Testosterone replacement therapy requires regular blood work. The Endocrine Society and American Urological Association both emphasize that monitoring isn't optional. It's how you ensure TRT is working safely.
Why TRT Monitoring Matters
TRT affects more than just testosterone levels. It influences red blood cell production, estrogen levels, prostate tissue, liver function, and cholesterol. Monitoring allows your provider to:
- Confirm testosterone is reaching therapeutic levels.
- Catch side effects before they become problems.
- Adjust dosing for optimal results.
- Track markers that affect long-term health.
Men on TRT who skip monitoring risk issues like elevated hematocrit (thickened blood), undetected prostate changes, or suboptimal hormone levels that don't improve symptoms.
The Core TRT Blood Test Panel
Most TRT monitoring panels include several tests. Here's what each one measures and why it matters.
Total and Free Testosterone
What it measures: Total testosterone includes all testosterone in your blood (bound and unbound). Free testosterone measures only the unbound portion that's biologically active.
Why it matters on TRT: These tests confirm that therapy is raising your levels into the target range. The goal is typically mid-normal (around 450-600 ng/dL for total testosterone), though your provider may adjust based on symptoms.
What to watch for: Levels that are too low mean the dose isn't sufficient. Levels that are too high (above 1000-1200 ng/dL) may increase side effects without additional benefit.
Hematocrit and Hemoglobin (CBC)
What it measures: Hematocrit is the percentage of red blood cells in your blood. Hemoglobin is the oxygen-carrying protein inside those cells. Both are part of a complete blood count (CBC).
Why it matters on TRT: Testosterone stimulates red blood cell production. This is usually beneficial, but too many red blood cells thicken the blood and increase clotting risk. According to the Endocrine Society guidelines, hematocrit above 54% requires intervention.
What to watch for: Hematocrit climbing above 50% is a warning sign. Above 54% typically requires dose reduction, temporary pause, or therapeutic phlebotomy (blood donation).
Prostate-Specific Antigen (PSA)
What it measures: PSA is a protein produced by the prostate. Elevated levels can indicate prostate enlargement, inflammation, or cancer.
Why it matters on TRT: Testosterone can stimulate prostate tissue. While research hasn't shown TRT causes prostate cancer, monitoring PSA helps catch any changes early.
What to watch for: A confirmed PSA increase greater than 1.4 ng/mL within the first 12 months, or PSA above 4.0 ng/mL, requires urological evaluation. Men over 40 should have baseline PSA measured before starting TRT.
Estradiol (E2)
What it measures: Estradiol is the primary form of estrogen in men. It's produced when testosterone converts to estrogen through a process called aromatization.
Why it matters on TRT: Higher testosterone levels can lead to higher estradiol. Elevated estradiol can cause water retention, mood changes, and breast tissue growth (gynecomastia).
What to watch for: Estradiol above 40-50 pg/mL may require attention, especially if accompanied by symptoms like breast tenderness, puffiness, or mood issues. Some men function well at higher levels; symptoms matter more than the number alone.
Lipid Panel
What it measures: Total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides.
Why it matters on TRT: Testosterone therapy can affect cholesterol, particularly HDL (the "good" cholesterol). Higher doses are more likely to lower HDL.
What to watch for: Significant drops in HDL or increases in LDL warrant discussion with your provider about cardiovascular risk management.
Comprehensive Metabolic Panel (CMP)
What it measures: Liver enzymes (ALT, AST), kidney function markers (creatinine, BUN), blood glucose, and electrolytes.
Why it matters on TRT: Oral testosterone (rare in the US) can affect liver function. Injectable and topical testosterone don't typically cause liver issues, but monitoring ensures no unexpected changes occur.
What to watch for: Significant elevations in liver enzymes require further evaluation. For more on liver markers, see our liver function testing guide.
TRT Bloodwork Schedule
Guidelines from major medical organizations recommend a specific testing timeline:
Timeframe
Tests Recommended
Baseline (before TRT)
Total testosterone (2 morning samples), free testosterone, CBC, PSA (men over 40), lipid panel, CMP
3-6 months
Total/free testosterone, hematocrit, PSA
12 months
Total/free testosterone, hematocrit, PSA, lipid panel, CMP
Annually (once stable)
Total/free testosterone, hematocrit, PSA, lipid panel
Some providers test more frequently during the first year, especially if adjusting doses or if baseline hematocrit was elevated.
When to Time Your Blood Draw
Timing matters for accurate TRT labs.
Morning draws are essential. Testosterone levels fluctuate throughout the day, peaking in the morning. Test between 7-10 AM for consistency.
For injectable testosterone:
- If taking weekly injections, test mid-cycle (3-4 days after injection) for a representative level.
- Testing at trough (just before your next injection) shows your lowest level.
- Your provider may request one or both depending on symptoms.
For gels or patches:
- Test 2-4 hours after application for peak levels.
- Or test before application for trough levels.
Consistency is key. Test at the same time relative to your dosing schedule so results can be compared accurately over time.
Red Flags That Require Attention
Contact your provider if labs show:
- Hematocrit above 54% - Requires dose reduction or phlebotomy.
- PSA increase >1.4 ng/mL in the first 12 months.
- PSA above 4.0 ng/mL - Needs urological evaluation.
- Testosterone levels well above 1000 ng/dL without symptom improvement.
- Estradiol above 50 pg/mL with symptoms (breast tenderness, water retention, mood changes).
- Significant liver enzyme elevation - Especially if using oral testosterone.
These findings don't necessarily mean stopping TRT. They signal that adjustments or additional evaluation may be needed.
Additional Tests in Specific Situations
Some men need extra monitoring:
LH and FSH - Usually only checked at diagnosis. On TRT, these will be suppressed (low) because external testosterone tells the brain to stop signaling the testes. Low LH/FSH on TRT is expected, not concerning.
Prolactin - Checked if testosterone remains low despite adequate dosing, or if symptoms suggest pituitary issues.
SHBG (Sex Hormone Binding Globulin) - Affects how much testosterone is available. Useful if symptoms don't match testosterone levels.
Thyroid function - If fatigue or other symptoms persist despite optimal testosterone levels.
At-Home TRT Monitoring
Traditional lab monitoring requires scheduling appointments at a clinic or lab. At-home testing offers a convenient alternative for ongoing monitoring.
At-home TRT panels typically include:
- Total and free testosterone.
- Hematocrit/hemoglobin.
- PSA.
- Estradiol.
- Basic metabolic markers.
The process is straightforward: collect a morning blood sample via finger prick, mail it to a certified lab, and receive results online within a few days.
At-home testing is useful for tracking trends between clinic visits. For comprehensive management, you'll still want periodic in-person evaluations, but at-home panels can supplement your monitoring schedule and catch changes between appointments.
FAQ
How often should I get blood work on TRT? Ideally 3-6 months after starting, at 12 months, then annually. More frequent testing may be needed if adjusting doses or if labs show concerning trends.
Can I skip monitoring if I feel fine? No. Some TRT side effects (like elevated hematocrit) don't cause symptoms until they become serious. Labs catch problems before you feel them.
What if my testosterone is high but I still have symptoms? This can happen if free testosterone is low due to high SHBG, or if other hormones (thyroid, estradiol) are out of balance. Additional testing can help identify the issue.
Do I need to fast for TRT labs? Fasting isn't required for testosterone or hematocrit, but it is recommended if your panel includes a lipid profile or glucose testing.
Consistent monitoring is what separates safe, effective TRT from guesswork. The tests aren't complicated, and the information they provide helps you and your provider optimize treatment while minimizing risks.
Can I drink alcohol on TRT?
Yes, you can consume alcohol on Testosterone Replacement Therapy (TRT), however limiting consumptoin as much as possible is advisable. This is because heavy drinking directly counteracts the treatment by lowering testosterone, raising estrogen, and taxing the liver. Excessive alcohol can cause fatigue, reduced muscle mass, and lowered libido, negating the benefits of TRT. Read more on the interplay between alcohol and testosterone here.
This article is for educational purposes only and is not medical advice. Work with a healthcare provider to develop a monitoring plan appropriate for your situation.
