Reference Published April 17, 2026

Testosterone Levels by Age: What's Normal, What's Optimal

What counts as a "normal" testosterone level? Depends on your age, the lab's reference range, and whether you mean normal or optimal. Here's what the data shows by decade, and why the numbers most doctors use might be set too low.

The Standard Reference Range

Most US labs use a reference range for total testosterone of roughly 264 to 916 ng/dL (9.2 to 31.8 nmol/L) for adult men. If you fall inside that range, you're labeled "normal" and probably won't be flagged for further workup.

The annoying thing is this range has real problems. It's built from population averages that lump in men of all ages and health statuses. A 25-year-old and an 85-year-old share the same range, even though their physiology couldn't be more different. Population "normal" also includes a lot of men who are overweight, sleep-deprived, or otherwise not optimal. Normal is not the same thing as healthy or optimal.

Typical Levels by Age

These are median values from large population studies. Your actual level can vary considerably from the median for your age group.

Teens and Early 20s

Peak natural testosterone. Median total T around 600 to 700 ng/dL. Free T proportionally high because SHBG is typically lower in young men. This is the reference against which everything else declines.

Late 20s to Mid 30s

Still near peak. Median around 550 to 650 ng/dL. Many men in this range feel great but start to notice that recovery from poor sleep or heavy training is slower than it was at 22.

Late 30s to 40s

The gradual decline kicks in. Most men lose about 1 to 2% of testosterone per year starting around 30. Median by mid-40s is around 450 to 550 ng/dL. This is where a lot of men start noticing symptoms, especially if they're trending toward the lower end.

50s

Median around 400 to 500 ng/dL. SHBG starts rising with age, which means free T drops faster than total T. Plenty of men in their 50s have a total T that looks "normal" but free T that's clearly low.

60s and Beyond

Median around 350 to 450 ng/dL. The combination of lower production and higher SHBG means clinically meaningful symptoms are common. Obesity, type 2 diabetes, and sleep apnea are more prevalent in this group and accelerate the decline.

Normal vs Optimal

Here's the tension. If the reference range for "normal" is 264 to 916, a healthy 30-year-old sitting at 300 is technically in range. But 300 is also where symptoms of hypogonadism start showing up in most men. Normal is a statistical term, not a health term.

What many functional and sports medicine doctors consider "optimal" for adult men who want to feel good, train hard, and have a healthy libido:

Total T: 500 to 900 ng/dL.
Free T: Above the upper third of the lab's reference range.
SHBG: 20 to 50 nmol/L (not too high, not too low).
Estradiol: 20 to 40 pg/mL (not suppressed, not elevated).

Whether you can get to optimal via lifestyle depends on your starting point. See how to increase testosterone naturally for the full playbook.

The Generational Decline

One of the more striking findings in recent endocrinology: average testosterone in American men has been declining across generations, independent of age. A 2007 study in The Journal of Clinical Endocrinology & Metabolism (Travison et al.) found that a 60-year-old man in 2004 had roughly 17% lower T than a 60-year-old in 1987.

The reasons aren't fully clear. Proposed contributors: rising obesity rates, less physical activity, worse sleep, endocrine-disrupting chemicals (phthalates, BPA), chronic stress. The upshot is that being in "normal" range for today's average doesn't necessarily mean robust health. The average itself has shifted lower.

How to Interpret Your Own Numbers

A few practical rules:

One test isn't enough. Testosterone varies day to day by 20 to 30%. Confirm important findings with a repeat test.
Morning draw matters. T is highest between 7 and 10am. Afternoon draws will be lower.
Total T alone is incomplete. Always look at free T and SHBG together.
Context is everything. A 550 total T with no symptoms is fine. A 550 total T with fatigue, low libido, and a high SHBG is worth investigating.
Age isn't destiny. A 55-year-old with good lifestyle habits can have higher T than a 30-year-old with poor habits. The decline curve is not fixed.

Free T and SHBG, Explained

Only about 1 to 3% of your testosterone is free. The rest is bound to proteins, mostly SHBG and albumin. "Free T" is the biologically active portion your tissues can actually use.

SHBG rises with age, with caloric restriction, and with thyroid hormone. It falls with insulin resistance and obesity. Two men with identical total T can have wildly different free T depending on SHBG.

If your total T is mid-range but you feel terrible, check SHBG. High SHBG paired with normal total T is one of the more under-diagnosed situations in aging men.

Quick Takeaways

"Normal" range (264-916 ng/dL) includes a lot of symptomatic men. Normal is not the same as optimal.
Testosterone declines 1-2% per year after 30. The trajectory depends heavily on lifestyle.
Average T has been declining generationally. "Normal today" may be lower than "normal 30 years ago."
Always check total T, free T, and SHBG together. Context matters more than one number.
Morning draw, fasted, repeated for accuracy.

Not medical advice. Reference ranges vary by lab. Interpretation should always happen in consultation with a qualified physician.