Exemestane myths: 'it is a steroid' and other confusions

Exemestane is an aromatase inhibitor tablet used for hormone receptor positive breast cancer, mainly in women who have been through menopause. It is often described as a steroidal aromatase inhibitor, and that word causes a lot of worry. People hear steroid and think of prednisolone or dexamethasone, which can raise blood sugar, cause weight gain and weaken the immune system, or of the muscle-building steroids misused in sport. Exemestane is neither of these. The word steroidal simply describes its chemical shape, which resembles androstenedione, the natural hormone that the aromatase enzyme normally turns into oestrogen. Because it looks so similar, exemestane fits into the enzyme and switches it off permanently, so the body makes much less oestrogen. Letrozole and anastrozole, the non-steroidal aromatase inhibitors, block the same enzyme in a reversible way. Exemestane does not act like a cortisone medicine, and it does not build muscle. A breakdown product has weak male-hormone-like activity, which may explain why a few women notice mild effects such as oily skin, acne or slight hair thinning. Other common confusions include thinking exemestane is chemotherapy, that side effects prove it is working, that switching tablets means the first one failed, or that it is weaker than other aromatase inhibitors. None of these is true.

Steroidal describes shape, not action

Exemestane is shaped like a natural hormone so it can lock onto the aromatase enzyme.

It is not a cortisone-type steroid

It does not have the effects on blood sugar and immunity linked to prednisolone or dexamethasone.

It is a hormone therapy

It works by lowering oestrogen, not by killing dividing cells like chemotherapy.

Clearing up myths does not mean exemestane is free of problems. Some concerns are reasonable.

Side effects are real

Joint pain, stiffness, hot flushes, tiredness and low mood are common with all aromatase inhibitors, including exemestane. They deserve attention rather than dismissal.

Bones still need care

Although its structure has led to suggestions of gentler effects on bone, exemestane can still thin the bones. Bone density checks and calcium, vitamin D and exercise remain important.

Cholesterol can change

Aromatase inhibitors can affect cholesterol levels, so routine checks are sensible, especially if you have heart risk factors.

What this page cannot tell you

It cannot tell you which aromatase inhibitor is best for you. Your oncologist can weigh your health and preferences.

A few simple questions help separate useful advice from worry.

Who is saying it?

Cancer charities, national health services and your own team are more reliable than social media posts or product sellers.

Is it about the same medicine and situation?

Advice about steroids, fertility tablets or a different cancer may not apply to you.

Bring it to your appointment

Write down anything that worries you and ask your oncologist or pharmacist. No question is too small.