Testosterone replacement therapy is an important treatment option for men with low testosterone and symptomatic hypogonadism. Various formulations of exogenous (supplemental) testosterone replacement therapy exist, including oral, buccal, intramuscular, transdermal, subdermal, and nasal preparations. However, exogenous testosterone replacement therapy is a double-edged sword, posing risks to fertility due to negative feedback mechanisms on the hypothalamic-pituitary-gonadal (HPG) axis, which is the primary regulator of testosterone production and sperm production in men. 

Testosterone replacement therapy (TRT) is one of the most effective ways to combat low testosterone levels, but you must understand the risks associated with the treatment. As with any hormone replacement therapy, there are a few downsides to receiving regular testosterone injections. But do these risks outweigh the benefits? That’s a decision you’ll have to make for yourself!


Testosterone replacement therapy- Target Blood Test Limits:

To minimize TRT side effects, different medical guideline groups have created lab test value ranges and maximum acceptable targets .

These values have been collected from three TRT guidelines and clinical practices around the United States:

  • Hematocrit (percent of red blood cells in plasma) under 53
  • PSA (Prostatic specific antigen) under 3 (4 is max since doctors will not prescribe TRT at this number)
  • Estradiol (sensitive) between 20-50 pg/mL. However, if you have high testosterone, estradiol will be "high" per Quest or Labcorp since 0.4% of total testosterone aromatizes to estradiol.
  • Blood pressure under 135/85
  • Estimated Glomerular (eGFR) (kidney function) over 60
  • Liver enzymes not elevated over 20 percent of top value of reference range
  • Total Testosterone over 450 ng/dL
  • Free Testosterone equal or above 2 percent of total
  • If donating blood to bring hematocrit down, ferritin should never under 30 ng/mL or micrograms/liter (this could lead to fatigue)
  • Free T3 (if hypothyroid and on treatment) in the upper quartile of range. (depending on range it can be 3.7- 4.2 pg/mL)
  • HDL over 40 mg/dL (higher TRT doses can lead to decreased HDL cholesterol)

You can order these lab tests here:

TRT Male Hormone/Wellness Follow-Up Panel


Lipid Panel

Thyroid Panel