Hormones are a complicated thing—for both men and women.

During our teenage years and throughout adulthood, they can fluctuate quite a bit, which means things like mood swings, a raging sex drive, or whatever else have you. And then once you hit a certain age, it takes a turn for the worse, and levels inevitably start to drop.

It’s something we all dread. For women, that’s menopause; for men, it’s around the age of 40 when testosterone levels start to plummet if you’re not making a conscious effort to keep them boosted.

If you’re a little concerned, or maybe confused, about your testosterone levels and aren’t sure if you fall into the norm, this article is going to give you an overview of why proper testosterone levels are important and the benchmark you should be going for at your age.

Why Testosterone Is Important

Just like progesterone and estrogen control a slew of functions for females, testosterone does the same for men.

Most people associate testosterone solely with pubescent factors like hair growth, deepening of the voice, and sex drive, but it’s also part of several other functions.

About 95% of a man’s testosterone is produced in the testes under control of luteinizing hormone (LH), with the remaining 5% produced from the adrenal glands.

It’s produced by the Leydig cells in the testes from its precursor cholesterol, so if you don’t have adequate cholesterol, your levels may suffer. But cholesterol is also the building block of all sex hormones, both male and female.

Between cholesterol and testosterone, we also have androstenedione, another hormone that is sometimes supplemented by fitness people and athletes worldwide to boost T levels and is touted as a “natural” alternative to anabolic steroids. Whether you should be taking this, however, is debatable.

We’re all familiar with the effects of testosterone during puberty, but there are more:

  • Muscle mass
  • Bone strength
  • Red blood cell production
  • Behavior
  • Sexual performance
  • Sperm production
  • Cholesterol metabolism

The list goes on, which means that having adequate amounts of testosterone throughout your life is critical for your health and well-being, regardless of your age.

Average Levels

When it comes to what the average testosterone levels are, the reality is they’re constantly fluctuating over a lifespan—not as bad as women’s hormones, but they still range.

At puberty, surges in GnRH and LH fire up testosterone production, which is put towards stimulating bone and muscle development, red blood cell production, voice development, facial and body hair growth, genital enlargement, along with sexual function and reproductive capacity.

Testosterone levels typically peak around 17 and will remain high throughout the 20s and 30s, even into the 40s. In general, most healthy men will produce about six milligrams of testosterone per day.

Testosterone levels remain high throughout life for some men, but most often, they start to decline around 40.

Unlike female hormones, several studies suggest test levels decline at a pretty steady pace as men age, but there is no period of accelerated decline 1.

This decline happens at a rate of about 1% per year, which equates to an average of 0.110 nmol/L (3.2 ng/dL) yearly drop 2, 3.

But the question of what’s the average testosterone level isn’t as simple as giving a concrete value.

Men exhibit a wide range, with levels anywhere from 270 to 1,070 ng/dL. And like other hormone values, testosterone levels follow a rather cyclical pattern that fluctuates over 24 hours; it runs along the same patterns as our circadian clock.

Levels are highest around 8 am and steadily decrease to hit their lowest around 9 pm. The time you test levels at will determine the value you get.

Aging also puts a new factor into the equation. Testosterone travels in the blood in one of two forms: bound or free.

When it’s bound, it binds tightly to sex hormone–binding globulin (SHBG) and weakly to albumin. Only the free and albumin-bound forms of testosterone are biologically active (what we measure).

However, SHBG levels increase with age, so older men may have normal total testosterone levels, but still be low in bioavailable testosterone.

One study found that total testosterone peaks at about 15.4 nmol/L (444 ng/dL) at age 19 and falls in the average case to 13.0 nmol/L (375 ng/dL) by age 40 years, with no subsequent falls with increasing age 4.

And according to guidelines from the American Urological Association (AUA), testosterone levels of at least 300 nanograms per deciliter (ng/dL) are normal for a man 5. Anything below that is usually considered low.

Low Testosterone

We know it’s not the greatest thing to hear, but because testosterone levels naturally decline with age, it can lead to things like:

  • Hair loss (face and body)
  • Difficulty gaining or maintaining muscle mass
  • Low libido
  • Mood swings
  • Memory or concentration issues

And while age is a big determinant of your testosterone levels, certain factors also play into whether you fall into the normal range or not. That’s things like smoking, physical activity, diet, stress, and more.

But the problem with inadequate testosterone levels is that aging men also encounter various health challenges that testosterone plays into, such as bone mineral density, lean body, and muscle mass, strength, and aerobic capacity, plus increases in total and abdominal body fat, LDL cholesterol, and/or LDL/HDL cholesterol ratios 1.

So, when you don’t have enough testosterone to support these functions, health complications arise.

Final Thoughts

Hormone levels are far from a simple thing. Like we said, male hormones are much more steady than female hormones that fluctuate throughout the month, so once you hit your late teens, testosterone levels should be pretty consistent until your 40s.

If you’re experiencing symptoms of low testosterone, adding in a natural test-booster like Testo Lab Pro could be to your benefit.


  1. SM Harman, EJ Metter, JD Tobin, J Pearson, MR Blackman. Longitudinal effects of aging on serum total and free testosterone levels in healthy men. Baltimore Longitudinal Study of Aging.J Clin Endocrinol Metab. 2001;86(2):724-731.
  2. JM Zmuda, JA Cauley, A Kriska, NW Glynn, JP Gutai, LH Kuller. Longitudinal relation between endogenous testosterone and cardiovascular disease risk factors in middle-aged men. A 13-year follow-up of former Multiple Risk Factor Intervention Trial participants.Am J Epidemiol. 1997;146(8):609-617.
  3. HA Feldman, C Longcope, CA Derby, et al. Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study. J Clin Endocrinol Metab. 2002;87(2):589-598.
  4. TW Kelsey, LQ Li, RT Mitchell, A Whelan, RA Anderson, WH Wallace. A validated age-related normative model for male total testosterone shows increasing variance but no decline after age 40 years [published correction appears in PLoS One. 2015;10(2):e0117674]. PLoS One. 2014;9(10):e109346.
  5. JP Mulhall, LW Trost, RE Brannigan, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline.J Urol. 2018;200(2):423-432.