people age, for example, both men and women experience changes in their vocal cords; in men over 65, a reduction in testosterone can contribute to vocal fold bowing and a higher perceived breathiness, sometimes leading to a higher fundamental frequency and a clearer tone.
Vocal habits, such as extensive singing or frequent yelling, can also shape voice characteristics over time. Lifestyle choices, including smoking, can negatively affect vocal cord health and quality. Certain medical conditions, such as thyroid disorders, or specific medications can also alter the larynx or vocal cords, leading to noticeable voice modifications.