Testosterone’s role in physical development is significant and well understood, which makes the question of whether it increases height a reasonable one to ask. The relationship between testosterone and height is real — but it is also more complicated than a straightforward yes or no, and it changes fundamentally depending on age and whether the growth plates are still open.
The honest answer is that testosterone can support height increase during the right developmental window, but in adults whose growth plates have closed, it cannot add height and may under certain circumstances have the opposite effect.
Testosterone and Growth During Puberty
To understand how testosterone affects height, it helps to understand how height is determined in the first place. Bones grow at specialised regions near their ends called epiphyseal growth plates — or simply growth plates. These areas of cartilage allow long bones to lengthen during childhood and adolescence. Once they fuse and harden into bone at the end of puberty, no further height increase is possible regardless of hormone levels.
During puberty, testosterone plays a dual role in height. On one hand, it stimulates the release of growth hormone and IGF-1 (insulin-like growth factor 1), which drive the adolescent growth spurt. Boys typically experience their most rapid height gain in early to mid puberty — partly because of rising testosterone levels. This is the window in which testosterone genuinely supports increased height.
On the other hand, testosterone — and particularly its conversion to oestrogen via aromatase — is also responsible for eventually closing the growth plates. This is why boys who enter puberty earlier tend to be shorter in adulthood than those whose puberty is delayed: the early testosterone surge drives initial rapid growth, but also closes the growth plates sooner, limiting the total time available for growth.
What Happens to Height After the Growth Plates Close?
In most males, growth plates fuse fully between the ages of seventeen and twenty-five, with the majority completing fusion by their early twenties. Once this has happened, the structural capacity for height increase no longer exists. Bones cannot lengthen through hormonal stimulation once the growth plates are gone.
For adult men — including those considering or already on testosterone replacement therapy — testosterone does not increase height. It can influence body composition, muscle mass, fat distribution, and bone density, but it cannot reopen fused growth plates or cause long bones to lengthen.
Can Testosterone Therapy Affect Height in Any Way?
In adults with fully fused growth plates, TRT does not increase height. However, there are a few adjacent effects worth understanding:
Bone Density
Testosterone supports bone mineral density. Men with chronically low testosterone over years may experience some degree of bone thinning. TRT in this context can help preserve and in some cases partially restore bone density, but this affects the structural integrity of existing bone rather than its length.
Posture and Muscle Support
Low testosterone is associated with reduced muscle mass and core strength, which can contribute to postural changes — a slight forward rounding of the upper spine, for instance. Restoring testosterone levels through TRT, alongside exercise, may support better posture and a more upright stance. This is not an increase in skeletal height but can affect how tall someone appears and feels.
In Adolescents with Delayed Puberty
For boys with clinically diagnosed hypogonadism or significantly delayed puberty, carefully timed testosterone therapy under specialist supervision can support the growth spurt that would otherwise be stunted or delayed. The timing and dose are critical — testosterone given too early or in excess can accelerate growth plate closure and result in shorter adult height rather than taller.
The Risk of Exogenous Testosterone in Young Men
This is an important clinical point that is often overlooked in online discussions about testosterone and height. Young men — particularly teenagers and men in their early twenties — who use anabolic steroids or unsupervised testosterone to enhance performance or physique may actually compromise their final adult height if their growth plates have not yet fully fused. Supraphysiological levels of testosterone accelerate growth plate closure, potentially ending the growth window prematurely.
This is one of several reasons why testosterone use outside of medically supervised replacement therapy carries significant risk in younger men, and why clinical assessment of growth plate status is relevant when testosterone therapy is being considered in anyone under twenty-five.
What Testosterone Actually Does in Adult Men
For adult men whose growth plates are fully fused — which is the majority of men considering TRT — the benefits of testosterone replacement, when clinically indicated, relate to areas well beyond height:
- Energy and fatigue. Restoration of low testosterone often produces meaningful improvement in energy levels and reduction in persistent fatigue.
- Libido and sexual function. Testosterone is the primary hormonal driver of male sex drive, and low levels are a common and treatable cause of reduced libido.
- Muscle mass and body composition. Testosterone supports lean muscle retention and fat metabolism. Men on TRT typically find it easier to build and maintain muscle while reducing body fat.
- Mood and cognitive function. Low testosterone is associated with low mood, irritability, and difficulty concentrating. Restoration to normal levels often produces a noticeable improvement in these areas.
Frequently Asked Questions
- Can testosterone make you taller after puberty?
No. Once the growth plates have fused — typically by the early to mid twenties — no hormonal intervention can increase skeletal height. Testosterone does not reopen fused growth plates. In adults, TRT influences body composition, bone density, energy, and libido but has no effect on height.
- Does low testosterone make you shorter?
Low testosterone in adulthood does not directly reduce height, but it can contribute to reduced bone density over time and postural changes associated with muscle weakness. These effects can make someone appear or feel less upright, but they are not a reduction in skeletal height. TRT in men with confirmed low testosterone can help preserve bone density and support better posture and muscle mass.
- At what age do growth plates close in males?
Growth plates typically begin closing in mid to late adolescence and complete fusion in most males between the ages of seventeen and twenty-five. The exact timing varies between individuals and between different bones in the body. A bone age X-ray can determine whether growth plates are still open in cases where this is clinically relevant.
- Can anabolic steroids stunt growth in teenagers?
Yes. Supraphysiological levels of testosterone or anabolic steroids in teenagers whose growth plates have not yet fully fused can accelerate plate closure and reduce final adult height. This is one of the most significant risks of unsupervised anabolic steroid use in young men, alongside cardiovascular, hormonal, and psychological effects.
- How do I know if I have low testosterone?
The most reliable way is a blood test. Symptoms of low testosterone — fatigue, low libido, poor recovery, difficulty building muscle, low mood — are non-specific and can have other causes. A testosterone blood test at The Private GP in Birmingham provides an accurate baseline, with results discussed directly with a doctor who can advise on whether levels are clinically low and whether testosterone replacement therapy is appropriate.
Get Your Testosterone Assessed in Birmingham
If you have questions about testosterone and your health — whether related to energy, body composition, libido, or hormonal wellbeing — The Private GP in Birmingham offers same-day testosterone blood tests and GP consultations, with results reviewed and explained by a doctor rather than simply posted through the door.