Lab Notes · 6 min read
If your testosterone came back low, or you think it might be, there is a plainer question sitting underneath that number. You want to know whether you can still build muscle. That one has been studied directly, and the answer is better than the number suggests.
Testosterone comes down slowly across a man’s adult life. The Baltimore Longitudinal Study of Aging measured the same men over and over for years, which is why the rate is known rather than guessed. It falls a little every year, and the share of men reading under the clinical cutoff climbs with each decade.
Harman et al., Journal of Clinical Endocrinology & Metabolism 2001;86(2):724–731 · 890 men followed longitudinally; roughly 20% of men over 60 and 30% over 70 below the hypogonadal threshold for total testosterone
Your muscle is doing something across those same years, and that is the part you can put your hands on.
Take the honest version of this first, because most of what you will read online skips it. Researchers pooled the exercise training trials run in men aged sixty and over and looked at resting testosterone before and after. Resistance training left it about where it started.
Hayes & Elliott, Frontiers in Physiology 2019;9:1878 · systematic review and meta-analysis, 22 studies in men aged 60 and over; resistance training effect on basal testosterone SDM −0.003, p = 0.986; endurance and interval training produced small increases
The same goes for the hormone surge right after a hard set. Men trained for twelve weeks while their post-exercise hormone responses were measured, and those responses were then compared against how much muscle and strength each man actually built. The hormones tracked with nothing.
Morton et al., Journal of Applied Physiology 2016;121(1):129–138 · 49 resistance-trained men, 12 weeks; acute post-exercise systemic hormone changes unrelated to hypertrophy or strength gains
So the muscle keeps its own score. That is the thing in you that answers to what you do in a gym.
A fiber grows in response to two local events. It has to be recruited, and once it is working it has to be loaded hard. Both of those happen inside the tissue under the weight, and they proceed on mechanics.
Pooled across forty-nine studies in adults past fifty, resistance training added lean body mass, and the programs with more work in them added more of it.
Peterson, Sen & Gordon, Medicine & Science in Sports & Exercise 2011;43(2):249–258 · 49 studies, 1,328 adults aged 50 and over; pooled mean lean body mass +1.1 kg, higher-volume programs significantly greater
In middle-aged and older men specifically, a recent review of the interventional work found the same direction inside a few months of lifting, with strength and aerobic fitness moving alongside it.
Green, Chasland, Yeap & Naylor, Sports Medicine – Open 2024;10:30 · review of interventional studies in middle-aged and older men; 12–16 week resistance training programs average about 1.3 kg of lean body mass
There is a group of men whose testosterone is driven down to almost nothing on purpose, as part of treatment for prostate cancer. They are the cleanest test there is of whether muscle needs the hormone in order to answer a barbell. Across twelve controlled trials in those men, exercise built lean mass and took fat off, and the programs built around resistance exercise did it best.
Shao et al., PLOS ONE 2022;17(2):e0263918 · 12 randomized controlled trials, 715 men on androgen deprivation therapy; lean body mass mean difference +0.88 kg, body fat mass −0.60
A response that survives that will survive a low reading on a routine panel. Whatever your testosterone is doing, the tissue is still listening to load.
Hormone questions belong with your own doctor. We are certified exercise specialists, we do not diagnose and we do not treat, and anyone under a physician’s care should be cleared by that physician before starting here.
Most men walk in wanting the fat gone, and that sits inside this same conversation. In men carrying obesity, losing a meaningful amount of body weight has been associated with higher testosterone readings, and how much weight came off was the best predictor of how large the change was. That is an association measured across groups of men, not a result anyone can promise you.
Corona et al., European Journal of Endocrinology 2013;168(6):829–843 · meta-analysis of 24 studies in obese men; total testosterone rose 2.87 nmol/L after low-calorie diet and 8.73 nmol/L after bariatric surgery, degree of weight loss the best determinant
Then comes the question the scale never asks. Losing weight takes muscle off along with the fat, and what decides the split is what you were doing while you lost it. Older adults on the same diet for six months lost the same amount of weight whether they did aerobic work or lifted. The lifters kept far more of their lean mass.
Villareal et al., New England Journal of Medicine 2017;376(20):1943–1955 · 141 adults, mean age 70, 26 weeks, about 9% of body weight lost in every group; lean mass −2.7 kg with aerobic exercise vs −1.0 kg with resistance exercise
Same thirty pounds, two different men standing there at the end of it. The kind of weight you lose is decided by whether you are lifting while it comes off.
All of it rests on one thing being true on the day. The load has to be genuinely heavy for you, on that exercise, in that session. Heavy enough builds muscle. A little under is a workout you feel tomorrow, and from the outside those two sets look identical.
The whole gym runs on an AI-based strength measurement system. It reads exactly what level of effort you are putting in on this repetition, today, and keeps the weight in the range that builds strength and muscle rather than the range that only makes you tired. No junk reps.
What we measure here is strength, body composition, grip strength, resting heart rate, balance and posture. Your hormone panel stays with your physician. Any gym in La Habra can hand you a dumbbell. Not one of them can tell you whether the set you just finished was heavy enough to count, while the weight is still in your hands, and when you are building muscle without much help from your hormones, every set has to count.
Twenty-five minutes. No charge. You walk out with your numbers.
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