How to Prepare for a Testosterone Blood Test: Do’s and Don’ts
Testing your testosterone levels is a crucial step in diagnosing hormonal imbalances and understanding your overall health. However, certain factors can affect the accuracy of your testosterone test, so proper preparation is essential.
We'll cover some of the best practices for preparing for a testosterone blood test, including fasting requirements, the best time to test, medications that may interfere, and lifestyle factors that can impact your results.
Why Preparation Matters for a Testosterone Blood Test
Testosterone levels fluctuate throughout the day and can be influenced by food, stress, sleep, and medications. Without proper preparation, you may receive misleading results, leading to an incorrect diagnosis or unnecessary treatment.
By following these guidelines, you can ensure that your testosterone test results are as accurate and reliable as possible.
Step 1: Choose the Right Time for Your Testosterone Test
Test in the Morning for Best Accuracy
Testosterone levels follow a circadian rhythm, meaning they are highest in the morning and decline throughout the day.
✅ Best time to test: Between 7:00 AM and 10:00 AM [¹].
⚠️ After 10:00 AM, levels can drop, leading to potentially misleading low results.
💡 Tip: If you're over 50, this fluctuation is less pronounced, but morning testing is still recommended for consistency.
Step 2: Do You Need to Fast Before a Testosterone Test?
Fasting Recommendations
- Some labs recommend fasting for 8-12 hours before a testosterone test.
- Eating high-fat meals before the test can alter hormone levels by affecting insulin and cortisol, which interact with testosterone [²].
- Water is allowed during fasting.
🔹 Best Practice: If fasting is recommended, schedule your test early in the morning before breakfast.
Step 3: Avoid Certain Medications & Supplements
Some medications and supplements can artificially raise or lower testosterone levels.
If you're taking any of the following, inform your doctor before testing:
Medications That May Lower Testosterone:
❌ Opioids (pain medications)
❌ Corticosteroids (Prednisone, Hydrocortisone)
❌ Anti-anxiety or antidepressants (SSRIs, Benzodiazepines)
❌ Statins (cholesterol-lowering drugs)
Medications That May Increase Testosterone:
✔️ Testosterone Replacement Therapy (TRT)
✔️ Anabolic steroids (often used for bodybuilding)
✔️ Certain supplements (DHEA, Ashwagandha, Fenugreek)
💡 Tip: Avoid taking testosterone-boosting supplements or TRT for at least 24-48 hours before testing unless instructed otherwise by your doctor [³].
Step 4: Get a Good Night’s Sleep
Testosterone production occurs during deep sleep (especially REM sleep). Poor sleep can significantly lower testosterone levels the next morning [⁴].
✅ Aim for at least 7-9 hours of quality sleep the night before your test.
❌ Avoid alcohol and caffeine before bed, as they can disrupt sleep cycles.
Step 5: Reduce Stress Before the Test
Chronic stress raises cortisol levels, which inhibits testosterone production.
✅ Engage in stress-reducing activities (meditation, deep breathing, light exercise) the night before.
❌ Avoid intense workouts the morning of the test, as excessive exercise can temporarily lower testosterone levels [⁵].
Step 6: Avoid Heavy Exercise Before the Test
🚫 Why? Strenuous exercise (especially heavy weightlifting or endurance training) can cause temporary testosterone fluctuations.
✅ If you regularly work out, skip intense exercise 24 hours before testing to avoid skewing results.
💡 Light activity like walking or yoga is fine.
Step 7: Stay Hydrated
✅ Drink plenty of water before the test to ensure a smooth blood draw and prevent dehydration, which can affect hormone levels.
❌ Avoid sugary drinks and excessive caffeine, as they can cause insulin spikes, indirectly affecting testosterone.
Step 8: Know What Other Hormones Might Be Tested
A testosterone test is often done alongside other hormone tests for a full picture of hormonal health:
✔️ Free vs. Total Testosterone – Measures both bound and unbound testosterone.
✔️ Sex Hormone-Binding Globulin (SHBG) – Helps assess available testosterone levels.
✔️ Luteinizing Hormone (LH) – Determines if low testosterone is due to a pituitary issue.
✔️ DHT (Dihydrotestosterone) – A more potent androgen derived from testosterone.
✔️ Estradiol (E2) – High estrogen levels in men can indicate hormonal imbalances.
💡 Tip: Ask your doctor if a comprehensive hormone panel is needed.
Summary: Testosterone Test Preparation Checklist
✅ Test between 7-10 AM for most accurate results.
✅ Fast for 8-12 hours if required by your doctor.
✅ Inform your doctor about medications that may affect results.
✅ Get 7-9 hours of quality sleep the night before.
✅ Avoid strenuous exercise 24 hours before the test.
✅ Manage stress levels to reduce cortisol.
✅ Stay hydrated with water (no sugary or caffeinated drinks).
By following these steps, you can ensure your testosterone blood test provides accurate results, leading to better-informed decisions about your health.
Footnotes & Citations
- The Endocrine Society. “Testosterone Testing Recommendations.” Journal of Clinical Endocrinology & Metabolism, 2018. Available here
- Mayo Clinic. “Fasting and Hormone Blood Tests: What You Need to Know.” Mayo Clinic, 2022. Available here
- American Urological Association. “Factors That Affect Testosterone Test Accuracy.” AUA Guidelines, 2019. Available here
- Leproult, R., et al. “Impact of Sleep Deprivation on Testosterone Levels.” JAMA, 2011. Available here
- Kraemer, W.J., et al. “The Effects of Resistance Training on Hormonal Response.” Journal of Strength & Conditioning Research, 2021. Available here
