Normal vs. Athletic: Reference Ranges Compared

eGFR is not actually measured: it is calculated from your serum creatinine level. Creatinine is a waste product of muscle metabolism. The more muscle you carry, the more creatinine your body produces, and the lower your calculated eGFR drops.

The creatinine equation most labs use, the MDRD or CKD-EPI formula, incorporates age, sex, and race, but not lean body mass. For a 100 kg bodybuilder at 10% body fat, serum creatinine often sits between 1.4 and 1.6 mg/dL, which crunches to an eGFR around 60 to 70. That is not kidney damage. The same creatinine in a sedentary 60 kg woman would indicate real renal impairment. Cystatin C bypasses this entirely because it is produced at a constant rate by all nucleated cells and filtered freely by the glomerulus. When cystatin C based eGFR is above 90, you can confidently ignore the creatinine based number. Always ask for both markers on the same draw.

For a strength athlete, an eGFR of 75 mL/min is typically normal physiology, not kidney disease. On AAS, muscle mass increases further, pushing creatinine even higher and eGFR even lower. This is why Cystatin C is so important: it is a kidney function marker that is completely independent of muscle mass. If your Cystatin C is normal, your kidneys are fine regardless of what the creatinine-based eGFR says.

Practical tip: Always request Cystatin C alongside creatinine if you are a strength athlete or AAS user. It prevents unnecessary nephrology referrals.

AST and ALT are present in both liver cells and skeletal muscle cells. When you train hard: especially with heavy compound lifts: you create microtrauma in your muscle fibers. Those damaged muscle cells release AST and ALT into your bloodstream, exactly as liver cells would if you had liver damage.

The key insight is GGT: this enzyme is found in the liver but not in muscle. If your AST and ALT are elevated but your GGT is normal, the source is almost certainly muscle, not liver. CK (creatine kinase) confirms this: a high CK alongside elevated AST/ALT with normal GGT is the classic muscle-leak pattern.

A practical way to separate training leak from liver disease is to look at the AST to ALT ratio and the magnitude of elevation. Muscle injury typically raises AST more than ALT, sometimes pushing the ratio above 2.0, while ALT is more liver specific. A CK above 5000 IU/L with AST under 200 and ALT under 150 points squarely at muscle. On the other hand, a GGT that climbs while you're on an oral is a real hepatic signal worth bringing to a licensed medical professional rather than managing with supplements or a self-directed dose change. Also remember that heavy leg day can keep CK elevated for 5 to 7 days, so time your blood draw at least 72 hours after training.

Oral AAS add a genuine hepatic burden that GGT captures well. If you are on oral compounds and your GGT starts rising, that is a real signal: not training noise.

AAS suppress HDL and raise LDL through multiple mechanisms: increased hepatic lipase activity, altered reverse cholesterol transport, and direct effects on lipid metabolism. The standard "HDL above 40" threshold is almost never met on blast.

The goal on cycle is not to hit the standard lipid panel. Focus on ApoB. A value below 80 mg/dL is considered low risk, but many AAS users run 100 to 130 on blast. The key is the trend: if ApoB rises steadily across cycles and never returns to baseline off cycle, that is cumulative cardiovascular stress worth a real conversation with a licensed medical professional — lipid-lowering medication exists and is something they may consider, but the choice and dose is theirs to make with you, not a self-directed addition. Diet and aerobic work are the lower-risk levers in the meantime: reducing saturated fat and adding regular zone 2 cardio are both associated with more favorable lipid profiles, though they're unlikely to fully offset a strongly lipid-disrupting protocol on their own. Do not panic at a single high LDL reading.

The athletic-adjusted threshold of above 25 mg/dL reflects on-cycle reality while still flagging truly dangerous values. The more important marker is ApoB: it measures the number of atherogenic particles and is a stronger predictor of cardiovascular risk than LDL or HDL in isolation.

AAS stimulate erythropoiesis: your bone marrow produces more red blood cells, and a hematocrit of 50-52% is common on cycle. But the number alone isn't the full risk picture — it becomes a real clotting concern specifically alongside an elevated platelet count and reduced physical activity, and separately it can raise blood pressure, which is what actually strains arteries and kidneys over time. Read it alongside platelets, blood pressure, and training, not in isolation.

The standard range upper limit of 50% would flag almost every AAS user as abnormal, creating unnecessary alarm. That said, once hematocrit climbs well above that range, sustained blood viscosity is a genuine cardiovascular concern worth a licensed medical professional's attention regardless of the underlying cause.

A persistently elevated hematocrit is a result to bring to a licensed medical professional rather than self-manage. Phlebotomy is a standard clinical response, but it treats the reading rather than the driver — ferritin needs checking first, since repeated donation can deplete iron stores and cause its own fatigue independent of hematocrit. Whether the better lever is phlebotomy, a dose change, or something else depends on the full picture, which is exactly why it's a decision to make with whoever manages your protocol rather than a self-directed plan.

Total testosterone on cycle ranges from supraphysiological to suprapharmacological. Standard ranges simply have no concept for this: they are designed for natural production. SHBG is pharmacologically suppressed by AAS in a dose-dependent manner. E2 rises proportionally to T via aromatase. These are expected pharmacological effects, not pathological findings.

On a typical cycle of 500 mg testosterone enanthate per week, total testosterone often peaks at 3000 to 4000 ng/dL, far above the standard range of 300 to 1000. SHBG drops to 10 to 15 nmol/L, which increases free testosterone even further. E2 usually lands between 60 and 120 pg/mL, which many athletes tolerate without issues. The problem is when E2 climbs high enough to bring real symptoms: bloating, high blood pressure, and gynecomastia risk. That combination is worth bringing to whoever manages your protocol — an aromatase inhibitor is a standard option they may consider, but the drug, dose, and timing are a prescribing decision, not something to self-start. Crashing E2 too low carries its own real costs (joint pain, mood swings, poor lipid profiles), which is exactly why AI use needs guidance rather than a fixed rule. The athletic reference range for E2 is roughly 30 to 80 pg/mL on cycle.