Free Testosterone Screen
Free Testosterone is generally regarded among physicians as best correlated to true androgenic state. What this means for TRT is that your Free Testosterone level and it's fluctuation (high and low) play a major role in how you feel.
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Your Total Testosterone levels, combined with SHBG and Albumin levels, control your Free T levels. By using the Free Testosterone Calculator with the Peak-Trough Fluctuation screen, our app helps you to dial in to any Free T levels you want.
The Free Testosterone levels that alleviate symptoms and get you feeling your best (dialed-in) are completely individual to you. Learning what range you feel best in — and staying within that range — is key to proper management and staying side-effect free on Testosterone Replacement Therapy.
Free Testosterone Tutorial
Free Testosterone
Out of the Total Testosterone in your body, Free Testosterone is the portion that is ready for use. The rest of your Total Testosterone is bound up by Albumin and SHBG (Sex Hormone Binding Globulin).
Albumin weakly binds up a portion of your Total Testosterone. One way to think of Albumin is like a checking account. When you are low on cash, you can quickly go to an ATM and withdraw more from your checking account. Similarly, your body can pull extra Free Testosterone from the portion bound to Albumin.
SHBG binds it's portion of Total Testosterone more intensely. You can think of this like a savings account. When you are low on cash and go to an ATM, the amount in your savings account is not readily available for withdrawal. First you must transfer from savings to checking in order to get cash out of the ATM. Likewise, for your body to access the Total Testosterone bound to SHBG, it requires an extra step, so it is not considered readily available (Bioavailable).
Our Free Testosterone Screen calculates Free Testosterone levels and is based off the Vermeulen Equation. It requires that you input your SHBG and Albumin levels from a recent blood test, as well as the Total Testosterone amount you would like to see results for. Comparable to the way Total Testosterone fluctuates — as seen on the Peak-Trough Screen — Free Testosterone also fluctuates because it's a percentage of your Total Testosterone. This is important to remember, as Free Testosterone's peak and trough will largely determine how you feel on a specific TRT protocol (medication schedule).
Total Testosterone
For the Total Testosterone box, you can enter the Total Testosterone value from your blood test results, or any Total Testosterone level you would like to see the calculated Free Testosterone for. For the Total Testosterone units, you have a choice of either ng/dL or nmol/L. Unit conversion can be easily found online, if necessary.
Albumin
For the Albumin box, enter the Albumin value found on your most recent blood test results. If you haven't had a blood test for Albumin, it can be estimated at 4.3 g/dL or 43 g/L.
SHBG
For the SHBG box, enter the SHBG value found on your most recent blood test results. The units are fixed to nmol/L.
Results: Graph & Numbers
The pie chart shows the percentages of Free Testosterone (Free T), SHBG-Bound Testosterone (SHBG-BD), and Albumin-Bound Testosterone (Alb-BD), out of the Total Testosterone amount you entered.
Above the pie chart you will find the values for SHBG-Bound T and Albumin-Bound T. These values are listed in the same units that you chose when you entered the Total Testosterone amount.
The Free Testosterone value is listed in the box below the pie chart, and is also in the same units that you chose when you entered the Total Testosterone amount.
If you would like to know your calculated Bioavailable Testosterone, simply add Free T and Albumin-Bound T.
Combining Peak-Trough & Free T Screens
By using the Free Testosterone screen with the data from the Peak-Trough screen, you can see how high Free Testosterone rises after an injection and how far it falls before the next injection. Understanding how these two screens work together, how important Free Testosterone fluctuation is, and reporting how you personally feel at different levels, should all lead to some excellent decision making with your doctor.
Free T Screen Conclusion
Key Takeaways:
1. Free Testosterone's peak and trough is highly responsible for how TRT makes you feel, and whether or not you become symptom free (dialed-in).
2. Free Testosterone fluctuates between injections, as it's the unbound portion of Total Testosterone which fluctuates.
3. Albumin and SHBG bind up the majority of Total Testosterone and limit how much is free in your body.
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4. The Peak-Trough Screen can be used with the Free Testosterone Screen to check calculated Free Testosterone levels on various medication schedules.
5. The Free Testosterone levels that alleviate symptoms and get you feeling your best (dialed-in) are completely individual for you.
