Distinguish a physiological decline and non-specific symptoms from genuine, diagnosed and confirmed hypogonadism.
In men, the hormonal assessment includes evaluation of androgen status and the search for possible causes of testosterone deficiency. A low testosterone must be interpreted in its clinical context and, when necessary, confirmed before any therapeutic decision.
These changes are common and often blamed on “age”. Sometimes they reflect an imbalance worth assessing, without drama.
The presence of symptoms is not a diagnosis of deficiency: they can have many other causes.
A rigorous, step-by-step pathway.
Symptoms and signs
Clinical evaluation
Morning testosterone (fasting)
Confirmation if low (≥2 measurements)
LH / FSH
Type of hypogonadism
Search for the cause
Assessment of contraindications
Shared decision
Low testosterone + high LH/FSH
Points to primary hypogonadism (testicular origin).
Low testosterone + low or inappropriately normal LH/FSH
Possible hypothalamic-pituitary origin; further investigations may be needed.
The problem lies in the testes; LH/FSH are usually elevated.
The problem lies in the hypothalamic-pituitary axis; LH/FSH low or inappropriately normal.
The diagnosis of testosterone deficiency must not rest on fatigue, low libido, age, reduced sports performance or a single testosterone measurement alone. It must combine compatible symptoms and a genuinely low testosterone level, measured in the morning under good conditions, confirmed on at least two occasions, together with a search for the cause.
Planning to have children? This must be discussed before starting TRT. Exogenous testosterone can markedly reduce intratesticular testosterone production, suppress or reduce spermatogenesis and reduce fertility. A fertility plan therefore changes the therapeutic approach.
Follow-up covers haematocrit and haemoglobin (risk of erythrocytosis), prostate monitoring and PSA according to age and risk, urinary symptoms, obstructive sleep apnoea, individual cardiovascular risk, fertility and possible effects such as gynaecomastia.
More testosterone does not mean a better outcome. The goal is to restore an appropriate physiological level when a genuine, diagnosed deficiency exists.
In men with correctly diagnosed hypogonadism, the literature documents, depending on the patient: improved sexual function and libido, increased lean mass, correction of certain anemias associated with the deficiency, improved bone mineral density and body composition, and some aspects of wellbeing.
What testosterone is NOT
It is not an anti-aging treatment, nor a universal cure for fatigue, nor a means of bodybuilding or weight loss, nor a systematic treatment after age 40, 50 or 60.
It is the combination of compatible symptoms and a genuinely low, confirmed testosterone (hypogonadism), not a mere age-related decline.
With compatible symptoms and a low morning measurement, confirmed on at least two occasions and interpreted in context.
In the morning and fasting, when testosterone is at its most representative level.
Because testosterone fluctuates; a single low value is not enough and must be confirmed.
Total is usually assessed; free can help in borderline cases or when SHBG is altered.
SHBG carries testosterone; if high or low, it changes how total testosterone is interpreted.
They help locate the origin: high points to a testicular problem; low or normal, to a central one.
Low libido, fewer morning erections, fatigue, muscle loss or low mood, among others; they are not specific.
In men with confirmed hypogonadism it can improve libido and sexual function in some cases.
It can increase lean mass in diagnosed deficiency, but it is not a bodybuilding aid.
It is not a weight-loss treatment; it may change body composition in genuine deficiency.
Yes; exogenous testosterone can reduce spermatogenesis and fertility. Discuss any fatherhood plans before treatment.
It can raise hematocrit and hemoglobin, which is why it is monitored during treatment.
It requires appropriate prostate monitoring according to age and individual risk.
Yes, PSA is monitored according to age and risk profile, before and during treatment.
Obstructive sleep apnea should be assessed and taken into account, as it may influence the decision and follow-up.
It depends on the case; it is usually maintained while the indication persists and the benefit–risk balance remains favourable.
Periodic clinical and biological checks (testosterone, hematocrit, prostate/PSA as appropriate) to adjust and monitor safety.
No; the goal is to restore an appropriate physiological level, not to exceed it.
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Each key clinical statement is grounded in reference recommendations. Last checked: June 2026.
Scientific review: Doctor Florian A. Vallecillo Cabrera · Metabolic medicine — Last reviewed: 2026-06
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