Blood-test timing planner
A trough blood test is drawn just before your next injection; a midpoint test is drawn halfway between two injections. Enter when you last injected and how often, and see the exact dates for your next three cycles, ideally as a morning draw.
This is an educational estimate, not medical advice. It doesn’t recommend a dose. Real levels vary a lot between people; only a blood test shows yours. Talk to your prescriber before changing anything. Your prescriber decides which timing they want. Use the same timing every time so results compare.
Enter your last injection
A morning draw (7–10 am) keeps results comparable. Have the blood taken before you inject.
TRTracker reminds you before your next draw and marks it on your level curve.
It keeps your injections and lab results together, so every result has its timing. Free on iPhone.
How it works
After an injection your testosterone rises for a day or two, then falls until the next one. So one blood test can read very differently depending on when it is taken. That is why your prescriber asks for a specific timing.
Trough means the lowest point, just before the next injection. The planner puts it on the morning of your injection day, before you inject, as long as that morning falls within the 24 hours before the shot. With daily injections it is simply just before your next one.
Midpoint means halfway between two injections. For testosterone cypionate and enanthate the Endocrine Society guideline suggests measuring here. The planner shows the exact halfway moment and the nearest morning.
Morning draws. Guidelines ask for morning samples when diagnosing low testosterone because levels follow a daily rhythm. On injections the timing relative to your shot matters more, but many prescribers still ask for mornings so every result is taken the same way.
The dates assume you inject on schedule. If you move an injection, enter the new date.
Sources
- Bhasin S et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab, 2018
- Mulhall JP et al. Evaluation and management of testosterone deficiency: AUA guideline. J Urol, 2018
- Depo-Testosterone (testosterone cypionate) prescribing information, DailyMed
Questions
Should my blood test be at trough or midpoint?
It depends on what your prescriber wants to know. A trough draw, just before the next injection, shows how low your level gets. A midpoint draw, halfway between injections, sits closer to your average; the Endocrine Society guideline suggests it for testosterone cypionate and enanthate. Ask which one they want, and use the same timing every time.
Do I inject before or after a trough blood test?
After. A trough is the lowest point before the next dose, so have the blood drawn first and inject afterwards, the same day.
Why a morning draw?
Testosterone follows a daily rhythm and guidelines ask for morning samples when diagnosing low testosterone. On injections the timing relative to your shot matters most, but many prescribers still ask for a morning draw so results compare from test to test.
How soon after starting or changing a dose should I test?
Levels take several weeks to settle after a change (about five half-lives). The Endocrine Society guideline suggests checking 3 to 6 months after starting, then yearly once stable; your prescriber may test sooner.
Is anything I type saved?
No. The dates are worked out in your browser and nothing is stored. The calendar file and the PDF are made on your device. If you ask us to email it, we send it once and keep no copy of it or your address.
More free tools
- Low-T symptom self-checkEleven quick questions about symptoms that can go with low testosterone, and what to ask your clinician.
- Testosterone level calculatorSee the shape of your levels between injections: peak, trough and how long until they settle.
- Injection volume calculatorTurn your prescribed mg dose into mL and insulin-syringe units, with the syringe drawn to the line.
- Injection site rotation plannerPick your approved sites and schedule, and see where your next 8 injections go on a body map.
- Injection schedule plannerLay out 12 weeks of injection dates, with the trough blood-test window before each one.
- Free testosterone calculatorEstimate free and bioavailable testosterone from total T, SHBG and albumin (Vermeulen).
- Vial supply calculatorSee how many injections a vial holds and when you will need a refill.
- All toolsEvery free calculator, including the ones on the way.
Your real curve, in your pocket
Log each injection and lab result. TRTracker redraws the curve for you, with the uncertainty range.
Download on the App Store
Scan with your iPhone
Free tools for education only. Nothing you type here is stored; the maths runs in your browser, and your result is only sent if you ask us to email it. TRTracker does not provide medical advice, diagnosis or treatment. Privacy policy