How to Prepare for a Testosterone Blood Test: Do's and Don'ts

Testing your testosterone levels is an important step in identifying hormonal imbalances and understanding your overall health—but getting accurate results depends on proper preparation. Testosterone levels fluctuate throughout the day and can be influenced by factors like food, stress, sleep, and medications. Without proper preparation, you may receive misleading results, which could lead to an incorrect diagnosis or unnecessary treatment.

In this guide, we’ll walk through how to prepare for a testosterone blood test, including the best time to test, fasting considerations, medications that may interfere, and lifestyle factors that can impact your results—so you can feel confident your results are as accurate and reliable as possible.

Testosterone levels follow a circadian rhythm, meaning they are highest in the morning and decline throughout the day [1].

Harvard Health says that the best time to test for total testosterone is between 7:00 and 10:00 in the morning. This timing applies to men under the age of 45. However, since testosterone levels fluctuate less with age, men 45 and older can have their testosterone test done any time before 2:00 in the afternoon [2,3].

Research has not found significant differences between fasting and non-fasting testosterone levels.[4] In some cases, your healthcare provider may ask you not to eat or drink anything except water several hours before the test, but your provider should let you know if you need to follow any specific instructions for your test.[5]

Best Practice: If fasting is recommended, schedule your test early in the morning before breakfast.

Some medications and supplements can artificially raise or lower testosterone levels. If you're taking any of the following, inform your healthcare provider before testing:

Medications that may lower testosterone levels [6]:

• Ketoconazole (Extina, Nizoral, Ketoderm)
• Cimetidine (Tagamet)
• Spironolactone (Aldactone)
• Certain antidepressants
• Chemotherapy drugs
• Opioids (morphine, codeine, hydrocodone, and oxycodone)
• Statins (cholesterol-lowering drugs)
• Corticosteroids [7]

Medications that may increase testosterone [8,9]:

• Testosterone replacement therapy (TRT)
• Anabolic steroids (manufactured forms of testosterone)
• Certain supplements (DHEA, zinc, quercetin, grape seed extract)

Tip: Review the supplements you are taking with your healthcare provider to decide if you should refrain from taking them before testing.

Aim for at least 7-9 hours of quality sleep the night before your test and avoid alcohol and caffeine before bed, as they can disrupt sleep cycles.

Testosterone production occurs at night while you are sleeping after it reaches its lowest around 7 p.m.[1] Research found that decreased sleep caused a drop in testosterone levels, especially in the afternoon and evening.[10] So, your test results can be affected by your sleep.

Chronic stress raises cortisol levels, which inhibits testosterone production. Engage in stress-reducing activities (meditation, deep breathing, light exercise) the night before.[11]

Why? Strenuous exercise, especially heavy weightlifting or endurance training, can cause temporary fluctuations in testosterone levels. Avoid intense workouts the morning of the test, as excessive exercise can temporarily lower testosterone levels. Light activities like walking or yoga should be fine.[12]

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, which can indirectly affect testosterone levels.

A testosterone test is often done alongside other hormone tests to provide a more complete picture of hormonal health:

• Free vs. Total Testosterone: Measures both bound and unbound testosterone
• Sex Hormone-Binding Globulin (SHBG): Helps assess how much testosterone is available for use
• Luteinizing Hormone (LH): Helps determine if low testosterone is related to a pituitary issue
• DHT (Dihydrotestosterone): A more potent androgen derived from testosterone
• Estradiol (E2): Elevated levels in men may indicate hormonal imbalance

Tip: Ask your healthcare provider if a comprehensive hormone panel is appropriate for you.

Testosterone Test Preparation Checklist:

• Test between 7–10 AM for the most accurate results
• Fast for 8–12 hours if required by your healthcare provider
• Inform your healthcare provider 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 (avoid sugary or caffeinated drinks)

By following these steps, you can help ensure your testosterone blood test provides accurate results and supports better-informed decisions about your health.

If you’re unable to visit a lab or prefer a more convenient option, you can also test your testosterone levels from the comfort of home. Everlywell offers an at-home testosterone test that makes it easy to collect a sample, send it to a certified lab, and receive clear, physician-reviewed results—helping you better understand your hormone health and take the next steps with confidence.