Low Testosterone


Low T occurs when there's a hormone reduction in the body. Many of the symptoms such as erectile dysfunction, decreased energy, libido, and ability to build muscle or lose weight, are often caused by a drop in testosterone.
Although generally related to aging, Low T can occur in younger men in their 30's or 40's as well. Treating your Low T can dramatically change your life, but only if it's treated by a specialist who will monitor and calibrate your treatment over time.

An important issue that both clinicians and patients face is determining the best definition of Low T in younger men.

How does Maze define Low T and decide if treatment is appropriate?

We have always felt that symptoms were more important than numbers. If a man has classic symptoms of a low testosterone, our strong bias is to treat. If we use only the definition of a low testosterone as one below 300 ng/Dl, many men with low testosterone for their age with symptoms will be denied treatment.

In our practice, symptomatic men in the lowest third of their age range would be considered candidates for treatment. Assess your symptoms by taking our Low T Symptoms Quiz.

What are the average testosterone levels in younger men?

A recent study published in The Journal of Urology showed that the mean total testosterone of men 20-44 years old was 466 ng/dL.

The study’s definition of a low testosterone was defined by the group of men who were in the lowest third (or “tertile”) in terms of levels.

The study found that the middle tertile (third of men), “normal” testosterone levels were:
409-558 ng/dL (20-24 years old),
413-575 ng/dL (25-29 years old),
359-498 ng/dL (30-34 years old),
352-478 ng/dL (35-39 years old), and
350-473 ng/dL (40-44 years old).

Thus, the age specific cut-offs for having a testosterone in the lowest third of men for each age group would be:

409 ng/dL (20-24 years old),
413 ng/dL (25-29 years old),
359 ng/dL (30-34 years old),
352 ng/dL (35-39 years old), and
350 ng/dL (40-44 years old).

These are not absolute cut-offs in any particular man but indicate that younger men would be expected to have significantly higher levels on average; they also may become symptomatic with a higher level than in symptomatic older men.

How should testosterone levels be measured?

Low testosterone must be diagnosed by a medical professional who will conduct blood work to measure hormone levels. Many diseases and conditions may share symptoms and a medical professional who specializes in low testosterone will be able to identify the issue and create a treatment protocol. The doctor will interpret medical test results in conjunction with your physical symptoms.

If you have significant symptoms, consistent with a low testosterone, but have a normal testosterone, we will try to figure out what could be causing these symptoms. (i.e. Diabetes is one possibility.) If we can’t help you address them, we will refer you to the appropriate specialist(s). With our team approach, we have been able to help most men, many of whom do not need an outside referral.

Testosterone (T) Testing
There are several aspects of testosterone that make both testing and interpretation difficult:

Diurnal Variability
A man’s testosterone production, and thus blood levels, are not consistent throughout the day. In general, testosterone levels are higher in the morning and then decrease throughout the day. This variability is more pronounced in younger men and decreases as we age. In other words, for younger men it makes more of a difference what time their testosterone is measured than it does in older men.

For men under 45 years old, it is suggested that testosterone levels be measured before 10 AM. In our practice, we screen men at their first visit, no matter what the time. If the testosterone is borderline or low, we repeat it prior to 10 AM.

In men older than 45, there is significant debate as to how important it is to measure the testosterone level in the morning. Thus, we are not as concerned about what time the blood is drawn with this age group.

Overall Variability
There is a lot of variability in a man’s testosterone levels. The same man, or an older man, can have quite different testosterone levels throughout the day or at the same time of day on different days. Thus, the diagnosis is never made based on only one testosterone level measurement. If the second test is significantly different from the first test, a third may need to be performed. We have had many patients, with significant symptoms, whose first testosterone was “low-normal”, whose repeat testosterone was quite low and whose third test confirmed that it was, in fact, quite low.

Changes With Age and Differences Between Individuals
For all men, testosterone levels decrease with age. Again, every man is different, but it is thought that, for most men, this decrease may start as young as 25!

Many men with a “low-normal” testosterone level will ask, “How do I know what my levels were when I was younger? Maybe this is quite low for me!” There is a certain legitimacy to this. These men may indeed feel much better and more like themselves with a higher testosterone. Thus, we are always using a combination of blood work results and the clinical situation to make the decision as to whom to treat and how high their levels should go.

Why Do There Seem to Be So Many Different Testosterone Measurements?
When reading about testosterone, you will see various measurements referred to. These include:

-Total Testosterone
-Free Testosterone
-Bio-available Testosterone
-Free Androgen Index

The most important thing to realize is that the Total Testosterone measures all of the testosterone that is in your blood stream. However, most of that testosterone is bound to proteins. Any testosterone that is bound forms a complex that is too big to get out of your blood stream. Thus, it is not free to go into the cells themselves, and is not useful to your body. You will not benefit from it. The most important of these proteins is Serum Hormone Binding Complex (SHBG.) SHBG binds tightly to testosterone, and takes it out of commission. Thus, if you have a low normal testosterone but high SHBG, the amount of testosterone your body can use is low.

SHBG levels increase as men age. Men with liver issues or on chronic opioids will have high SHBG. Men with high female hormones or thyroid issues may also have an increased SHBG. Some men without any known risk factors have high SHBG.

Traditionally, these men are under-diagnosed and under-treated. In order to diagnose these men, a testosterone measurement that takes into account SHBG must be performed.

Are Different Labs Different When it Comes to Measuring Testosterone?
Studies have shown that there is a huge variation in results from lab to lab specifically when dealing with testosterone. Not only do different labs perform different testosterone measurements (i.e. free testosterone versus free androgen index), they do it in different ways. It is important to have a specialty laboratory, such as Maze Labs, test the hormones and to use the same laboratory every time the blood is tested. Once you have begun treatment, you will want to know not only where your levels currently are, but how those levels relate to where you started!

What Constitutes a Low Testosterone Level?
There remains significant controversy as to what represents a “low“ testosterone level. It is well accepted that a man with symptoms and two testosterone levels below 300 ng/dl (nannograms per deciliter) has a low testosterone and should be considered for treatment. The far more complicated question comes with regards to what constitutes a “normal” testosterone level.

What does “normal testosterone level” mean?
First of all, it is important to understand what “normal level” means in the context of any lab value. Traditionally, this means that your levels fall within the range for 95% of men. If your levels are abnormal, then you are in either the lowest 2.5% or the highest 2.5% of all men. This means that in order for your testosterone to be reported as “low”, you must test lower than 39 out of 40 men.

“Normal” is also different than “optimal.” For example, we do not want men to have a “normal” cholesterol. We want them to be in a range where they are least likely to have cardiovascular events. “Normal” is not our goal, “optimal” is!

Separately, there is another issue with “normal” levels that have been determined, as mentioned above, by seeing where the range within which 95% of men fall. These levels are not stratified by age! We know that as men age, testosterone decreases dramatically. However, this is not taken into account when looking at the reference ranges. Should a 30 year old man have the same estimation of “normal” as a 75 year old man? Obviously, not.

For example, in one large study, the mean testosterone for men 25-29 was 669. However, even more importantly than the mean, is where does a certain level put you compared to other men in your age cohort? For men aged 25-29, if your testosterone is 438 or less, you fall in the lowest 10% of men for your age group. If your testosterone is 388 or less, you fall in the lowest 5% of men in your age group. It would make sense that you may not feel great, even if your testosterone level is “normal” by standard criterion which considers any level of over 300 as normal. Should a symptomatic 27 year old man with an average testosterone level, using morning readings of less than 425 be treated? We think yes, and our experience has borne this out.

Is my testosterone low for me? Some of the things we simply don’t know:
Most men do not have their baseline testosterone levels measured. They are usually only measured once a man starts complaining of symptoms.

If a man had a testosterone level of 900 for most of his life, and now is at 420, will he feel worse than previously? Almost undoubtedly, yes. Will he feel worse than a man who started at 700 and is now 420? We don’t know the answer. Is how he feels a ratio of his baseline testosterone to his current testosterone levels, or is it the absolute number? We don’t know!

Why do some men feel dramatically worse as their testosterone levels fall, and some men not notice the difference? We don’t know!

Why are some men exquisitely sensitive to their levels, and feel good only within a certain narrow range, while for others once they reach a certain level they notice no differences as the levels go up and down? We don’t know!

What we do know, is that most men with significantly lower than average levels, but still within the “normal” range (the middle 95% of men their age) will feel better with a higher testosterone level.

Will testosterone treatment affect fertility?

A special concern for younger men considering testosterone replacement therapy (TRT) is fertility since testosterone will shut down sperm production, either partially or completely.

Spermatogenesis (the production of sperm) in all men is dependent on production of testosterone by the testes. If testosterone is given from outside the testes (exogenous testosterone), as in TRT, the testes will then stop producing their own testosterone. This will actually shut down sperm production either significantly or completely in almost all men. This may be a temporary or permanent effect.

It is very important that younger men who still plan to have a family take this into account. Physicians specializing in TRT and fertility can manage men with low testosterone in other ways, specifically in ways that cause men to increase their own production of testosterone. This can be done at the pituitary level (clomiphene citrate or selective estrogen receptor modulators/SERMS) or at the testicular level (hCG.)

Limited studies have also shown that treating men with nasal testosterone (brand name Natesto, but also available from compounding pharmacies if not paid for by insurance) suppresses sperm production but does not turn it off. The effects on fertility are thought to be more easily reversed for men on nasal testosterone. The mechanism for this is that each application is short acting, and thus does not shut down the pituitary’s production of FSH and LH.

In our experience, men feel better on either SERMs or hCG than they did at their baseline. However, they usually do not feel as well as they would on actual testosterone. Also, once men have started testosterone, they do not feel great when they are coming off of it, even if supported by clomiphene citrate and hCG.

Fertility Preservation: Sperm Banking

If there is a small chance that a younger man, straight or gay, starting HRT will want to conceive in the future, we suggest that he bank his sperm, prior to beginning TRT.  Maze is the largest sperm bank in the tristate area for autologous use (for you and your partner). It is under the supervision of Dr. Michael Werner, who is also a fellowship trained male infertility expert, and will work with you and your partner’s doctors to use the sperm in the future. 

We can usually complete your sperm banking in 7-10 days, and then start treatment.

A low level of testosterone for a specific age does not in and of itself necessitate treatment. However, if your testosterone levels are low for your age and your symptoms are bothersome, we will treat you!

Learn more about Low T Symptoms and Treatment Options and Testosterone Replacement Therapy.

Last updated: December 2023