Estrogen blockers: Is there anything that helps with brain fog?

I had brain fog on tamoxifen that was dose dependent. Having been on and off it a couple of times I can say it took my body about 3 months to fully adjust to the med with some side effects going away.
If you’re on and AI, I think you’ll hear from others that a change in the type of AI might help.

Thank you that gives me hope. Im also taking vitamin b complex. Which i think is helping too.

Whether true or not, I read that some of the B vitamins can be an estrogen enhancer? (I only take the B vitamins my blood results showed I was deficient in. For me it is B12 & Folic Acid.)
I had a lumpectomy and lymph node biopsy, then 5 weeks of radiation, refused chemo treatment. Breast cancer is E+,P+,Hers2-. Prior to surgery I had to ween off the bio identical hormones I’ve been taking for almost 20 years since a full hysterectomy for endometriosis.
I have been miserable since with hot flashes, insomnia, heart palpitations, anxiety, all joint aches, muscle weakness, headaches, belly bloat, constipation, & weight gain. Went to a Gynecologist after my Cardiologist ordered a full panel
Blood work up, which showed ANA Titer Positive which I was told may indicate I have Rheumatoid Arthritis. After some research, I found there could be a link between Autoimmune Diseases and Hormonal Imbalance. I asked to be referred to a Gynecologist first. I will go to. Rheumatologist eventually. . I have been taking Anastrozole half of 1 mg. Tab & bio identical testosterone .75 mg. Troche Daily for almost a month now. I am also taking Relizen by Bonafide 2 tabs a day, hormone free supplement an Oncologist at Moffitt Cancer Hospital recommended. So far, I am noticing the hot flashes are not as frequent, insomnia still there but am sleeping a little bit more than before. Yesterday, I had my 6 month follow up with my surgeon. When I told her why I was not taking Tamoxifen, and what I was taking, (stating the Anastrozole blocks the testosterone from converting into estrogen, since I can’t have estrogen or progesterone as my diagnosis is a hormone driven cancer), in its place, she said, “but don’t those 2 cancel each other out?” Well, I’m not a medical person, so I didn’t know. Only that if that is the case, why would my Gynecologist prescribe me these medications? I see her, my Gynecologist tomorrow. Am very anxious to hear what she says. It’s always scary to try alternative options when doctors don’t always agree. Ugh!

Thanks for that. I.v checked with my doctor and oncologist and it's fine , to take vitamin b complex.

Wanted to mention about B vitamins. I happened to have a brain MRI and follow up with a neurologist at MD Anderson. The MRI was done because I was having 24/7 headaches and they could not find a reason for it - and having breast cancer 1 year before they wanted to eliminate possible metastasis to the brain. Sorry long background story - Anyway no tumor (yea), but the neurologist told me to NOT take a vitamin B6 supplement because I was within normal range of this type of B vitamins and taking too much B6 could actually harm my brain, not help. She told me to limit my B12 supplement to 6 months. I was a little low on B12 but again she did not want me to take too much. I was really surprised because everything I read always encouraged B complex.
So you might want to be careful with taking vitamin B.

This is quite interesting Rubyslippers as I am taking both...the B6 for my migraines and B12 b/c my former PCP felt my blood level (although in the normal range) could use a boost. I am now rethinking these supplements. I am glad you mentioned what medical center the neurologist was affiliated with - MD Anderson is tops.
Knowing this makes me think I should stop the B6 and 12. My migraines can be relentless and my neurologist says I have "refractory" migraines (meaning very hard to treat)...and my heart disease stops me from taking the triptans so I have to go with the CGRPs - which are only minimally effective. And I was just diagnosed with breast cancer...try to find my initial post which was just the other day to hear my story. Thanks for your input, very helpful. Be well.

@briarrose Well, we may have different issues so maybe check before stopping? My neurologist was concerned with tumor growth and my non-migraine headaches. She diagnosed me with mild peripheral neuropathy based on an inability to sense vibration in my large toe. I also have lost knee reflexes (who knew) - you know when they tap your knee with a rubber mallet- I have no knee jerk response!! So weird. So neurologically I may have different issues.
(guess those ruby slippers aren’t exactly helping my feet!)

what is your neuropathy from?
i was tripping and found i had foot drop. went to pt. i have anxiety and recently taking zoloft i’ve been doing exercises but now i found my hand gets numb in the morning and i feel funny from my wrists to my elbows and don’t know what’s going on. my oncologist quit me so only see pcp who is nice but i don’t know if she can help much.

I recently 1/26/26 starting taking 20mg Tamoxifen. I seem to have a little trouble focusing and initially thought it was the combined events of downsizing, moving across country, lumpectomy in November, 5 treatments of radiation, the holidays, and accounting projects.

Wondering if anyone is taking supplements like B12 or Magnesium? Or other tricks.

I too had brain fog on 20 mg of tamoxifen. I found the effects keep changing somewhat, warm flashes gone, moodiness up, until about 3 months after starting. I was functioning okay, but not initiating anything new - not making new plans or starting new projects.
I think there is probably some settling in that happens, so your brain fog may lift.
I ended up seeing an oncology neurologist at the cancer center. After looking at my bloodwork, she said I could take B12 if I wanted to but for no longer than 6 months. She said I should not take B6 as I was high enough and it’s a problem to take too much, so if I was taking B12 to not take a B complex pill. She was okay with magnesium, but it was not something she felt would make a difference for me. Guess taking the supplementals would depend on what level you're at now.
The conclusion, for me, was that the tamoxifen was causing the headaches I had. I tried a 30 day holiday, then back to 20, then 10 mg, now on 5. It was this experience that made me realize how the drug effects changed over time, and that at 3 months seemed to be the length of time it took for side effects to stabilize.
Many women do okay on 10 or 20. There are studies that show that 5 mg should be enough, but not that many. Usually guidelines and protocols are not adopted unless there are multiple studies that can replicate the findings - that prove that the original study wasn’t a fluke.

I’m hoping that 5 is enough. There is no drug manufacturer that makes a 5 mg pill - which makes me think they are not going to invest their money into providing a pill that hasn’t been proven yet.
I’ve been taking tamoxifen 3 years. Last year a CT scan picked up small pancreatic cysts, now being watched at the cancer center. There is some current research being done on tamoxifen and PC, as it is believed that it weakens the surrounding tumor environment for adenocarcinoma. So it could be that the tamoxifen is helping me in multiple ways.