A lot of men think oestrogen is something to eliminate. In reality, it’s essential — and the goal isn’t to block it, but rather to balance it.

Why oestrogen increases on TRT

When you take testosterone, some of it naturally converts into oestradiol (a form of oestrogen) through a process called aromatisation. This happens in fat tissue, the brain, and other parts of the body. It’s completely normal — and expected — for oestrogen to rise on TRT.

Why men need oestrogen

Despite its reputation as a “female hormone,” oestrogen plays a critical role in men’s health:

Mood & brain function: Oestrogen supports mood stability, memory, and cognitive sharpness.
Sex drive & erections: Low oestrogen can reduce libido and impair erections.
Bone strength: Without enough estradiol, bones weaken — leading to long-term risks like osteoporosis.
Fat distribution & metabolism: Blocking oestrogen leads to more body fat and metabolic issues, even when testosterone levels are high.

Side effects of oestrogen

Oestrogen only becomes a problem at the extremes:

Too high: Can cause water retention, breast tissue growth (gynecomastia), mood swings, or reduced sexual function.
Too low: May lead to joint pains, low libido, irritability, and fat gain — plus higher risk of fractures and heart issues over time.

Should you use an oestrogen blocker?

Some men are tempted to take aromatase inhibitors (AIs) like anastrozole. But these were designed for cancer treatment, not routine TRT use. Over-suppressing oestrogen can backfire — causing joint pain, fatigue, and emotional flatness4.

AIs can be considered when:

You develop painful or growing breast tissue
You have persistent mood swings or low libido
Your estradiol is significantly elevated with symptoms

In most cases, adjusting your testosterone dose or frequency can help bring oestrogen back into balance — without needing additional medication.

Final word: It’s about balance

Oestrogen isn’t your enemy — it's part of the hormonal balance your body needs to function properly. If you feel good on TRT, a slightly higher oestrogen level often isn’t a problem. Don’t chase numbers. Focus on how you feel — and work with your TRT doctor to find what’s right for you.