Why testing comes first
Testosterone replacement therapy (TRT) is a long-term treatment that affects several body systems. Starting safely involves three steps: confirming genuine deficiency, checking for contraindications or cautions, and discussing fertility clearly.[1]
Many men assume a “hormone package” showing a low number is enough. A laboratory package cannot replace clinical assessment; numbers must always be read alongside symptoms, history and examination.[1]
What baseline checks achieve
Baseline testing does two things. It identifies limitations or risks that mean testosterone should not be used, or should be used with care. And it provides a starting point for comparison, so later changes can be attributed correctly to treatment or recognised as pre-existing.[1]
Agreeing a follow-up plan from the outset also makes treatment safe and effective, rather than continuing injections without knowing whether the blood is thickening or blood pressure is rising.
A low result does not mean everyone needs TRT
Estimates of testosterone deficiency vary widely with age, illness and diagnostic criteria, and the proportion with a low result is not the proportion who should receive TRT.[1] Many men with mildly low levels improve with weight loss, better sleep and treatment of related conditions.
How external testosterone affects the body
Understanding its effects explains why each check matters.[1],[2]
- It stimulates red blood cell production, raising haematocrit. If it rises too far, the blood thickens and clot risk increases.
- It suppresses sperm production, because the brain senses enough testosterone and reduces the LH and FSH that drive the testes.
- It can raise blood pressure. The US FDA has updated the labelling of all testosterone products to state this.[3]
- The prostate responds to androgens, so monitoring is guided by age and risk.
Which checks are needed
Tests should be chosen for each person; not everyone needs everything. Typically they include[1],[2]:
- Confirming the diagnosis: fasting morning testosterone that is low on at least two occasions, with compatible symptoms.
- Finding the cause: LH and FSH, and in some cases prolactin or other pituitary tests.
- Blood count: haematocrit, which the Endocrine Society advises should prompt caution if above 50% before starting.
- Blood pressure: measured before starting and at every follow-up.[3]
- Prostate: risk assessment and PSA according to age and individual risk.
- Sleep apnoea: questions about snoring and daytime sleepiness, because untreated apnoea may worsen.
- Fertility plans: an honest discussion of whether, and when, you want children.
Agree the plan before starting
Before starting, agree what will be monitored and when: the symptoms you hope will improve, testosterone levels, blood pressure and haematocrit.[1],[2] Clear goals from the start make it possible to judge whether treatment is really helping, and when to stop.
If fertility matters, alternatives should be discussed first, because external testosterone suppresses sperm production. Your doctor may consider medicines that stimulate your own production instead.[1],[2]
How we care for you at Dr. Kris Clinic
We do not “test once and inject”. Everyone interested in TRT has a history and examination, confirmed morning blood tests and only the baseline checks that suit them. We then explain each result and what it means, in English or Thai.
If you decide to start, we write down a clear follow-up plan, including blood test timing, blood pressure checks and symptom review, to keep long-term treatment as safe as possible. If you are already on TRT from another provider, bring your records and we will review them with you.
Frequently asked questions
I had a hormone package done. Can I start injections now?
Not yet. The result needs confirming with a morning test, symptoms need assessing and baseline safety checks are needed first.
Why check haematocrit?
Testosterone stimulates red blood cell production. Blood that becomes too thick raises clot risk, and a baseline value lets changes be tracked properly.
I still want children. Can I use TRT?
It is not recommended while you are trying to conceive, because it suppresses sperm production. Your doctor can consider alternatives.
Does everyone need a PSA test?
It depends on age and individual risk. Your doctor will assess this and explain the benefits and limits of testing.
Baseline tests before TRT should be tailored to the individual, and a monitoring plan agreed before treatment begins.[1] The essentials are confirming the diagnosis, checking safety and discussing fertility.
Talk to a doctor about this
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Dr. Krida Uakridathikarn (Dr. Kris)
Board-certified family physician with certificate training in clinical sexology and sexual medicine. He works at Suratthani Hospital and provides sexual health, hormone and LGBTQ+ inclusive care at Dr. Kris Clinic. Profile and CV
References
- EAU Guidelines 2026: Male Hypogonadism
- Endocrine Society: Testosterone Therapy for Hypogonadism (2018)
- FDA: Testosterone Information; June 2026 labelling update
Keep reading
Main guide: Men's sexual health
Low Testosterone: Symptoms and How It Is Properly Diagnosed
Testosterone Injections or Gel: How They Differ and How to Choose
Testosterone Enanthate vs Undecanoate: How the Two Injections DifferThis article is general education, not personal medical advice or a promise of results. Diagnosis and treatment require assessment by a doctor. Content reflects the cited sources as of the update date.