I'm already on TRT. Is it too late to get a baseline?

You can't recover the baseline you didn't take. But a current panel still earns its keep — it confirms suppression, tracks SHBG and Estradiol drift, and gives you the comparison point for any future pause or pivot.

Can I keep fertility on TRT?

Sometimes. Adjuncts like hCG or low-dose hMG can keep some intratesticular testosterone and partial spermatogenesis. It works for some men and not others. The panel tells you whether the adjunct is doing its job — without measurement, it's hope.

How long after stopping should I retest?

FSH and LH typically start moving within 4–8 weeks of stopping. Total testosterone follows. Three to six months is the realistic window to read recovery. A semen analysis is a separate test, ideally three months after the hormonal axis comes back.

Should I freeze sperm before TRT?

If kids are anywhere on your roadmap, the answer is yes. Cryopreservation before TRT is the only fully reversible safety net. Costs are typically modest compared to fertility treatment later. We're building a sperm cryopreservation product for late 2026; ESHRE-aligned partner clinics handle it today.

◆ TRT & Fertility

Before your first shot, know what you're working with.

TRT works by replacing the testosterone signal your brain would normally produce — which means LH and FSH drop to near zero within 4–8 weeks and sperm production follows. A six-marker hormone panel (Total + Free Testosterone, FSH, LH, SHBG, Prolactin, Estradiol) is the single test that documents your axis before TRT, confirms suppression during, and tracks recovery if you ever stop.

Exogenous testosterone shuts down the signal from your brain to your testes. LH falls to near zero within weeks, and sperm production follows. Most men only learn this when they want kids and find out it's complicated. A baseline panel is the simplest insurance you have.

Order the panel →Take the 2-min quiz

ISO-certified German lab · physician-reviewed · 3–5 days

≤ 1%

of TRT users have measurable sperm output after 12 months at full dose

~6 mo

median time for sperm production to recover after stopping (range: 3–24 mo)

30–50%

of men do not return to pre-TRT baseline once stopped

What TRT actually does

Three risks worth understanding before you start.

HPTA suppression is the point

TRT works by replacing what the brain would normally signal for. The hypothalamic-pituitary-testicular axis goes quiet — LH and FSH drop to near zero. That's not a side effect; it's the mechanism.

Spermatogenesis stops in weeks

Without LH and FSH, the testes stop producing sperm. Most men become functionally azoospermic within 10–24 weeks. Testicle size visibly decreases. Fertility on TRT is the exception, not the rule.

Recovery is a lottery

Stopping TRT doesn't guarantee a return to baseline. Roughly half of long-term users see partial-only recovery. The longer the cycle and the higher the dose, the worse the odds.

What to measure, when

Three windows where the panel earns its keep.

TRT is not a one-time decision — it's a sequence. Each window has a different question to answer, and the same six markers answer all three.

Before

Establish your real baseline

Most men start TRT on the back of a single low-T result from a GP. That is not a baseline — it's a snapshot. Two morning samples, fasted, before 10 am, gives you the number TRT is supposed to improve. Without it, you can never tell whether TRT is treating a problem or hiding one.

Total + Free Testosterone
FSH
LH
SHBG
Prolactin
Estradiol

During

Track the trade-off you accepted

On TRT, FSH and LH drop to near zero — that confirms the axis is suppressed. SHBG and Estradiol drift with dose. Tracking once or twice a year catches the slow drift before it becomes a symptom (low libido, gynaecomastia, water retention).

Total + Free Testosterone
SHBG
Estradiol
Prolactin

After / Pause

Confirm recovery — or its limits

If you ever want kids, you'll likely come off. Recovery is monitored by watching FSH and LH return, then total T, then sperm parameters (separate test). The same panel three months apart shows whether the axis is restarting or stuck.

FSH
LH
Total + Free Testosterone
Estradiol

Hormone Panel 01

Six markers, one finger-prick, German lab.

The same panel is used across all three TRT windows. Sample at home in the morning, drop in the post, results land in your dashboard with physician notes within 3–5 working days.

Total + Free Testosterone — the headline number, in clinical context
FSH and LH — the only markers that prove HPTA suppression or recovery
SHBG — decides how much of your testosterone is bioavailable
Estradiol — drifts with dose, missed by most GP panels
Prolactin — screens for the reversible pituitary cause of low T
Physician review — every panel reviewed before it reaches you

FAQ

What men on or planning TRT ask us.

Take the action that matters

Get your hormones measured before the window closes.

Order the panel today, sample tomorrow morning, results in 3–5 days. €89, ISO-certified German lab, physician review. The data is yours — keep it for the rest of your life.

Order the panel →Take the 2-min quiz first

FutureKit is not a TRT prescriber and does not provide medical advice. The Hormone Panel 01 is an in-vitro diagnostic test for screening and information. Decisions about starting, adjusting, or stopping testosterone replacement therapy belong with a qualified physician.