Does Testosterone Cause Tendon Ruptures? What the Research Actually Shows
If you take testosterone replacement therapy and lift weights, you may have heard a concerning claim:
“Testosterone weakens your tendons and causes them to rupture.”
There is actually some research behind the concern.
Several large observational studies have found higher rates of certain tendon injuries among people prescribed testosterone, including injuries involving the Achilles tendon, distal biceps, rotator cuff and quadriceps tendon.
But that does NOT automatically mean testosterone directly damages otherwise healthy tendons.
And it definitely does not mean appropriately prescribed testosterone replacement therapy is biologically equivalent to high-dose anabolic steroid use.
The real story is considerably more interesting.
One possibility is that testosterone allows muscles to become stronger and capable of producing more force before the tendons transmitting that force have had enough time to fully adapt.
In other words:
Your muscles may get stronger faster than your tendons get stronger.
Let’s look at what the research actually shows.
First: What Does a Tendon Actually Do?
A tendon connects muscle to bone.
When your biceps contracts, your distal biceps tendon helps transmit that force to your forearm.
When you jump, sprint or perform a heavy calf raise, the Achilles tendon transmits enormous amounts of force between your calf muscles and your heel.
Tendons are not simply ropes connecting muscles to bones.
They are living tissues that respond to mechanical loading. Resistance training can increase tendon stiffness, alter its material properties and, over time, increase tendon cross-sectional area. But these adaptations develop over weeks and months of appropriately progressed loading. Systematic reviews suggest meaningful tendon adaptation generally requires sustained exposure to sufficiently high mechanical loading rather than occurring overnight.
This distinction becomes important when muscle strength begins increasing rapidly.
What Have Studies Found in Men Taking Testosterone?
Several recent studies have investigated prescription testosterone and tendon injuries.
These studies are worth taking seriously.
They also have important limitations.
Distal Biceps Tendon Injuries
A 2023 retrospective study examined people aged 35 to 75 who had filled testosterone prescriptions for at least three consecutive months.
After matching 291,610 testosterone users with 291,610 controls, researchers identified:
650 distal biceps injuries in the testosterone group
159 injuries in the control group
That works out to approximately:
0.22% versus 0.05% during the first year.
The reported odds ratio was 4.10 during that period.
Over longer follow-up, the association became smaller, although testosterone exposure remained associated with increased distal biceps injury.
That sounds dramatic when expressed as a relative increase.
But notice the absolute numbers.
Most people in both groups did not rupture their biceps tendon.
That distinction between relative and absolute risk matters whenever we interpret medical studies.
Testosterone and Achilles Tendon Injuries
Another study examined more than 423,000 people prescribed testosterone and matched them with controls.
The incidence of Achilles tendon injury was approximately:
378 injuries per 100,000 person-years in testosterone users
versus
246 injuries per 100,000 person-years in controls.
After adjustment, testosterone exposure was associated with approximately 24% greater odds of an Achilles tendon injury.
Among people who developed an Achilles injury, surgery was also somewhat more common in the testosterone group.
The authors calculated an overall number needed to harm of approximately 371.
Again:
There appears to be a signal.
But this is very different from saying that testosterone commonly causes Achilles ruptures.
What About the Rotator Cuff and Other Tendons?
Similar associations have been reported elsewhere.
A retrospective rotator cuff study found testosterone users had higher rates of rotator cuff tears and subsequent repair procedures.
Another analysis found increased odds of quadriceps tendon injury among patients prescribed testosterone.
And broader analyses have now reported increased rates of tendon tears across multiple anatomical locations among testosterone users. One study specifically examined people who began testosterone despite lacking documented laboratory evidence meeting commonly used criteria for testosterone deficiency and found increased odds of tendon tears during subsequent follow-up.
Most recently, a 2026 retrospective analysis again reported increased tendon-tear rates among testosterone users.
When multiple databases begin finding similar associations, we shouldn’t simply ignore them.
BUT we also shouldn’t turn an association into causation.
Here’s the Biggest Problem With These Studies
Most of these studies use enormous insurance-claims databases.
That’s useful because researchers can analyze hundreds of thousands of patients.
But claims databases are very good at answering questions such as:
Was this person prescribed testosterone?
and
Was this person later diagnosed with a tendon injury?
They are much WORSE at answering the question we actually care about:
Why did the tendon rupture?
The databases generally cannot adequately tell us:
How much the patient exercised
Whether he lifted weights
Whether he recently returned to training
How quickly his strength increased
Whether training volume suddenly doubled
Whether he was sprinting, jumping or playing recreational sports
Whether he already had chronic tendinopathy
His actual testosterone concentration while being treated
Whether his testosterone level became physiologic or supraphysiologic
The exact testosterone dose or exposure over time
Whether he used additional anabolic steroids that were never documented
That is an enormous amount of missing information.
And it leads us to one of the most interesting explanations for the association.
The Muscle-Tendon Mismatch
Imagine a 45-year-old man who hasn’t trained consistently for several years.
His testosterone is low.
His energy is poor.
He’s lost muscle.
He starts appropriately indicated testosterone replacement therapy.
Within several months:
He feels better.
He trains consistently again.
He gains muscle.
His bench press increases.
His deadlift increases.
His squat increases.
His motivation increases.
And he starts lifting weights he hasn’t touched in 10 years.
That’s great.
But there is one problem:
His tendons didn’t suddenly become 25 years old again.
Muscle and tendon both adapt to resistance training, but they do not necessarily adapt at identical rates.
Tendon remodeling requires sustained mechanical loading. Research examining healthy tendon adaptation suggests meaningful changes in mechanical properties often develop over training periods extending beyond 12 weeks.
So it is biologically plausible that muscle strength and force-generating capacity can increase faster than the tendon has remodeled sufficiently to accommodate a rapidly escalating training load.
Think of it like installing a more powerful engine.
The engine may suddenly produce much more power.
But you still need the drivetrain, transmission and tires to tolerate it.
That doesn’t prove testosterone caused the tendon injury.
It suggests that rapidly increasing force applied to an inadequately adapted tendon may be part of the equation.
Does Testosterone Directly Damage Tendons?
This is where we have to be careful.
There are biological reasons to investigate this question.
Experimental studies, particularly involving supraphysiologic anabolic-androgenic steroids, have demonstrated alterations in collagen metabolism, extracellular matrix remodeling and tendon mechanical properties.
But much of that evidence involves either:
animal models, or
anabolic steroid exposures that are very different from physiologic testosterone replacement.
We cannot automatically translate those findings to a man whose testosterone is being restored from a deficient level into a physiologic range.
Human research involving long-term anabolic steroid users is interesting.
One study comparing trained steroid users with resistance-trained nonusers found that the patellar tendons of steroid users had approximately:
26% greater stiffness
30% greater Young’s modulus
15% greater maximal tendon stress
The researchers concluded that long-term anabolic steroid use appeared to produce different tendon adaptations and collagen remodeling compared with resistance training alone.
Notice what that study did not demonstrate.
It did not simply show that steroids made tendons “weak.”
Tendon biology is more complicated than that.
The concern may involve abnormal remodeling, altered stiffness, greater stress and potentially a reduced mechanical safety margin.
TRT and Anabolic Steroid Abuse Are Not the Same Thing
This distinction gets lost constantly.
Testosterone is technically an anabolic-androgenic steroid.
But medically prescribed TRT intended to restore physiologic testosterone levels is not equivalent to supraphysiologic bodybuilding drug regimens.
And the tendon data involving long-term anabolic steroid users are considerably more striking.
Researchers studied 142 experienced male bodybuilders aged 35 to 55.
Among the 88 men reporting at least two years of cumulative anabolic steroid use:
19 — approximately 22% — had experienced at least one tendon rupture.
Among the 54 nonusers:
3 — approximately 6% — had experienced a rupture.
The reported hazard ratio for a first tendon rupture among steroid users was 9.0.
Even more interesting:
Upper-body tendon ruptures occurred in 17% of anabolic steroid users and none of the nonusers in that cohort.
That is a significant signal.
But it would be inappropriate to tell a man using physiologic TRT that he therefore has a ninefold tendon-rupture risk.
He doesn’t.
These are completely different exposures.
Two Mechanisms Could Potentially Be Happening
The evidence leaves us with two possibilities that are not mutually exclusive.
1. Muscle Strength May Increase Faster Than Tendon Capacity
Testosterone can increase lean mass and strength, particularly in testosterone-deficient men when therapy is combined with resistance training.
If strength and training intensity rise rapidly while tendon remodeling lags behind, more force may be transmitted through a structure that hasn’t completely adapted to that new loading environment.
This is particularly relevant for men returning to heavy training after years away from the gym.
2. Very High Androgen Exposure May Directly Alter Tendon Remodeling
Supraphysiologic anabolic steroid exposure may also have direct effects on collagen metabolism and tendon mechanical properties.
Human and animal data make that biologically plausible.
But we have much less evidence demonstrating clinically significant direct tendon toxicity from properly managed physiologic TRT.
Those two categories should not be conflated.
Your Muscle Feeling Stronger Doesn’t Mean Your Tendon Is Ready
This may be the most important practical takeaway.
Suppose you start TRT.
Three months later you feel fantastic.
Your energy is better.
You’ve gained lean mass.
Your lifts are rapidly climbing.
That’s not the time to conclude:
“I feel 25 again, so I’m going to train exactly like I’m 25 again.”
Muscles are extraordinarily responsive tissues.
Tendons adapt too, but they require progressively applied mechanical stress.
The solution isn’t to avoid resistance training.
Actually, appropriate resistance training is one of the best ways we know to stimulate positive tendon adaptation.
The solution is progressive loading.
How Should Men on TRT Train?
For most men using medically appropriate TRT, the tendon data should not be interpreted as a reason to stop exercising.
Quite the opposite.
Resistance training remains incredibly important for muscle mass, metabolic health, bone health, physical function and healthy aging.
But there are some common-sense principles worth following.
Progress your load instead of chasing immediate PRs
Feeling stronger doesn’t mean you need to test maximal strength every week.
Allow your training volume and intensity to increase gradually.
Don’t ignore chronic tendon pain
A chronically painful Achilles, patellar tendon, elbow or shoulder deserves attention before aggressive loading continues.
Tendinopathy often precedes rupture.
Be particularly careful when returning after a long layoff
The 40- or 50-year-old who hasn’t trained seriously for several years may be especially vulnerable to doing too much too quickly when energy and strength return.
Remember that connective tissue needs training too
Tendons respond to resistance exercise.
Give them the time and progressive loading necessary to do it.
Don’t confuse physiologic replacement with bodybuilding doses
The higher-dose anabolic steroid literature should reinforce why pushing androgen exposure far beyond physiologic levels carries risks that cannot simply be extrapolated from normal testosterone replacement.
So Does TRT Cause Tendon Ruptures?
Here is where the evidence currently leaves us:
Prescription testosterone has repeatedly been associated with increased rates of several tendon injuries in observational studies.
That signal is real enough that clinicians and patients should know about it.
However:
Those studies do not prove that testosterone directly causes tendon rupture.
Important confounding variables — especially resistance training, changes in strength, training volume, tendon health and undocumented anabolic steroid use — are largely missing.
Meanwhile, the relationship between supraphysiologic anabolic steroid exposure and tendon rupture appears considerably stronger.
A plausible explanation is that increasing muscle strength, activity and mechanical loading can expose tendons to greater forces before connective tissue has fully adapted.
Direct effects of very high androgen exposure on tendon remodeling may also contribute.
The evidence simply does not support reducing all of that complexity to:
“TRT destroys tendons.”
The Bottom Line
If testosterone replacement therapy is medically appropriate, fear of tendon rupture alone shouldn’t automatically keep a man from treating testosterone deficiency or resistance training.
But testosterone doesn’t make every tissue in your body instantly younger.
When you start feeling stronger, train intelligently.
Build muscle.
Get stronger.
Progress your loads.
But give your connective tissue time to come along for the ride.
Your muscles may feel younger before your tendons do.
That is probably the lesson worth remembering.
At Fit & Fine Health, testosterone optimization isn’t simply about writing a testosterone prescription.
Men’s health requires looking at hormones, body composition, metabolic health, cardiovascular risk, sleep, sexual health, nutrition, training and long-term performance together.
If you’re experiencing symptoms of low testosterone — or you’re already taking TRT but want a more comprehensive approach to monitoring and optimizing your health — you can start with a complete men’s health assessment and laboratory evaluation.
Start with the data. Understand the whole picture. Then build the right plan.
David Hall, MD, CWC
Board-Certified Urologist
Founder, Fit & Fine Health
Medical Disclaimer:
This content is for educational and informational purposes only and is not intended to provide medical advice, establish a physician-patient relationship, or replace individualized evaluation by a qualified healthcare professional. Testosterone therapy, exercise recommendations, and decisions related to tendon injuries should be based on a patient’s medical history, examination, laboratory findings, medications, training history, and individual risk factors. If you develop sudden pain, weakness, bruising, deformity, or loss of function concerning for a tendon rupture, seek prompt medical evaluation.