What not to do before a testosterone blood test? Your guide to accurate results

October 13, 2025 •

5 min read

According to MedlinePlus, for a total testosterone test, the sample is often taken in the morning to capture peak levels. However, many factors can interfere with your results, which is why it is critical to know what not to do before a testosterone blood test.

Quick Summary

Preparing for a testosterone blood test requires careful attention to timing and certain lifestyle habits to ensure accurate results. Avoid strenuous exercise, alcohol, and stress, and follow specific fasting guidelines. Always inform your doctor about your medications and supplements before your test.

Key Points

Timing Is Key: Testosterone levels are highest in the morning, so schedule your test between 7 a.m. and 10 a.m. for the most accurate baseline reading.
Avoid Strenuous Exercise: Refrain from intense workouts for at least 24-48 hours before your test, as it can cause temporary fluctuations in hormone levels.
Skip the Alcohol: Alcohol consumption within 24 hours of your test can disrupt hormone levels and alter other markers, potentially leading to inaccurate results.
Be Aware of Medications: Inform your doctor about all medications and supplements, as many can interfere with testosterone levels. Never stop a prescribed drug without medical advice.
Prioritize Sleep and Stress Management: Ensure 7-9 hours of quality sleep and manage stress levels the night before your test to avoid artificially low testosterone readings.
Follow Fasting Instructions: Adhere strictly to any fasting guidelines provided by your doctor or lab, typically involving refraining from food for 8-12 hours while drinking only water.
Hydrate with Water: Staying well-hydrated makes the blood draw process smoother and helps maintain consistent blood volume.

The Importance of Accurate Results

A testosterone blood test measures the amount of the hormone in your bloodstream and is used to diagnose conditions related to low or high levels. Testosterone levels naturally fluctuate throughout the day, with the highest concentrations typically found in the morning. To get a reliable and actionable result, it is essential to minimize external variables that could skew the reading. Incorrect results can lead to misdiagnosis, unnecessary further testing, or inappropriate treatment plans. Therefore, proper preparation is key to ensuring your doctor receives data that accurately reflects your body's true hormonal state.

Key Activities to Avoid Before Your Blood Draw

Don't Exercise Strenuously

While regular exercise is beneficial for overall health and can positively influence hormone levels long-term, intense physical activity just before a blood test can be counterproductive.

Acute Exercise Fluctuation: Strenuous workouts, particularly heavy weightlifting or endurance training, can cause temporary spikes or drops in testosterone levels that do not reflect your baseline.
Inflammatory Markers: Intense exercise can also temporarily increase other markers, such as creatine kinase and liver enzymes, which can complicate the interpretation of your bloodwork.
Recommendation: Avoid strenuous exercise for at least 24 to 48 hours before your test. Light activities, like a gentle walk or stretching, are generally fine.

Don't Drink Alcohol

Alcohol consumption, especially in excess, can negatively impact your test results and overall hormonal health.

Hormonal Disruption: Excessive alcohol can lower natural testosterone production by affecting the liver and other endocrine pathways.
Inaccurate Markers: Alcohol can alter your blood sugar, fat levels, and liver enzymes, potentially affecting the accuracy of a comprehensive hormone panel.
Recommendation: Refrain from drinking any alcohol for at least 24 hours before your blood test.

Don't Take Certain Medications or Supplements

Many prescription drugs and over-the-counter supplements can influence testosterone levels. It is critical to discuss all medications with your doctor before your test. Crucially, never stop taking a prescribed medication without your doctor's explicit instruction.

Medications that may lower testosterone: These include opioids, corticosteroids, some antidepressants (SSRIs), statins, and certain antifungal medications like ketoconazole.
Medications that may increase testosterone: Anabolic steroids and testosterone replacement therapy (TRT) will significantly elevate your levels.
Supplements: Inform your doctor about any supplements you take, as some (like DHEA) can affect hormonal readings.

Avoid Poor Sleep and High Stress

Sleep and stress are major regulators of the body's hormonal systems, and ignoring them can lead to unreliable test results.

Sleep Deprivation: Testosterone levels are highest in the morning because they are produced during sleep. Insufficient or poor-quality sleep can disrupt this natural rhythm and cause a drop in your morning testosterone level.
High Stress: Chronic stress increases the hormone cortisol, which inhibits testosterone production. High stress leading up to your test can therefore give a falsely low reading.
Recommendation: Aim for 7 to 9 hours of quality sleep the night before your test and engage in relaxing, stress-reducing activities.

What About Eating and Drinking?

Most testosterone tests are scheduled in the morning to capture the diurnal peak. Many labs require fasting to prevent food from affecting other markers in a combined blood panel. Follow your doctor's specific fasting instructions, which often mean refraining from eating and drinking anything but water for 8-12 hours beforehand. Staying well-hydrated with water is important for an easier blood draw.

Comparison of Pre-Test Preparation


Factor	What Not To Do (24-48 Hours Before)	What To Do (24-48 Hours Before)
Timing	Get tested in the afternoon or evening (especially if under 45).	Schedule your test between 7 a.m. and 10 a.m..
Exercise	Engage in strenuous weightlifting or endurance workouts.	Stick to light activities like walking, or rest completely.
Alcohol	Drink alcoholic beverages.	Avoid alcohol completely.
Medications/Supplements	Start a new supplement or stop a prescribed medication without consulting your doctor.	Inform your healthcare provider of all medications and supplements you take.
Sleep	Get less than 7 hours of sleep.	Aim for 7-9 hours of quality sleep.
Stress	Engage in high-stress activities.	Use meditation or deep breathing to manage stress.
Eating	Eat a large meal or snack before the test, if advised to fast.	Follow fasting instructions (usually 8-12 hours). Drink water only.

Practical Tips for Your Test Day

Confirm Appointment Details: Reconfirm the time and location of your test. If you are uncertain about fasting or medication rules, call the lab or your doctor's office to clarify.
Stay Hydrated: Drink plenty of water in the hours leading up to your test, as this makes the blood draw easier for the phlebotomist.
Wear Comfortable Clothing: Choose loose-fitting clothes with sleeves that can be easily rolled up to allow access to your arm.
Stay Calm: Arrive early to avoid rushing and feeling stressed. A brief period of rest (10-15 minutes) in the waiting room can help your body settle down before the blood draw.
Listen to Your Body: If you feel unwell or have a fever, it may be best to reschedule, as illness can also impact hormone levels. Consult your doctor.

Conclusion

Preparing correctly for a testosterone blood test is crucial for obtaining accurate and meaningful results. By adhering to a few simple guidelines, you can eliminate external factors that could influence your hormone levels. The key takeaways are to schedule your test for the morning, avoid intense exercise and alcohol in the day or two prior, and communicate all medications with your healthcare provider. A good night's sleep and stress management are also vital. Following these steps ensures your doctor can make the most informed decisions about your health based on reliable data.

Additional Considerations for Repeat Testing

If your initial test results are abnormal, your doctor will likely recommend a repeat test to confirm the findings. Given that testosterone levels can vary from day to day, a single low reading might not indicate a chronic issue. For subsequent tests, it is especially important to maintain consistency in your preparation (e.g., test at the same time of day) to enable an accurate comparison of results. A comprehensive evaluation, including other hormone tests like luteinizing hormone (LH) and estradiol (E2), may also be ordered to provide a complete picture of your endocrine health.

What Not To Do Before a Testosterone Blood Test Checklist

Do not work out intensely for 24-48 hours before the test.
Do not consume alcohol for at least 24 hours prior.
Do not test in the afternoon if you are under 45 years old.
Do not start new supplements or stop prescribed medications without consulting your doctor.
Do not get less than 7 hours of sleep the night before.
Do not fast longer than your doctor advises or unless instructed to.
Do not get tested while you are ill.

By carefully following these instructions, you maximize your chances of getting a test result that accurately reflects your hormonal health.

For more in-depth information about the testosterone test and what it measures, you can consult reliable sources like MedlinePlus.

Frequently Asked Questions

Yes, intense exercise, particularly heavy weightlifting or endurance training, can temporarily fluctuate your testosterone levels. You should avoid strenuous exercise for at least 24 to 48 hours before your test to ensure an accurate reading.

You should not drink alcohol for at least 24 hours before your blood test. Alcohol can negatively affect hormone levels and other blood markers, leading to skewed test results.

The ideal time for a testosterone test is typically between 7 a.m. and 10 a.m., when testosterone levels are at their highest and most stable for the day. For men over 45, the time fluctuation may be less significant, but morning is still often preferred.

While not always required for testosterone specifically, fasting for 8 to 12 hours is often recommended if your doctor is ordering a broader blood panel. Always follow your healthcare provider's specific instructions regarding fasting.

Many medications, including opioids, corticosteroids, and certain antidepressants and statins, can affect your testosterone levels. You must inform your doctor about all drugs and supplements you are taking. Do not stop any medication without their approval.

Yes, insufficient sleep can cause a drop in testosterone levels. Since testosterone is produced during sleep, getting 7 to 9 hours of quality rest the night before your test is recommended for a more accurate result.

While some sources suggest a brief, temporary increase in testosterone right after ejaculation, studies show no significant long-term effect on blood testosterone levels. Abstaining for a day might be considered for maximum caution, but it's not typically required.