Any ideas on what is the cause of my sudden hair loss, severe thinnin

Anastrozole has caused my hair to greatly thin. I have been on it a year. With all the side effects out there that can happen, I can deal with this. Granted I am not very happy about it all. If it gets that bad, I guess I will go short or wig it. I don't have any other side effects with the exception if I eat certain foods, that are bad for you anyway, or occasionally drink, I have the hot flashes, joint pain, swelling, stiffness. So, I try to eat healthy. I am going to try Nutrafol as well to see if it helps. I am not going to take another drug for hair loss. 53yo, 1 yr after surgery, ILC, ILCIS, hyperplasia, Stage 1, no lymph node involvement. The ILC was only 2mm when they found it on my very first MRI scan for dense breasts. I feel very lucky as some of my friends have not been very recently.

@girlsfly check with your doctor before you start Nutrafol. My dermatologist said it works but he wouldn’t recommend it without permission from oncologist because it contains plant sterols. Found out Nutrafol does stimulate estrogen so it was not recommended if HR+ and on meds.

@briarrose My oncologist is doing regular testing for tumor markers by doing a blood test. I had a mastectomy in Feb 2025 and he just checked for my first tumor marker blood test in late September. Haven't gotten the result yet, but apparently there's a normal range of substances in the blood and when they are detected as high, the results indicate a progression of cancer in the body and can guide treatment decisions such as sending patient on for scans. It's one way of monitoring and detecting a recurrence.

Thank you brightlight66.
Unfortunately my breast oncologist said the ACS doesn't recommend blood tumor markers in early stage BC.
And her facility complies with such policy. Hopefully my new breast oncologist and cancer care center will do the tumor markers. Just because I had early stage BC (with one positive lymph node) does not mean I am in the clear!
She talked about "false positives"...and offered me no answer when I questioned "how will I know if the cancer comes back?"
Shouldn't a breast cancer medicine oncologist have an answer to this question we all ask?
I don't understand it. Thank you again for letting me know there ARE oncologists out there that DO the cancer markers...because, again, how will I know if it reoccurrence?
Sending all lots of positive energy as we travel this journey no one wants to be on.

@briarrose my oncologist has been doing tumor markers from the start. Have read a lot about them (there are many) and that some doctors won’t use them because don’t feel they’re accurate. Mine went down after surgery, chemo, radiation but never to normal range. Then it suddenly started to go back up about 3 months into ai therapy till within 3 points of where we started. At that point he ordered pet scan and brain imaging (luckily both negative). It has dropped back down and has now been stable (but still not normal) for about 10 months. So will continue to monitor but to me, it means I stay on ai therapy because no one knows why some of us may never go “normal”. He’s still monitoring every 3-6 months.

Thank you kindly mistymar for your information.
You gave me issues to address when I see my new oncologist late October.
The appointment can't get here soon enough.
Be well.

Hi! @briarrose:

I am so sorry to learn that your medical oncologist would not perform cancer markers checking for their patients with early stage BC. However, you may express your concern for the recurrence/metastasis issue of BC with your primary care physician, for early detection is the key to treat any cancers. My PCP sets up quarterly blood work for me to check various tumor markers and carcinoembryonic antigens in my blood, such as: CA 15-3, CA 19-9, etc., based on my overall health concern. Due to the fact that I declined the radiation treatment for fear of its potential long term effect at my old age, I dared not to ask my team of oncologists for any extra blood work. My PCP and I agree that we'll continue doing quarterly blood tests, so long as these tumor markers stay consistently low we'll have the peace of mind knowing that the aromatase inhibitors medication that I've been taking is doing its job. Should any of these tumor markers be elevated suddenly, we'll then bring it to the attention of my team of oncologists and ask for imaging scans such as: MRI or PET scan depending on which tumor markers appear to be in question.

Wishing everyone a better journey ahead with peace, health, and love!

Thank you lifetraveler!
Unfortunately I did discuss this with my PCP and she didn't feel comfortable ordering the cancer marker blood work. She felt it was oncology who should take on this responsibility.
So I am counting on my new breast oncologist - seeing her the end of October - to order the blood work.
Again, many thanks for sharing your particular situation. It all makes sense to me.
Wishing you all the best on your journey! Be well!

@girlsfly I didn't like Nutrafol as I didn't see one ounce of improvement after 90 days. Perhaps I'm on the side of the percent where it doesn't work. I am African American, and so many of the hair saving products tend to not work for us and our curly hair.

I used to have fairly thick, full hair but now it's all stringy, very thin and the whole thing from root to tips looks like dead/split ends. I have never been 100% sure if it's from verzenio, exemestane or lupron or all 3. I pretty much started on them all at the same time, so it was hard to know what came from what. My hair thinned out in clumps, starting after about 6 months of beginning all of the above and has never come back to anything more but I am still on all that same stuff. I have tried different supplements, shampoos, etc... I have yet to find anything that has helped. If yours was caused by the Anastrazole and it very well could have been, I am not sure how long it takes for everything to get back to normal hormone wise and then for hair to regrow can take a while after. Hair growth cycles and all that. Hopefully it will just take some more time.