Testosterone levels in menopause – understanding your result

Thanks to the hard work and advocacy of a few campaigners, it is becoming increasingly recognised that adding testosterone to routine menopausal hormone replacement therapy with oestrogen and often a progestogen can bring marked additional benefits, particularly around sexual desire and enjoyment.

Based on the evidence available to date, testosterone is only prescribed for low levels of sexual motivation that are causing distress. This condition is known as hypoactive sexual desire disorder (HSDD). There’s an additional criterion – your testosterone levels must be in the lower half of the ‘normal’ range for your age. So how do you know if your level is in this range?

What happens to testosterone levels in menopause?

One reason testosterone levels don’t fall abruptly at menopause is that the ovaries aren’t the main producers of testosterone as they are with oestrogen and progesterone. About a quarter of your testosterone is made by the ovaries. Another quarter is made by the adrenal glands, fortune cookie-sized glands that sit atop the kidneys. The remaining 50% is made in various tissues around the body from related compounds made by the ovaries and adrenals.

Remove the ovaries, however, as happens with surgical treatment for some cancers or with a total hysterectomy, and testosterone levels do fall much more quickly, leading to more frequent and more severe symptoms.

What are normal testosterone levels in menopause?

Different laboratories have different ‘normal’ ranges depending on the methods and equipment they use. Here, we’re using ranges from scientific papers [1,3]. Your lab may have a different range, so you should refer to the range on your own lab results. Depending on where you are, the results may be reported in ng/dL (mostly in the US) or nmol/L (everywhere else). If you need to convert between the units, you can do it here.

Our range for a woman aged 45 to 54 is 27 – 38.6 ng/dL. Sometimes this is reported as 0.27 – 0.39 ng/ml.

This range is equivalent to 0.94 – 1.35 nmol/l

How do I know if my testosterone level is in the bottom half of the range?

So how do you work out if your testosterone level is in the bottom half of the range? If you’re eagle-eyed, you’ll have noticed that the graphs’ median line or halfway point is more than halfway down the range. This indicates that most women’s levels are clustered at the lower figures, whilst a few are spread across the higher part of the range. Laboratory results give the ‘normal’ range rather than the median value, so the best we can do is find the halfway point of the laboratory range. Ideally, the lab will give the normal range for different ages or at least pre- and postmenopausal.

You can find the middle of the range by adding the lower and upper limits and dividing by two.

For example, let’s say your lab gives you this result:

The normal or reference range is 27 to 38.6.

First, we add these together: 27 + 38.6 = 65.6

Now we divide 65.6 by 2: 65.6 ÷ 2 = 32.8

So, in this case, since the lab result is 31, that’s below the middle of the range (32.8) and so in the bottom half of the range.

Is a single testosterone blood test enough?

Testosterone levels vary throughout the day. You will usually be asked to have your blood taken in the morning, as that’s when levels are highest.

Testosterone levels also vary with the menstrual cycle, peaking mid-cycle.

Because blood testosterone levels are pretty variable, your doctor may want to get a couple of tests a few weeks apart to be sure that your testosterone result is a true reflection of what’s happening. This is to avoid side effects if you are given testosterone replacement therapy.

Let’s say your testosterone is generally in the upper part of the range, but a single blood test happened to catch it at a lower level. In that case, if you started taking testosterone replacement therapy, it could push your levels above the normal range. That’s when you may run into trouble with side effects such as oily skin, acne, facial hair growth and enlargement of the clitoris.

Testosterone results can be tricky to interpret

We’ve seen that a ‘normal’ testosterone level depends on your age. It’s also affected by the time of day and the time in your menstrual cycle. We’ve also seen that different labs have different normal ranges, and results can be reported in various units. It’s all getting a bit complicated. But wait… there’s more!

There are more reasons why interpreting your testosterone level may be less than straightforward:

• There haven’t been any extensive studies looking at women’s testosterone levels. So our normal ranges are based on small studies and may not be representative.

• Testosterone analyses were designed for men, whose blood levels are ten times higher than women’s. That means the tests are less accurate at measuring the lower levels in a woman’s blood.

• There is debate about how helpful a testosterone blood result is. This is because blood testosterone levels may not correlate well with testosterone levels in tissues or inside cells. Some testosterone may be produced in cells from other hormones circulating in the blood [2].

• Importantly, most testosterone in the blood is stuck to proteins, most notably sex hormone binding globulin (SHBG). Testosterone not attached to SHBG is called free testosterone. If you add together testosterone bound to SHBG and free testosterone, you get total testosterone – this is the level usually measured. Generally, testosterone attached to SHBG isn’t active. So, you can have normal total testosterone but a low free, active testosterone level.

Blood tests to measure free testosterone are complicated, expensive and not terribly accurate, though there are calculations you can use to estimate how much testosterone is free if you know the levels of total testosterone and SHBG.

Levels of SHBG can be helpful to understand why testosterone replacement therapy isn’t working, or why you’re getting side effects

Since testosterone stuck to SHBG is inactive, higher levels of SHBG mean more testosterone is taken out of action, while lower levels of SHBG mean more free, active testosterone. As you can see from the table, various diseases and factors can change your SHBG and thus also raise or lower your free testosterone level [4].

Interestingly, we know that testosterone levels fall gradually with age, but levels of SHBG rise at the same time. That means even more testosterone is bound to SHBG and thus inactive.

As if this wasn’t complicated enough, recent evidence suggests that not all free testosterone is active and not all testosterone bound to SHGB is inactive.

Experts recommend that the total testosterone level is most helpful to determine if testosterone should be prescribed and ensure that levels don’t go too high [2]. SHBG levels can be helpful to understand why testosterone treatment isn’t working (SHBG may be high and stopping the testosterone from working) or why you might be getting side effects despite normal blood testosterone levels (SHBG might be low, so a higher than expected fraction of the testosterone is free and active).

As acceptance of testosterone HRT grows and more women use it, our experience and understanding will increase, more research will be done, and questions will be answered. For the moment, when even many doctors are not well informed on the topic, educating yourself through reliable sources is the best way to ensure you can advocate for yourself and get the best treatment.

Sources

1. Davison, S.L., Bell, R., Donath, S., Montalto, J.G., Davis, S.R. (2005). Androgen Levels in Adult Females: Changes with Age, Menopause, and Oophorectomy. The Journal of Clinical Endocrinology & Metabolism, 7, 3847-3853.
2. Parish, S.J., Simon, J.A., Davis, S.R. et al. (2021). International Society for the Study of Women’s Sexual Health Clinical Practice Guideline for the Use of Systemic Testosterone for Hypoactive Sexual Desire Disorder in Women. The Journal of Sexual Medicine, 18, 849-867.
3. Uloko, M., Rahman, F., Ibrahim Puri, L., Rubin, R.S. (2022). The clinical management of testosterone replacement therapy in postmenopausal women with hypoactive sexual desire disorder: a review. International Journal of Impotence Research, 34, 635-641.
4. Smith, T., Batur, P. (2021). Prescribing testosterone and DHEA: The role of androgens in women. Cleveland Clinic Journal of Medicine, 88(1), 35-43