Your biomarkers. Your nights. Your firmest, fittest self.

Why it matters.

Testosterone builds and maintains the male body. It governs muscle mass and bone density, red blood cell production, and where you store fat. It drives libido, erectile function, motivation, mood, and how well you sleep. When a man says he feels flat, soft, tired, and slower than he used to be, he is describing a cluster of things this one hormone touches.

Levels fall by roughly one percent a year from the thirties onward. The decline is slow enough that most men credit it to age, to work, or to stress, and never think to check.

Why it matters.

Only a small fraction of your testosterone is free to act. The rest travels bound to carrier proteins, which keeps it stable in the bloodstream but unavailable to the muscle, bone, brain, and vascular tissue that respond to it. Free testosterone is the portion your body can use today. Because of that, free testosterone often tracks symptoms more closely than total does. A man with a mid-range total and a low free result is a common presentation in men's health, and one a total-only panel misses entirely.

Why it matters.

SHBG is the protein that determines how much of your testosterone stays in reserve. It binds tightly, and testosterone bound to SHBG cannot act on tissue. A man with high SHBG can post a healthy total while relatively little of it is available to him. A man with low SHBG can post a modest total and have more in circulation than the number suggests.

SHBG also moves for reasons worth knowing. It rises with age and with thyroid activity, and it falls with insulin resistance, excess weight, and higher androgen levels.

Why it matters.

Your testes are not your only source of androgens. DHEA-S reports what your adrenal glands contribute, which gives a second and independent view of production. It peaks in a man's twenties and falls steadily from there, more predictably than testosterone does. Read beside your testosterone result, DHEA-S shows whether a low figure reflects one system or two, and that distinction changes what your coach recommends.

Why it matters.

Men need estrogen. Estrogen is not only a female hormone. Men convert a portion of their testosterone into estradiol through an enzyme called aromatase, and men need the result. Estradiol supports bone density, libido, erectile function, and mood. Men whose estradiol runs too low often report joint discomfort, flat libido, and low mood, which are the same complaints they may have blamed on testosterone.

Why it matters.

LH is the most interpretively useful marker on this panel, because it shows where in the chain a low result begins. Low testosterone with high LH means the signal is being sent loudly and the testes are not answering. Low testosterone with low or normal LH means the signal itself is quiet. Those are two different situations with two different sets of next steps, and a testosterone figure alone cannot tell them apart.

Why it matters.

FSH and LH leave the same gland and travel the same path, so reading them together shows whether pituitary signaling is intact across the board or disturbed selectively. FSH also carries direct relevance for any man weighing fertility, now or later.

Why it matters.

Total cholesterol is broad and blunt, and on its own it says little. A good figure can hide a poor distribution; a high one can reflect a large and protective HDL fraction. It earns its place as context for the five markers around it rather than as a verdict of its own. Read it last, not first.

Why it matters.

Total cholesterol sums the cholesterol carried across every particle in your blood, and that summing is both its use and its limitation. It gives one figure for how much cholesterol is in circulation. HDL is the traffic running in the useful direction. Higher figures are generally read as favorable, and HDL responds to the things a coaching program can actually change: regular training, alcohol intake, and body composition. It is among the more responsive markers here, which makes it a practical one to retest against.

Why it matters.

LDL is the number most men have been told to watch, and it deserves the attention it gets. LDL particles carry cholesterol out to your tissue, and they are the particles that deposit cholesterol into artery walls when they linger in circulation. That deposition, accumulated over decades, is what narrows arteries, including the smaller arteries involved in erectile function. LDL as reported here is calculated, and it estimates how much cholesterol those particles carry rather than how many particles are present.

Why it matters.

Triglycerides move fast and respond hard. Diet, alcohol, and insulin resistance all push them, and few markers here react as quickly to a change in habits, which makes them a strong short-term signal that a plan is working. High triglycerides paired with low HDL is a recognized metabolic pattern, and your coach will look for it specifically, since this panel carries no dedicated blood sugar marker.

Why it matters.

Every particle capable of depositing cholesterol into an artery wall carries exactly one ApoB molecule. Measuring ApoB therefore counts those particles directly, rather than estimating how much cholesterol they hold.

That distinction has consequences. Particle count predicts cardiovascular risk more reliably than LDL cholesterol does, and the two can disagree: a man with many small, cholesterol-poor particles can post a reassuring LDL while carrying elevated risk. Specialists have moved toward ApoB for this reason, and it remains uncommon on a standard annual physical.

Why it matters.

Lp(a) finds the man who has done everything right. Diet moves it very little. Training moves it very little. A man can post an immaculate lipid panel and still carry an elevated Lp(a) inherited from a parent, and he will never know unless somebody measures it, which most panels never do. Because the value is largely fixed at birth, a single measurement usually answers the question for life. Knowing it changes how aggressively the rest of this panel is worth managing.

Why it matters.

Creatinine is a waste product your muscles generate continuously and your kidneys clear from the blood. When filtration slows, creatinine accumulates, which makes it a long-standing measure of kidney function. Kidney function matters on this panel for two reasons: it regulates blood pressure, which bears directly on vascular health, and it determines how your body clears medications and supplements.

Creatinine has one well-documented limitation. Because it originates in muscle, a man with high muscle mass produces more of it, and his result can read as elevated while his kidneys function normally. That limitation is why this panel includes a second, independent measure.

Why it matters.

Cystatin C is produced at a constant rate by nearly every nucleated cell in your body and cleared almost entirely by your kidneys. Production does not vary with muscle mass, diet, or training, so it avoids the confounding that affects creatinine.

For a man who lifts or carries above-average muscle, cystatin C is generally the more accurate estimate of filtration. Measuring both is what makes the result trustworthy: agreement between them confirms the reading, and disagreement usually points to muscle mass rather than to a kidney problem.

Why it matters.

eGFR turns a protein value into a rate, which turns an abstraction into something you can hold onto and track. Basing it on cystatin C rather than creatinine keeps muscle mass out of the calculation entirely. This is the single number to watch across retests, and a steady eGFR over years is worth more than any one reading.

Why it matters.

Albumin does double duty here. It reflects how well your liver builds protein and how well you are nourished, and it binds testosterone loosely, unlike SHBG, so albumin-bound testosterone stays partly available to your tissue. That loose binding is why albumin feeds directly into your free testosterone calculation. A marker filed under liver function is quietly shaping your hormone result.

Why it matters.

ALT responds to alcohol, to prescription medications, and to supplements, including several marketed specifically to men for training and performance. It also tends to rise with fat accumulation in the liver, a condition tied closely to insulin resistance, and insulin resistance is among the most common upstream drivers of low testosterone. On a panel carrying no dedicated blood sugar marker, ALT is the closest indirect window into that picture.