Oestrogen and TRT: Should you be concerned about high oestrogen levels?

When you start testosterone replacement therapy (TRT), there’s a lot of focus on raising testosterone to a healthy level, but oestrogen matters too. 

In this blog, we’ll cover everything you need to know about oestrogen and TRT, including when high oestrogen might cause problems, how to manage it safely, and why aromatase inhibitors aren’t always the best solution.

Contents:

• What is oestradiol and why does it matter?
• Does TRT raise your oestrogen levels?
• What is considered a high oestrogen level on TRT?
• Signs your oestrogen level may be too high
• Do I need an oestrogen blocker on TRT?
• Ways to prevent or manage raised oestrogen on TRT
• Why some men feel fine even with high oestrogen levels
• Keeping oestrogen in balance

 

What is oestradiol and why does it matter?

Oestradiol is the most active form of oestrogen in the body, and although it’s often thought of as a female hormone, it plays essential roles for men too.

Healthy oestradiol levels in men help to:

• Protect bone density
• Support cardiovascular health
• Regulate mood and emotional wellbeing
• Maintain sexual function and libido

Too little oestradiol can cause just as many problems as too much, including joint pain, depression, poor libido, and even an increased risk of fractures.

Maintaining a good balance of testosterone and oestradiol, rather than aiming to eliminate oestrogen, is crucial for long-term health.

 

Does TRT raise your oestrogen levels?

Yes, it often does, and that’s completely normal. In fact, around a fifth of men on TRT have raised oestrogen [1].

When you’re on TRT, your body naturally converts some of that extra testosterone into a form of oestrogen called oestradiol.

This process happens through an enzyme called aromatase, which is found mainly in fat tissue, the liver, and other parts of the body.

This means that raising testosterone with TRT usually increases oestradiol levels too. In many cases, that’s exactly what you want: a healthy ratio between testosterone and oestrogen is important for your physical and mental well-being.

 

What is considered a high oestrogen level on TRT?

It’s important to distinguish between total oestrogen and oestradiol levels. The two are quite different. We tend to measure oestradiol levels when monitoring TRT.

Normal male oestradiol levels are usually around 40–150 pmol/L, depending on the laboratory.

On TRT, levels often rise to the 100–200 pmol/L range without causing issues.

Levels consistently above 200–250 pmol/L, especially alongside symptoms, may warrant closer monitoring and careful management.

 

Signs your oestrogen level may be too high

If your oestrogen levels rise too much on TRT, they can start to cause symptoms. The point at which this happens varies, just as healthy baseline levels look different from man to man.

Symptoms of raised oestrogen include:

• Water retention — this can lead to bloating, weight gain, or swollen ankles
• Mood changes and emotional sensitivity — you might find yourself feeling more tearful, irritable, or anxious
• Gynaecomastia — this refers to enlarged (and sometimes tender) breast tissue; itchy nipples are also a common sign
• Reduced libido or soft erections — high oestrogen can blunt sexual desire
• Acne — hormonal shifts can trigger breakouts, especially if you’re already prone to them
• Tiredness — if too much testosterone is converted to oestradiol, you may feel more tired than usual

 

Do I need an oestrogen blocker on TRT?

In most cases, no.

While TRT can raise your oestradiol level, that doesn’t mean you automatically need medication to lower it. What matters most is whether your oestrogen is causing symptoms that affect your quality of life and whether your blood tests support a clinical need to intervene.

Even if your oestradiol is above the normal reference range, if you feel well, there’s often no need to act. At Leger, our doctors can help you interpret your results and decide what (if anything) needs adjusting. Book a consultation here.

In rare cases, some men may benefit from a medication called an aromatase inhibitor (AI), which blocks the conversion of testosterone into oestrogen. But AIs come with important risks and should only be used under expert supervision.

Potential side effects of aromatase inhibitors include:

• Bone loss – oestrogen is essential for bone strength
• Mood changes – very low oestrogen can increase anxiety or depression
• Cardiovascular impact – overly suppressing oestrogen may raise heart risk

Because of these risks, AIs should only be used when absolutely necessary — and only as part of a personalised, medically supervised treatment plan.

 

Ways to prevent or manage raised oestrogen on TRT

If oestradiol starts creeping too high, there are several ways to manage it, and medication is usually the last resort.

You can lower oestrogen by:

• Lowering your testosterone dose: Using more testosterone than needed can increase aromatisation.
• Adjusting your injection frequency: Smaller, more frequent doses can help reduce peaks that trigger oestrogen conversion.
• Losing weight if you’re overweight: More fat tissue means more aromatase activity, leading to higher oestradiol production.
• Minimising alcohol intake: Alcohol can raise oestrogen levels and disrupt hormone balance.

Our team can help you assess whether a simple tweak, like adjusting your dose, might be enough to improve your oestrogen balance naturally.

 

Why some men feel fine even with high oestrogen levels

Oestradiol reference ranges are designed for men who are not on TRT. When you're on TRT, it’s normal for oestrogen levels to run slightly higher than standard lab ranges.

What matters most is how you feel.

If you have a higher oestradiol reading but no side effects — good mood, strong libido, no water retention — then lowering your oestrogen could do more harm than good.

 

Keeping oestrogen in balance

A rise in oestrogen on TRT is normal. In most cases, no treatment is needed unless symptoms appear.

With regular blood monitoring, personalised dose adjustments, and expert support, you can keep your hormones balanced and feel your best.

If you're concerned about your oestrogen levels or need help managing your TRT journey, get in touch with our team. We'll get you back to feeling your best.

 

References

1. Tan RS, Cook KR, Reilly WG. High estrogen in men after injectable testosterone therapy: the low T experience. Am J Mens Health. 2015;9: 229–234. doi:10.1177/1557988314539000
2. Butaney M, Thirumavalavan N, Balasubramanian A, McBride JA, Gondokusumo J, Pastuszak AW, et al. Treatment of estrogen levels in the management of hypogonadism: An anonymous survey of ISSM members. Urology. 2020;139: 104–109. doi:10.1016/j.urology.2020.01.032