TRT works best when it restores testosterone to a normal physiological range — typically 15–25 nmol/L at trough. Going above that threshold doesn't improve the benefits, but it does introduce real risks. Here's what to watch for and what to do.
Signs Your Testosterone Is Too High
Elevated haematocrit
TRT stimulates red blood cell production. Haematocrit above 54% thickens the blood and raises clotting risk — the most serious safety concern.
High oestradiol
Excess testosterone aromatises to oestradiol. Signs include water retention, mood swings, sensitive nipples, and low libido — counterintuitively similar to low T.
Acne or oily skin
Testosterone stimulates sebaceous glands. Sudden acne on the back, chest, or face often signals a dose that's too high or an injection frequency mismatch.
Sleep apnoea worsening
TRT can worsen or unmask sleep apnoea by altering respiratory drive. Poor sleep, morning headaches, and excessive snoring are warning signs.
Irritability or aggression
Supraphysiological peaks — particularly in the days after injection — can cause mood instability that isn't present at stable therapeutic levels.
Testicular atrophy
Exogenous testosterone suppresses LH, which signals the testes to produce testosterone. Without LH, testicular volume decreases over time on TRT.
The Haematocrit Problem
Testosterone stimulates erythropoietin (EPO), which drives red blood cell production. This is beneficial when levels are therapeutic — but when haematocrit rises above 52–54%, the blood becomes significantly more viscous, raising the risk of deep vein thrombosis, pulmonary embolism, and stroke.
This is why haematocrit monitoring every 3–6 months is not optional — it's a core safety requirement of TRT management.
High Oestradiol on TRT
The enzyme aromatase converts testosterone to oestradiol, and this aromatisation increases with higher testosterone doses and with increased adipose tissue. High oestradiol is often mistaken for "low testosterone returning" because symptoms overlap — but checking blood levels makes the distinction clear.
If oestradiol is consistently above 200–250 pmol/L, your GP may adjust injection frequency (more frequent smaller doses reduce peak-driven aromatisation), recommend lifestyle changes, or in some cases prescribe an aromatase inhibitor.
What Your GP Will Do
- Confirm the elevation with a trough-timed blood test
- Reduce dose or extend injection interval — minor adjustments first
- Monitor haematocrit closely if it was approaching threshold
- Assess symptoms at follow-up 6 weeks after adjustment
- Consider referral to haematology if haematocrit remains elevated despite protocol changes
TRT Monitoring at Lambert Medical Practice
If you're concerned your TRT dose needs adjusting, we can review your bloods and protocol — in Surbiton, with same-week results.
Book a TRT Review TRT Clinic