Home › Biomarkers › Testosterone, total
In a study of 944 Chinese men aged 40 to 79, 9.1% had three sexual symptoms at once, together with a total testosterone below 13.21 nmol/l and a low free testosterone.[1]
On this page you can read what testosterone, total is, what the guidelines say about a value that is too low or too high, what affects your value and which other values are best to look at alongside it.
Also known as: serum testosterone, total testosterone. At the lab: TES.
Testosterone is a hormone. Hormones are chemical messengers in your blood. They control what certain cells or organs do. Testosterone is often seen as a male hormone, but women have it too, in smaller amounts.[2]
Most of the testosterone in your blood is bound to proteins, such as SHBG and albumin. A small part is free. Your body can use free testosterone more easily. Because most of it is bound, your body does not use too much of it.[2]
There are three tests for testosterone. The total testosterone test measures the bound and the free part together. This is the most widely used test.[2]
In everyone, testosterone helps with sex drive and with the growth of muscle and bone. In men, it also plays a part in body hair, making sperm and making new red blood cells.[2]
A testosterone test on its own does not give a diagnosis. An abnormal level together with symptoms can point to a health problem, though. That is why your doctor often uses the test together with other tests.[2]
In a study of Chinese men aged 40 to 79, three sexual symptoms were linked to total and free testosterone: being able to have sex less often or less well, fewer morning erections and a lower sex drive.[1]
The lab BioProfile works with (Labplusarts) uses a reference range of 8.6 to 29 nmol/l for total testosterone. The lab calls a level between those limits normal.[3]
| Total testosterone | What it can mean | Who it is for |
|---|---|---|
| Below about 12.55 nmol/l[1] | Threshold for being able to have sex less often or less well, and for fewer morning erections | Chinese men aged 40 to 79 |
| Below about 14.35 nmol/l[1] | Threshold for a lower sex drive | Chinese men aged 40 to 79 |
| Below 13.21 nmol/l[1] | Linked to more of these three sexual symptoms | Chinese men aged 40 to 79 |
Thresholds from a study by Liu and colleagues of 944 Chinese men aged 40 to 79. They apply to this group, not to everyone.[1]
In men, a low value can be consistent with less interest in sex, trouble getting an erection, trouble getting someone pregnant, less muscle mass, or thinning bones or anaemia with no known cause. A low value can point to a problem with the testicles, a long-term condition of the liver or kidneys, a condition of the pituitary gland, problems with alcohol or certain hereditary conditions. In women, a low value is normal. An extremely low value can point to a condition of the adrenal glands, the pituitary gland or the ovaries.[2]
In women, a high level can go with extra hair on the body or face, hair loss at the temples and on top of the head, a changing voice, irregular or missed periods, trouble getting pregnant and spots. In women, a high level can point to a condition of the ovaries, the adrenal glands or the pituitary gland. In men, a high level can point to a condition of the testicles, steroid use or a condition of the adrenal glands. An abnormal result does not always mean there is something that needs care.[2]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
Your testosterone is usually highest in the morning. That is why blood is usually taken in the morning, between 7 and 10 am.[2]
It is normal for testosterone to fall with age. What your result means also depends on your age, your symptoms and your other results.[2]
Some medicines and hormone therapy can affect your testosterone. Sometimes you need to fast for a few hours or stop taking a medicine for a while. Never stop a medicine on your own: ask your doctor how to prepare.[2]
Testosterone, total is included in BioProfile 121 and 150.[4]
The BioProfile editorial team wrote this page on 10 October 2026 from the sources below, which we read on 10 October 2026. Every number on this page appears in one of those sources, with that source's number next to it. An expert has yet to check this page; after that check, the expert's name and the date of the check will appear at the top. This page offers explanation, not a diagnosis. Discuss a value outside the range with your GP.
