Aromatase Inhibitors

Anastrozole, letrozole and exemestane: what they are

Three molecules make up this category. Anastrozole is stocked at 1MG, letrozole at 2.5MG and exemestane at 25MG. All three reduce the amount of oestrogen the body produces by blocking the aromatase enzyme, which converts androgens into oestrogens. Anastrozole and letrozole are non-steroidal and reversible; exemestane is steroidal and binds irreversibly, which is why it is sometimes used after one of the others.

Licensed use and off-label use

Their principal licensed use is in hormone-receptor-positive breast cancer in postmenopausal women, typically taken daily over several years. Letrozole has a second established use in ovulation induction, given as a short course early in the cycle. Beyond those, these molecules are used by some people to manage oestrogen while taking anabolic compounds, which is outside what they were approved for.

What lowering oestrogen actually does

The effects of substantially lowering oestrogen are the thing to understand. Bone density falls over time, which is why bone monitoring is part of proper long-term treatment and why calcium and vitamin D are often added. Joint pain and stiffness are common and are the most frequent reason people stop. Cholesterol can shift unfavourably. Hot flushes, fatigue and mood changes are reported. Pushing oestrogen too low causes its own problems: joint discomfort, low libido, poor lipid profile and effects on bone. More suppression is not better.

Why blood work is not optional

None of that is assessable without blood work, and oestradiol is not a number to guess at. A doctor can order and interpret it.

Taking them consistently over years

All three are taken continuously rather than in courses when used in breast cancer, and consistency of timing helps with adherence over treatment measured in years. Missing the occasional dose is not an emergency, but doubling up the next day to compensate is not the answer either.

Sourcing, expiry dates and delivery

Each product page lists the molecule, the strength and the pack size, with the guaranteed minimum expiry date shown before you add it to the basket. Use the active ingredient filter to see every brand of a given molecule together. All stock ships from India through licensed distributors.