The short version
- The Endocrine Society's 2018 guideline advises diagnosing testosterone deficiency only in men with consistent symptoms plus a fasting morning total testosterone confirmed by repeating the measurement.
- In 890 men followed by the Baltimore Longitudinal Study of Aging, total testosterone fell about 0.124 nmol/L per year, and the hypogonadal-range proportion reached roughly 20% over 60 and 50% over 80.
- Age-standardised prediabetes prevalence among US adults rose from 29.5% in 1999 to 48.3% by 2018 across 21,600 people, which makes HbA1c and fasting glucose the highest-value cheap numbers on a panel.
- Among 13,015 statin-treated patients, high apolipoprotein B tracked with all-cause mortality and myocardial infarction where high LDL cholesterol did not, at hazard ratios of 1.21 and 1.49.
- A blood panel interpreted by a doctor costs less than two months of most supplement stacks and tells you which problem you actually have before you start buying answers.
You are somewhere past forty. The weight settled differently than it used to. You are flat by three in the afternoon, the last set feels heavier than the log says it should, and you have started reading supplement labels late at night. Here is what a supplement company is not supposed to tell you: the highest-return purchase available to you right now is a blood draw, and it costs less than two months of most stacks.
Not because supplements are useless. Because you do not currently know which problem you have, and everything on our shelf is an answer to a specific question. Buying answers before you have the question is how men end up with eleven bottles and the same Tuesday afternoon.
Testosterone, and the way most men get it measured wrong
The Endocrine Society's 2018 clinical practice guideline is unusually specific about this, and almost nobody follows it. Their recommendations, in order:
- Diagnose testosterone deficiency only in men who have symptoms and signs consistent with it and unequivocally, consistently low serum testosterone.
- Measure fasting morning total testosterone, using an accurate and reliable assay, as the initial diagnostic test.
- Confirm by repeating the morning fasting measurement. One draw is not a diagnosis.
- If total testosterone is near the lower limit of normal, or something is altering sex hormone-binding globulin, obtain free testosterone by equilibrium dialysis or an accurate calculation.
- If deficiency is confirmed, carry out further evaluation to establish why.
Translate that into what actually happens. A single non-fasting afternoon testosterone from a walk-in panel is not a result you can act on, and the number genuinely moves depending on when you sat down. If you are going to test, test properly — morning, fasted, twice. And notice that the guideline's insistence on finding the cause is exactly the step direct-to-consumer testing skips, because "here is your number, here is our subscription" is a faster business.
What ageing actually does to that number
The Baltimore Longitudinal Study of Aging followed 890 men and modelled the change over time. Harman and colleagues reported significant, independent, age-invariant longitudinal declines in both total testosterone and the free testosterone index — an average change of about −0.124 nmol/L per year for total testosterone. The proportion of men with total testosterone in the hypogonadal range reached roughly 20% over age 60, 30% over 70 and 50% over 80. Total testosterone also decreased as body mass index rose.
Two things to take from that. The decline is slow and gradual, so a sharp drop is a reason to ask a doctor why, not a reason to open a browser tab. And BMI sits inside the model — body composition is not a separate conversation from this one, it is part of it.
The boring panel that matters more
An analysis of NHANES data across 21,600 US adults found that the age-standardised prevalence of prediabetes rose from 29.5% in 1999 to 48.3% by 2018, with total diabetes rising from 9.17% to 14.7% and undiagnosed diabetes holding roughly steady between 3% and 3.7%. Close to half of adults met a prediabetes threshold by the end of that window.
HbA1c and fasting glucose are cheap, they sit on almost every basic panel, and knowing them tells you more about how your next twenty years are likely to go than any hormone on the sheet. We are not going to tell you that a supplement changes those numbers. We are telling you to know them, and to know them from a doctor who will do something with the information.
The lipid marker your standard panel probably left off
Johannesen and colleagues followed 13,015 statin-treated patients in the Copenhagen General Population Study for a median of eight years. High apolipoprotein B and high non-HDL cholesterol were associated with increased risk of all-cause mortality and myocardial infarction — while high LDL cholesterol was not. Where apoB sat above the median but LDL cholesterol sat below it, the hazard ratios were 1.21 (95% CI 1.07–1.36) for all-cause mortality and 1.49 (95% CI 1.15–1.92) for myocardial infarction.
Be precise about that population: patients already on statin therapy, so the finding is about residual risk rather than a general screening recommendation. But it is a solid reason to ask your doctor whether apoB belongs on your panel, particularly if your LDL "looks fine" and there is heart disease in your family. It is an inexpensive addition to a standard lipid panel and most labs will run it on request.
The rest of the sheet
Worth asking your doctor about, especially if fatigue is your main complaint: a full blood count, ferritin, thyroid function, vitamin D, and liver and kidney function. That last pair matters for a specific reason. You are about to start putting things into your body, and knowing your baseline before you do is simply better practice than finding out afterwards.
What we'd actually tell you
Go to a doctor rather than a direct-to-consumer panel if you possibly can. The number is the easy part. Interpreting it against your symptoms, your medications and your history is what you are actually paying for, and it is the part the subscription model leaves out.
Get it drawn in the morning, fasted. If testosterone is the question, get it drawn twice. Then take the results back before you buy anything, from us or from anyone. A great deal of what men attribute to age turns out to be short sleep, a rising A1c, a medication side effect, or a thyroid worth looking at — and none of those are things a capsule from our shelf is the right answer to.
And the line we will keep repeating, because it is the whole point of writing this: if your labs come back abnormal, that is a medical situation with medical management. Supplements support normal function. They are not treatment, they are not a diagnosis, and any brand that blurs that boundary should be held to it. Including us. Especially us.
Good questions
What blood tests should a man over 40 actually get?
Start with the boring ones. HbA1c and fasting glucose sit on almost every basic panel and tell you more about your next twenty years than any hormone on the sheet. Worth asking your doctor about alongside them: a full blood count, ferritin, thyroid function, vitamin D, and liver and kidney function, particularly if fatigue is your main complaint and you are about to start taking things.
What time of day should testosterone be measured?
Morning, fasted, and then again on a second morning. The Endocrine Society guideline names fasting morning total testosterone as the initial diagnostic test and specifically recommends confirming it by repeating the measurement. A single non-fasting afternoon draw from a walk-in panel is not a result you can act on, because the number genuinely moves depending on when you sat down.
Are direct-to-consumer blood test panels worth the money?
Go to a doctor first if you possibly can. The number is the easy part; interpreting it against your symptoms, medications and history is what you are actually paying for. The guideline's insistence on establishing why a level is low is exactly the step consumer testing skips, because handing you a number and a subscription is a faster business than finding a cause.
Is my testosterone low, or am I just getting older?
Ageing moves it slowly. The Baltimore Longitudinal Study of Aging measured an average decline of about 0.124 nmol/L a year in 890 men, so a sharp drop is a reason to ask a doctor why rather than to open a browser tab. Body mass index sat inside the same model too, which means body composition is part of this conversation rather than a separate one.
Should I ask for an apoB test?
It is worth asking, especially if your LDL looks fine and heart disease runs in your family. In 13,015 statin-treated patients followed a median of eight years, high apoB tracked with mortality and heart attack where LDL did not. Be precise about that population though: these were people already on statins, so the finding is about residual risk, not general screening. It is an inexpensive addition to a lipid panel.
Can supplements fix an abnormal blood test result?
No. If your labs come back abnormal, that is a medical situation with medical management. Supplements support normal function; they are not treatment and they are not a diagnosis. A great deal of what men attribute to age turns out to be short sleep, a rising A1c, a medication side effect or a thyroid worth looking at, and none of those are things a capsule from our shelf answers.
Sources
- Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab, 2018. View study
- Harman SM, Metter EJ, Tobin JD, et al. Longitudinal effects of aging on serum total and free testosterone levels in healthy men. Baltimore Longitudinal Study of Aging. J Clin Endocrinol Metab, 2001. View study
- Liu J, Yi SS, Russo R, et al. Trends and disparities in diabetes and prediabetes among adults in the United States, 1999-2018. Public Health, 2023. View study
- Johannesen CDL, Mortensen MB, Langsted A, Nordestgaard BG. Apolipoprotein B and Non-HDL Cholesterol Better Reflect Residual Risk Than LDL Cholesterol in Statin-Treated Patients. J Am Coll Cardiol, 2021. View study
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
