Phytoestrogens Are Not a Duck: Low Estrogen, Thyroid Disruption, and Amenorrhea

After a few months of missed periods that could only be explained by my diet or else immaculate conception, I went to see an Ob/Gyn. He suggested several blood tests, and the results came back thusly: low estradiol and low T3. Let’s break it down:

“Estrogen” as we know it is really just an umbrella terms for several estrogenic hormones, estradiol one of the most important. It’s the estrogen that regulates much of the processes of fetal development, as well as the distribution of body fat and growth of the breasts and genitals.

Estradiol is used to treat post-menopausal women so that they don’t suffer from things as annoying as hot flashes to as life-threatening as osteoporosis. My ob/gyn took it upon himself to prescribe me a synthetic estradiol to prevent these post-menopausal symptoms from happening to me. (We’ll get back to what happened with that in a second.)

As I mentioned last week, bombarding your body with excess phytoestrogens (like those from soy) can cause your body to stop making its own estrogen because the phytoestrogens bind to hormone receptor sites and trick the body into thinking there’s sufficient estrogen around.

But phytoestrogens can’t manage all of the functions that endogenous (or “made inside the body) estrogens are supposed to handle. (This is one of those “what looks like a duck, walks like a duck, quacks like a duck, but isn’t a duck?” situations.*)


And one of those things that estrogen is supposed to do that phytoestrogens can’t is signal the production of T3.

T3 is one of the thyroid hormones, which has a direct effect on important processes like metabolism, heart rate, and mental health. According to Dr. Christiane Northrup, T3 is actually a neurotransmitter that affects serotonin, norepinephrine, and GABA–the latter of which regulates things like anxiety. Suddenly the depression and anxiety don’t seem so random!)

Cases of low T3 can lead to a syndrome like hypothyroid, in which the thyroid gland itself stops working properly. This is can have an effect on menstruation (among other things) as the ever amazing Stefani Ruper of PCOS Unlocked explains:

“Hypothalamic amenorrhea is a problem of being too stressed, eating too few calories, exercising too much, and having too little body fat.  In essence, it is a condition caused by hypothalamic stress and down-regulation.  Hence the name….[Because if you restrict] calories or [exercise] excessively, [your…] estrogen levels drop.  The hypothalamus perceives this drop as an indication of a time of famine, and initiates a starvation response, primarily by decreasing the production of sex hormones.”

In other words, if your thyroid isn’t working, then your period stops.

Now, I wasn’t presenting all of the symptoms of hypothyroid, nor were my low levels of T3 considered significant by my Ob/Gyn, but now that I look back on it, things make total sense: I was estrogen dominant because of the phytoestrogens, and yet my actual estrogen levels were significantly low. My phytoestrogen dominance was causing my T3 to lower, just as my anorexia had caused it to lower in the past. My metabolism was slowing, so I was putting on weight. My brain chemicals were thrown off, so I was suffering from a relapse of the depression and anxiety (both of which fuel ED).** And, of course, my estrogen production was further affected (vicious circle that it was), and so I stopped getting my period.

Moreover, the hormonal imbalances from low estrogen, hypothalamic amenorrhea/estrogen dominance, and low thyroid cause…acne! (Which will lead us to an update on how the hormone rebalancing is going and my current struggles to end the vegan-induced acne from hell next week!)

Stay hungry,


*The answer is obviously: phytoestrogens are not a duck. But I digress.

**Also why I started withdrawing from my friends at the Fruit Stand, and why things had started going downhill with my roommates…


PCOS Unlocked

P.S. As always, if you’re interested in learning more about PCOS, fertility, and the wide world of hormones, I definitely recommend that you check out Stefani Ruper’s PCOS Unlocked. I read it, I love it, and I highly, highly recommend all of her work–Stefani hasn’t asked me to promote the book+ (she has no idea who I am–although, Stefani, if you ARE reading this, know that I love and appreciate all of your work!), but I’m definitely happy to point others in her direction. If you can’t afford an ebook now, at least check out all of the free content she has on Paleo For Women. It’s a little science-y, but she makes it fun, understandable, and accessible.

+Just an FYI, I’m promoting the book of my own accord, because I honestly believe that there’s a lot of important, well-written, and useful information offered inside, but I do make a couple of shekels if you choose to purchase the book using the link I provided.

2 thoughts on “Phytoestrogens Are Not a Duck: Low Estrogen, Thyroid Disruption, and Amenorrhea

  1. Hi. I saw your question for Sean’s show on facebook. I’ve had personal experience with acne and missed periods, as well as ovarian cysts. For the time of about a month a few years ago, I was very strict following Mark Sisson’s suggestion of keeping carbs below a certain level and completely removing grains. My level of acne is mild to moderate, but it cleared up EVERYWHERE (face, neck, chest, back) after only a month. Of course, this is just my experience, others will have different levels of success.

    This may be helpful for you – research iodine in relation to acne and reproductive health. You should be able to find interviews and other info with Dr. Jorge Flechas and Dr. David Brownstein.

    hope this helps 🙂

    • Thank you so much for your reply! I’ve actually been very low carb for a few months now–I’ve even given up all fruit except for some berries in the evening. I eat sea veggies almost every day for the iodine (and because they’re darn tasty!)…but I will definitely look up the docs you mention–any information helps! Thanks again 🙂

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