Blood Marker Reference

Total testosterone is the primary metric for dose titration on TRT. Levels above 1100 ng/dL substantially increase aromatization to estradiol and raise hematocrit, while levels below 600 ng/dL often fail to resolve hypogonadal symptoms.

Free testosterone is the biologically active fraction that binds androgen receptors. It correlates more closely with symptom relief, libido, energy, and body composition changes than total testosterone.

Estradiol is the primary estrogen in males and mediates bone density, cardiovascular health, libido, and mood. On TRT, elevated testosterone increases aromatase activity, often driving E2 above range.

Hematocrit measures the proportion of red blood cells in blood. Testosterone directly stimulates erythropoiesis, making hematocrit rise the most common TRT-related safety concern — elevated levels increase blood viscosity and clotting risk.

Hemoglobin tracks in parallel with hematocrit and reflects oxygen-carrying capacity. On TRT and AAS, it rises alongside hematocrit and provides a complementary view of erythrocytosis risk.

HbA1c reflects average blood glucose over 90 days and is the key marker for insulin sensitivity. AAS — particularly 17-alpha alkylated orals and high-dose testosterone — can impair insulin sensitivity, gradually pushing HbA1c upward.

AST is an enzyme found in both liver and muscle tissue. On TRT and injectable AAS, AST elevation is often of skeletal-muscle origin (training-related) rather than hepatic, making ALT/AST ratio and GGT critical for distinguishing true liver stress.

ALT is more liver-specific than AST and is the primary marker for hepatocellular damage. Elevated ALT on oral AAS is a direct signal of hepatic stress and requires dose reduction or cycle termination if values exceed 3× upper limit of normal.

HDL ('good' cholesterol) is the most consistently suppressed cardiovascular marker on AAS. Even low-dose TRT reduces HDL, and oral or high-dose anabolic cycles can drop HDL below 30 mg/dL — a range associated with significantly elevated coronary artery disease risk.

LDL is the primary driver of atherosclerotic plaque formation. AAS commonly raise LDL while suppressing HDL, creating a doubly atherogenic lipid profile. The combination with elevated hematocrit significantly amplifies cardiovascular risk.

ApoB (apolipoprotein B) counts every atherogenic lipoprotein particle — including LDL, VLDL, and IDL. It is a more accurate cardiovascular risk predictor than LDL-C, especially for AAS users who often have discordant LDL and particle counts.

Sex hormone-binding globulin (SHBG) binds testosterone, determining how much free (active) testosterone is available. Low SHBG means more free T per dose — but also faster clearance, making injection frequency critical. High SHBG blunts TRT efficacy.