What are Normal Male Testosterone Levels?
Testosterone deficiency is a growing epidemic. Men’s testosterone levels have dropped 20% in the last 20 years and more and more younger men are suffering the effects of low testosterone. Just look around today and you can see depressed, weak-looking men everywhere.
Many do not know any different and have lead lives of depression and anxiety, struggling from day to day… I would know, this used to be me.
So what’s happened? Should we be happy with what we are told are ‘normal male testosterone levels’?
Testosterone levels in men
As you can see in the graph above, the average testosterone level in the population is dropping every decade. You would expect that as a result, more and more men would be suffering from low testosterone.
In fact, the rates of men being treated for this condition has increased but not in line with the drop we see in overall levels.
Whilst there are many reasons for this reduction in male hormone levels, from obesity to environmental chemical exposure, it remains difficult for the medical community to become comfortable with diagnosing and treating this issue.
There are complex reasons behind this. These range from poor knowledge and understanding of the condition, to stigma around testosterone itself, to the use of inaccurate normal male testosterone levels in laboratory results.
Here we will look at the history behind these values and how they are measured. We will look at why they are not a good indicator of low testosterone when used alone or relied on entirely without taking symptoms into account.
We will consider the importance of looking at more than just one value and how different factors can affect the amount of testosterone available for use by the body.
What is testosterone?
Testosterone is a hormone or chemical messenger produced mainly by the testes in men and in smaller amounts in women. It is considered a sex hormone due to its effects on the sex organs and production of male characteristics and behaviours.
It has effects throughout the body, affecting the body, the mind, behaviour, fertility and development.
It is extremely important for male well-being and physical health, which makes it even more surprising that some parts of the medical community are so against treating it effectively.
How is testosterone measured?
Testosterone is usually measured through a capillary blood test at home (you can find these here) or taken by a doctor, phlebotomist or nurse from a vein.
The test is taken at around 9am due to the release time of testosterone in the body (known as the circadian rhythm). This is the time when testosterone blood levels are at their highest.
This serum blood test is then analysed in a laboratory and different hormones reported on. These come back on a form with the ‘normal’ male testosterone levels attached (see below).
These are my test results from before starting TRT. As you can see I had ‘normal’ total and low free testosterone levels. This is despite having several symptoms of low testosterone.
If I’d visited a UK NHS GP I would have undoubtedly been told that I was just depressed and anxious.
I had insomnia, couldn’t think straight, had trouble with simple arithmetic, was losing the muscle and strength I had trained the past 10 years for, I was grumpy and lethargic and I had anxiety the whole time – my life was a mess.
You may be asking, ‘what do these values all mean?’. The important ones to understand now are the ‘total testosterone’ and ‘free testosterone’ levels.
Total testosterone can be an indicator of low levels of testosterone. However, the Endocrine Society (amongst others) have rightly indicated that many men have ‘normal’ total testosterone levels but very low ‘free’ and/or ‘bioavailable’ testosterone levels. If this is the case then a man may have all of the symptoms of low testosterone but show as normal on a total testosterone test.
Guess which values are tested for by most doctors?
You’re right: they only usually test for total testosterone.
And if this is ‘within normal male testosterone levels’ the patient will be told that it is all fine and that something else is to blame for their symptoms (usually depression or anxiety).
What are normal male testosterone levels?
‘Normal values’, as listed on laboratory reports, are the range of levels of testosterone found in studies of male populations.
In the case of most values produced these are from an age range of 20-80 year old men! They also include men with illnesses and in varying degrees of stress/environmental factors.
The researchers then take all of the results from this group of men from different age groups and states of health and put it in a graph.
Then, a % of the top and bottom values are removed (by using statistical analysis such as standard deviations from the mean) and you are left with the ‘normal’ male testosterone levels/values.
Can you see the problem with this?
If we know that the average man’s free testosterone levels drop over time from the age of 30, then it is clear that comparing a 20 year olds’ levels with the testosterone levels of an 80 year old is rather silly!
Unfortunately, this is what happens in GP surgeries across the country. Men are being denied treatment from GP surgeries despite suffering from very real and debilitating symptoms.
One of my friends was told that he couldn’t possibly have low testosterone because he could grow a beard (he was found to have low testosterone and is now on TRT).
Another was told that he was ‘too muscley’ to have low testosterone. Examples of these kinds of statements are popping up frequently, and show a real distrust for the idea of TRT in itself my many GPs. Many men who have low testosterone are being treated with anti-depression medication (SSRIs) instead of treating the real conditions behind their mental health issues. These medications often reduce testosterone production even further, exacerbating the condition (studies in animals only so far).
Another issue with these ‘normal’ testosterone levels is that the laboratories responsible for producing the values have different ideas of what constitutes a low level that needs treatment. They vary considerably and can result in a man not receiving the treatment they require and would benefit from if they were tested elsewhere.
How do these normal testosterone levels compare?
There are differences in laboratory ranges and recommended ranges across the world. These depend on the population of the country, the studies used to produce the ranges and the reasoning behind the ranges used.
In the UK, the ranges differ between 8.6 – 29nmol/l (a standard range used by the NHS and most laboratories) to 10nmol/l – 41nmol/l. The BSSM (British Society of Sexual Medicine) recommends that testosterone replacement therapy should be offered to patients with levels below 12nmol/l or total testosterone or a free testosterone of 0.225nmol/l and below.
They also suggest that men with a raised LH (luteinising hormone, a hormone which stimulates the testicles to produce testosterone) should be considered for TRT. In the US, some clinics will provide testosterone to men with higher levels.
Many clinicians believe that a trial of treatment should be provided to see whether this will improve symptoms. Whilst this may be appropriate for some patients, the risk of side effects needs to be weighed up, especially if higher doses are used (as in many US clinics). There is some evidence that certain symptoms of low testosterone e.g. low mood, is present up to 15nmol/l and improved by TRT.
Why are these values not a good indicator of low testosterone?
Doctors are assessing 20-year-olds’ testosterone levels based on the average levels of all men including 80-year-old men with comorbidities (other illnesses). The decision that someone has low testosterone is based on them being in the lowest 5% of these men. It is not at all related to the symptoms of those men.
The ‘normal’ levels only look at the highest to lowest levels of all men in a population, they haven’t correlated this with whether the men in that population are experiencing low testosterone symptoms! If doctors look purely at these reference ranges then they ignore the fact that some men will experience low testosterone symptoms at higher levels of testosterone than other men.
The graph below demonstrates how the reference ranges are calculated using standard deviations. Note that it has completely different ‘average’ testosterone levels to what we see in other studies. The red and blue areas combine to produce the range of ‘normal’ testosterone levels.
‘Total testosterone levels are affected by alterations in SHBG that occur in obesity, old age, diabetes mellitus, hyper- and hypothyroidism, and acromegaly, and in men taking certain medications. Accurate and reliable assays for free or bioavailable testosterone measurements usually are not available in local laboratories, and these tests should be performed in a reliable reference laboratory. Free testosterone measurements by analog methods are frequently available in local laboratories, but these measurements are affected by alterations in SHBG and are inaccurate. Their use is not recommended.’
As you can see even The Endocrine Society discourages doctors from relying on just total testosterone levels, yet because the test for free testosterone isn’t as cheap or easy to attain it is often neglected by GPs. Read more from the Endocrine Society guidelines here.
Free and bioavailable testosterone
Only 0.5–3% of circulating testosterone is unbound or “free. ” The term “bioavailable testosterone” refers to unbound testosterone plus testosterone bound loosely to another hormone: albumin. This term is because it is thought that in addition to the unbound testosterone, albumin-bound testosterone is bioavailable because it can separate from albumin to be used in the body.
‘Free or bioavailable testosterone concentrations should be measured when total testosterone concentrations are close to the lower limit of the normal range and when altered SHBG levels are suspected, e.g. in older men and in men with obesity, diabetes mellitus, chronic illness, or thyroid disease’.
So it is easy to see why just measuring total testosterone is not sufficient to diagnose testosterone deficiency!
What are normal male testosterone levels by age?
|Age Range||Average total testosterone (nmol/l)||Average free testosterone (nmol/l)||SHBG|
Unfortunately, we don’t have good results which show testosterone levels for normal people without symptoms etc. We have to rely on a combination of averages and the studies we do have looking at when patients get symptoms.
It is worth remembering that all of this is individual. If you have a ‘low’ testosterone level but no symptoms then that does not mean TRT is the right choice for you. These results have been available since 1996 yet they continue to be ignored in favour of more generalised values.
The best option would be to produce lab ranges which are based on some more comprehensive studies of the average levels of men combined with the levels at which the average man gets symptoms.
These results do show a reduction in testosterone levels with age, as well as an increase in SHBG and a further reduction in average free testosterone levels with age. It also demonstrates why SHBG and free testosterone are so important for testing. You can see the updated 2005 study by Vermuelen and Kaufman here.
You can see that SHBG (sex hormone binding globulin), which attaches to testosterone and makes it unable to bind to receptors in the body, rises with age.
This is one reason why a man’s free testosterone drops so much with age. And it’s another good reason to always have free testosterone checked when worried about low testosterone symptoms!
There are several studies which show that a man’s testosterone levels decrease gradually with age – around 1.6% on average per year for total testosterone and 2-3% per year for free testosterone (Mohr et al 2005, Zirkin and Tenover 2012, amongst others).
DHEA is another testosterone precursor (testosterone is produced from it) which drops massively with age. It is responsible for many male traits and physical changes in the body. It has been shown to increase strength and reduce body fat levels in men. Many men take it as an anti-ageing supplement.
With lower testosterone levels this precious hormone also reduces significantly.
Treat the patient not the lab results!
So what is the take-home message for all of this?
Treat the patient, NOT the blood results.
A man who had very high testosterone levels when a younger man may have very real and devastating symptoms but be within the lower ranges of the ‘normal values’. He will be chased out of the average GP’s office when his blood results come back within range.
Similarly, a young man of 25 years old may feel extremely fatigued and depressed at a testosterone level similar to that of a low-testosterone 80 year old. But based on the ‘normal male testosterone values’ be considered normal! He will be struggling with all of the symptoms of low testosterone and will probably be put on SSRIs to attempt to treat his depression and anxiety.
This is why we at OptiMale believe in assessing both normal blood values and a patient’s symptoms. If you come to us with low-normal testosterone levels our doctors can often offer a trial of testosterone replacement therapy to assess whether this is the cause of your symptoms.
If you are noticing several of these symptoms then it is definitely worth getting your testosterone blood results tested.
It is a simple, quick test that you can do at home. You will receive it directly through the post and we test for everything including total testosterone, free testosterone, SHBG and oestrogen levels at an extremely competitive price.
- Riggin L, Koren G. Effects of selective serotonin reuptake inhibitors on sperm and male fertility [Effets des inhibiteurs sélectifs de la recapture de la sérotonine sur le sperme et sur la fertilité masculine]. Can Fam Physician. 2015;61(6):529-530.
- Cheung KK, Luk AO, So WY, et al. Testosterone level in men with type 2 diabetes mellitus and related metabolic effects: A review of current evidence. J Diabetes Investig. 2015;6(2):112-123. doi:10.1111/jdi.12288
- Kaufman JM, Vermeulen A. The decline of androgen levels in elderly men and its clinical and therapeutic implications. Endocr Rev. 2005;26(6):833-876. doi:10.1210/er.2004-0013
- Samaras N, Samaras D, Frangos E, Forster A, Philippe J. A review of age-related dehydroepiandrosterone decline and its association with well-known geriatric syndromes: is treatment beneficial?. Rejuvenation Res. 2013;16(4):285-294. doi:10.1089/rej.2013.1425
- Mohr BA, Guay AT, O’Donnell AB, McKinlay JB. Normal, bound and nonbound testosterone levels in normally ageing men: results from the Massachusetts Male Ageing study. Clin Endocrinol. 2005;62:64–73.
- Zirkin BR, Tenover JL. Aging and declining testosterone: past, present, and hopes for the future. J Androl. 2012;33(6):1111-1118. doi:10.2164/jandrol.112.017160