Do Testosterone Levels Change Throughout The Day?

Take-home points

• Testosterone levels usually peak in the morning and fall to their lowest in the early evening.
• When testosterone is highest and lowest is mainly due to sleeping patterns, so timings may differ for people who sleep and wake at different times (e.g. nightshift workers).
• Young and healthy men have more prominent changes in their daily testosterone levels than older men and men with hypogonadism.

What is testosterone?

Testosterone is the main hormone that produces masculine characteristics, influencing everything from physical appearance to behaviour. In some ways, it is the essence of what makes a man a man. Deepening of the voice, muscle development, strong bones, sexual desire and function—these are all outcomes that relate to increased testosterone levels throughout childhood and normal testosterone levels throughout adulthood. Women share these traits too, of course, but they produce far less testosterone than men do.

What is the normal range of testosterone levels?

‍The British Society for Sexual Medicine defines a normal serum testosterone (total testosterone) level as between 10.4–34.7 nanomoles per litre (nmol/L) for adult men.¹ This figure equates to 300–1,000 nanograms per decilitre (ng/dL). However, what is considered clinically low levels of testosterone varies across guidelines, typically from 230–340 ng/dL.

What are normal testosterone levels in women?  

The normal serum testosterone level in women is less clear but seems to be about 20 times lower than men, 0.5–2.4 nmol/L (15–70 ng/dL).

For more information on the types of testosterone and how to interpret testosterone test results, read our dedicated article on this topic.

When is testosterone highest and lowest throughout the day?

Testosterone levels fluctuate throughout the day, an effect known as diurnal variation. For most people that wake up in the morning and sleep in the late evening, the time of the day when testosterone levels are highest is between 5.30–8.00 am before reaching their lowest levels in the early evening, roughly 12 hours later.² The effect is primarily driven by sleeping patterns, so the timings will differ—perhaps be the exact opposite—for nightshift workers.³

Graph: Testosterone levels throughout the day in males

When testosterone levels are at their highest and lowest, they are usually 10–25% off the average level across a 24-hour period.^2,4,5,6 However, some reports have found testosterone levels can be 2–3 times higher in the morning compared to the evening.^7,8

Does age affect how testosterone levels fluctuate throughout the day?

Fluctuations in testosterone levels throughout the day are not the same in older versus younger men. One study found that although the testosterone levels of older men are not 100% stable, there is no clear peak or trough in the testosterone levels as there is for younger men.⁶ Another study found something quite different, that older men still have daily fluctuations in testosterone but the amount of variation was blunted compared with younger men.⁹ The reason for the contrasting results has not been established, but there are clearly differences of some kind in testosterones diurnal variation between older and younger men.  

It has been speculated that older men have less diurnal variation in testosterone as their testosterone levels are generally lower, supported by the same effect occurring in men with hypogonadism (low testosterone).¹⁰ But women, who have considerably less testosterone than men, still experience large diurnal variation in testosterone, alike to younger men¹¹. This would suggest that differences in diurnal variation between older and younger men have something to do with the aging process. Future research is needed for clarity on this topic.

Read more about the relationship between age and testosterone here

Do fluctuations in testosterone levels affect testosterone tests?

If you have been scheduled for a standard testosterone test, you should have been advised to take it in the morning when testosterone levels are at their peak. Although rare, some people are incorrectly diagnosed with low testosterone because their test is performed later in the day.  

If you are interested in how your testosterone levels change throughout the day, it would require you to take at least two testosterone tests—one early in the day and another later in the day.

As always, we recommend speaking with a healthcare professional if you want to clarify how the information in this article affects you personally. It may or may not be relevant, depending on your situation.

References‍

1. BSSM. Available at: https://bssm.org.uk/wp-content/uploads/2023/02/BSSM-Practical-Guide-High-Res-single-pp-view-final.pdf (Accessed March 2024).
2. Brambilla DJ et al. J Clin Endocrinol Metab 2009;94(3):907–913.
3. Kelly MR et al. J Endocr 2022;6(12):bvac153.
4. Tenover JS et al. J Gerontol 1988;43(6):M163–169.
5. Plymate SR et al. J Androl 1989;10(5):366–371.
6. Brember WJ et al. J Clin Endocrinol Metab 1983;56(6):1278–1281.
7. Diver MJ et al. Clin Endocrinol (Oxf) 2003;58(6):710–717.
8. Winters SJ et al. J Androl 1991;12(3):185–190.
9. Novaes LF et al. J Sex Med 2024 (online ahead of print).
10. Gupta SK et al. J Clin Pharmacol 2000;40(7):731–738.
11. Algburi Sr HD et al. Cureus 15(10):e47677340.