Come join others currently navigating treatment in our weekly Zoom Meetup! Register here: Tuesdays, 1pm ET.
Fill Out Your Profile to share more about you. Learn more...

Mushroom Extracts and Letrozole?

B-A-P Member Posts: 409

Hi everyone!

Currently On tamoxifen but will be switched to Letrozole after my oophorectomy. MY naturopath suggested I take mushroom extracts to help prevent recurrence and boost the immune system . She warned me that my oncology pharmacist is going to tell me not to take it. I think Mushrooms have an aromatase/estrogenic action? I can't remember what she said.

Anyone here on letrozole and taking mushroom extracts? Have your doctors given the okay or warnings?

I think it would be super beneficial to take it but obviously if there's a huge contraindication then I would reconsider.



  • husband11
    husband11 Member Posts: 1,287

    My wife is stage IV and switched to letrozole and ibrance and it has been very effective for two years now. She has been on various mushroom extracts the whole time. Mostly maitake D extract at 5mg/kg body weight/day. She went on it 5 years after chemo ended and she saw a tremendous boost in her neutrophil count. Over doubled her neutrophil count after having been depressed for 5 years.

    I have never read anything contraindicating most mushroom extracts for HR+ breast cancer patients. Some might exist, but most, like maitake, ahcc, shitake have no negative interactions that I have read of, aside from lowering of blood sugar levels and allergic reactions in some patients, and I have read quite a bit on the subject for years.

  • jsniffs
    jsniffs Member Posts: 136

    I'm on Letrozole, and I take Stamets7 (a mix of 7 mushrooms). The Stamets7 was suggested by my integrative oncologist, and my MO had no issues with it. In fact, I think some mushrooms have an anti-estrogen effect.

  • dtad
    dtad Member Posts: 771

    Hi everyone...I take mushroom extract supplements. Its one of the ingredients in Breast Defend that I take in leu of an aromatase inhibitor. I agree that these mushrooms have an anti estrogen effect and that's why they are in Breast Defend. Good luck to all.

  • B-A-P
    B-A-P Member Posts: 409

    Thanks Everyone :) If anyone else is taking them together I'd love to hear about it. I think I will go with her suggestion. I've read so much good and haven't found anything to suggest otherwise any negative interactions.

    I appreciate the replies :)

  • olma61
    olma61 Member Posts: 1,016

    This is not a direct answer to your question but be aware that the mushroom immune supplements can cause serious itchiness, liver toxicity and other side effects. My experience: I started taking "Mushroom Defense Formula" from Amazon at the same time I started chemo & herceptin/perjeta (without telling my doc, of course). Benadryl was part of my pre-meds but still, I was experiencing terrible itching on my back, so bad that I was scratching til I bled. H&P can also cause itching, but I found out itchiness was also an SE of mushroom supplements. I discontinued the mushrooms and the itching stopped. I tend to think the itch was not from H&P but from the mushrooms. This was really BAD itching, not just a little annoying.

    Here is a list of side effects from WebMD for reishi mushroom supplementation:

    Here is the specific brand I was taking on Amazon. It contains five types of mushroom plus BetaD Glucans:

  • B-A-P
    B-A-P Member Posts: 409

    thanks for your input Olma!

  • totallytubular
    totallytubular Member Posts: 17

    hello, I am on Arimidex and my integrated oncologist at Sloan Kettering ok'd mushrooms that I am taking. I guess there are many types of mushrooms.. so I am not sure about all. I couldn't take maca or rhodiola. best of luck to you.

  • ahccuser
    ahccuser Member Posts: 1


    I registered on this website as I found via google some people wondering about mushroom effects on aromatase inhibitors.

    Here is my story:

    Upon my advice, my girlfriend took approx 6 month AHCC capsules, that is shiitake mushroom improved for better gut assimilation, at the dose of 3g/day trying to clear HPV virus. At the end of the 6 month she felt something in his belly, and she was diagnosed uterine fibroid of 7cm which is a benign tumor sensitive to estrogen/progesterone. This tumor never stopped to grow and it has been removed surgically by laparotomy 3 month ago.

    So I am here to say that maybe AHCC (shiitake mushroom extract) could promote estrogen, as this kind of tumour grow with estrogen, and the same thing could thus occur in the case of breast cancer, be watchful. There is also a possibility that these events are pure coincidences but it is worth thinking about it. My girlfriend has also a Mirena IUD for several years it could be another cause.

    "Immunoassay data suggested that AHCC is a potential inducer of aromatase activity."