Most people know that chemotherapy can cause hair loss, fatigue, and nausea. But the phenomenon of “chemo brain” is less well-known, even though many cancer patients struggle with it. Forgetfulness and difficulty concentrating are common after cancer treatments. But what exactly is chemo brain, and what can you do about it?

Forgetful after chemo: sound familiar?

Starting a sentence and forgetting halfway through what you wanted to say, keeping endless lists so you don’t forget things, struggling to focus on a crossword puzzle, getting easily distracted at work… These are just a few examples of the forgetfulness and mental fuzziness that can occur after chemotherapy and other cancer treatments like radiotherapy, hormone therapy, or surgery.

Chemo brain in a nutshell

Chemo brain is best described as a loss of mental sharpness. You may find it difficult to multitask, struggle to learn new skills, or search for words, names, or dates that used to come easily. Everything feels slower, and it can seem almost impossible to keep your focus.

Causes and effects of concentration problems after chemo

The exact cause of chemo brain isn’t fully understood. It can occur at any point during your cancer journey. Besides treatment itself, other factors may play a role, such as age, menopause, medication, or lack of sleep.

The good news is that for most cancer patients, the problem is temporary. However, the effects can still be very disruptive to your work, studies, and social life. To others, nothing seems visibly wrong, but for you, everything feels different. Your brain just doesn’t function the way it used to, and that’s incredibly frustrating. For some, the issue lasts longer and has a bigger long-term impact.

It's okay if you're not (always) a superwoman

What can you do about it?

Don’t stress yourself out or obsessively train your brain with memory games and exercises. That will only leave you more frustrated. Instead, slow down, clear your mind, and plan for more rest.

Make sure you get enough sleep, eat plenty of vegetables—great for brain health—and avoid alcohol or anything that disrupts your sleep cycle. Meditation can also help by improving focus and awareness.

And don’t be afraid to ask family and friends for help with everyday tasks. Talking about the issue will not only make you feel better but also help others understand what you’re going through. Unlike hair loss, chemo brain isn’t visible, and because it’s less known, it can lead to misunderstandings. The more openly you communicate about it, the easier it will be for colleagues, friends, and family to support you.

Extra tip: keep a journal!

Track when you experience memory problems. You might notice patterns, like connections to certain medications, times of day, or specific situations. This helps you anticipate problems or avoid challenging situations altogether. Your journal is also a valuable tool when discussing the issue with your doctor since you’ll have concrete examples to share.

Struggling with chemo brain? Six practical tips to make daily life easier:

1. Use a detailed planner, notebook, or smartphone to keep track of all your appointments, to-do lists, birthdays, notes, interesting websites, books, and more—in one place.
2. Figure out when your energy levels are highest during the day—your journal can help with this!—and schedule the most mentally demanding tasks for that time.
3. Routine helps! A steady daily structure makes it easier to stay focused.
4. Always keep your keys, wallet, handbag, and other easy-to-lose items in the same place—like a basket in the hallway.
5. Don’t multitask. Studies show that multitasking doesn’t work for anyone, especially when you’re struggling with concentration after chemotherapy.
6. Add a splash of humor to your forgetfulness. Laughter really helps. Plus, chemo brain can be a convenient excuse when you’ve forgotten a friend’s birthday… again ;-)