You’ve been feeling better for a few weeks since starting TRT. Less tired, more energy, your libido is back. And then, one ordinary morning, you notice something else: there’s more hair in the shower drain than you’re used to.
Is it due to the therapy, or is something else at play? The honest answer is that it can be, but not for everyone, and not for the reason most men expect.
What TRT actually does
Testosterone Replacement Therapy is prescribed when blood tests show that your testosterone levels are consistently too low. This is called hypogonadism. In the Netherlands, treatment is conducted under medical supervision, using a gel, an injection, a patch, or sometimes an implant. The number of men seeking this treatment at clinics has grown significantly in recent years: low energy, decreased libido, and a depressed mood are no longer automatically dismissed as “just getting older.”
The difference from an anabolic steroid cycle is that TRT replenishes a deficiency rather than creating an excess. For your hormone balance, this is a fundamental difference. For your hair, that difference turns out to be much smaller in practice than you might wish.
Why your DHT increases
Part of the testosterone you receive through TRT is converted into DHT by the enzyme 5-alpha-reductase. This is the same hormone that slowly causes hair follicles to shrink in cases of hereditary hair loss. When you start TRT, your DHT level almost automatically increases with it, in some cases up to two or three times the level before treatment.
How much it increases depends partly on how it is administered. A gel applied daily to the skin often causes a higher peak than an injection, simply because absorption through the skin is different. Long-acting injections and implants usually result in a flatter curve. You should discuss which form is best for you with your doctor. This is not something you should try to figure out on a forum yourself.
How many men are truly affected
Research figures vary widely. Some studies report that between 5 and 17 percent of men develop noticeable hair loss in the first year of TRT. Other sources cite much higher percentages, up to about 40 percent. This difference says less about how risky TRT is, and more about how inconsistently such research is designed and how differently "noticeable hair loss" is actually defined.
What most studies do agree on: it's not the majority of men who experience it. A large proportion notice little to no change in their hair, even after years of therapy.
Why it happens to some and not to others
The increase in DHT is fairly similar for most men on TRT. The difference lies in how your hair follicles react to it. If you don't have a genetic sensitivity to DHT, your follicles will barely react to that higher level. If you do have that sensitivity (often recognizable by hair loss in your father, grandfather, or brothers), TRT might accelerate something that was already going to happen anyway.
In this way, TRT rarely causes hair loss in someone who would never have been susceptible to it. It mainly accelerates a process that was already underway, just below the surface. No reason to ignore the side effect, but it helps to know where your risk comes from before panicking over a few extra hairs in the shower.
How to distinguish it from normal shedding
Not every change in your hair during TRT is due to DHT. Stress, a busy period, or simply your body adjusting to a new hormone level can temporarily cause more hair loss all over your head, instead of in the areas where hereditary baldness usually begins. This is called telogen effluvium and usually resolves within a few months.
If you mainly see a receding hairline or a thinning crown, that points more towards DHT. If your hair feels thinner all over your head without a clear pattern, it's more likely to be temporary. A few photos from the same angle, every few months, will tell you more than your feeling in the mirror that morning.
What you can do if you've already started
If you doubt whether your hair loss is due to TRT, discuss it with the doctor supervising the treatment, not with a forum. Blood values, including your DHT level, provide a fairer picture than how much hair you think you see.
A different method of administration can help if DHT peaks are the cause. Some doctors also periodically measure your DHT, not just your total testosterone. In consultation, a DHT blocker like finasteride may be an option, although this is not a decision you make yourself: finasteride can also affect how you feel during TRT, and you make that decision together with a doctor.
There's also an approach that has nothing to do with your hormones. A serum with ingredients like Redensyl or Procapil doesn't interfere with DHT, but improves the environment around the hair follicle so it stays active longer. The Hairborn Growth Serum doesn't fully compensate for the DHT increase from TRT, but it can make the difference between noticeably thinner hair and a hairline that remains fairly stable. Expect at least three to four months of daily use before you can say anything about it. Hair growth is slow, with or without TRT.
Is stopping a solution?
With an anabolic steroid cycle, you might consider stopping as soon as you notice hair loss. With TRT, it's different. If you're following therapy due to a confirmed deficiency, it's supplementing something that was already present even without treatment. Stopping usually means that the symptoms you started with, such as fatigue and low libido, will simply return.
A doctor can discuss a lower dose, a different administration method, or a DHT blocker with you, before you consider stopping something you started for a good reason.
In short
Most men on TRT do not go bald. Those who are sensitive to DHT usually see a process that was coming anyway, just a little faster than without the therapy. That distinction determines what a sensible next step is.
Early intervention offers the most options. This could be a conversation with your doctor about your administration method or a DHT blocker, or a serum that supports the hair follicles themselves without affecting your hormones. Waiting until the crown is clearly visible makes adjusting afterwards a very difficult task.
Frequently asked questions
Can you get a blood test to see how much your DHT is increasing?
Yes, a doctor can measure both your total testosterone and specifically your DHT level through blood tests, which provides a more precise picture than just looking at how much hair you're losing.
Is there a difference in risk between TRT with gel and with injections?
Yes, gels often cause a sharper, short-lived peak in DHT due to the way they are absorbed through the skin, while long-acting injections generally provide a flatter curve. This can play a role in how noticeable the effect on sensitive hair follicles is.
Can TRT be combined with a derma roller without additional risk?
Yes, a dermaroller works locally and mechanically on the scalp and has no known interaction with the hormonal effects of TRT, so you can use both alongside each other.
Does the risk change if you've been using TRT for years?
The risk seems to be most visible primarily in the initial period after starting, as this is when the DHT level increases most significantly compared to your baseline. With long-term, stable use, the risk generally doesn't change much more.
Can you request a lower dose specifically to limit hair loss?
Yes, that can be a topic of discussion with your doctor, although a lower dose must remain balanced with the goal of the treatment, which is to address your testosterone deficiency.
Is there a difference in risk between starting TRT young and old?
There is no strong evidence that age at the start of TRT itself determines the risk of hair loss; it primarily depends on your underlying genetic sensitivity to DHT, regardless of the age you start.
Can you tell from other body changes if you are sensitive?
Not reliably; other body changes during TRT say little about the specific sensitivity of your scalp follicles to DHT. Family history of hair loss remains the most useful indicator.
Does TRT affect your beard growth in the same way as your scalp hair?
No, DHT actually has a stimulating effect on beard growth and body hair, while it can have the opposite effect on sensitive scalp follicles. This difference lies in how different follicles on the body react to DHT.
Can you start finasteride preventatively before starting TRT?
That is a choice you make together with your doctor, as finasteride inhibits DHT production and this may also affect the desired effects of TRT. Preventative initiation is not standard without first discussing the individual risk.
Is hair loss a reason to switch to a different therapy?
Not necessarily; usually, adjustments within the same therapy, such as a different administration method or dose, are considered first before a completely different type of treatment for low testosterone is considered.
