From "Shrinking Penis Syndrome" to PCOS - Endocrine Disruptors Part 1

From "Shrinking Penis Syndrome" to PCOS - Endocrine Disruptors Part 1

Hillary Lin, MD


Hillary Lin, MD


Mar 26, 2024

A growing environmental health epidemic

(Hopefully, this subject line made it through your email filter.)

This week’s news broke a study that identified over 900 chemicals that could contribute to breast cancer development. Nearly every chemical was found in everyday consumer products, food, drinks, pesticides, medications, and workplace environments.

This overwhelming number can make a person give up before even trying to understand and take action.

This sign was so prevalent when I lived in California that I developed a kind of notification blindness to it.

However, my post today is about how much control you actually could have over prevalent and harmful health conditions, from erectile dysfunction to obesity. I highlight particular concerns for pregnant mothers-to-be since they have a unique responsibility for a new generation of health and hurt (I’m sorry).

For Part 1 of the DH3 Dive into endocrine disrupting chemicals (EDCs), I will focus on those substances that harm or disrupt our reproductive system. Roughly speaking, this involves estrogen, testosterone, pregnancy, menopause, muscle building, erectile function and dysfunction, and diseases such as cancer. By the end of this read, you’ll understand:

- What are endocrine disruptors?

- How low testosterone might be a result of our modern environment.

- Why we’re seeing increasing issues like PCOS, certain cancers and birth defects, and obesity.

TLDR: If you’re worried about low testosterone, erectile dysfunction, fertility, miscarriages, and cancer, then learn about and avoid endocrine disruptors that are commonly found in plastics, shampoos, weed killers, fragrances, and cosmetics. You can use the DH3 GPT (work in progress) to determine if your product has an endocrine disruptor.

Endocrine Disruptors — Pervasive, Everyday Enemies

The simplest definition of an endocrine disruptor is a substance that interferes with human and animal hormones. Duh, I know. This video by the Endocrine Society is pretty good if you want a 3-minute video primer on endocrine-disrupting chemicals (EDCs):

Reproductive Health Disruptors

One of the most concerning effects of EDCs is how they’re changing our male and female functions and characteristics, including puberty and fertility. In men, reproductive EDCs can cause erectile dysfunction, lower sperm counts, and growth of abnormal breast tissue. In women, they can lead to irregular menstrual cycles, early menopause, reduced fertility, and increased reproductive system cancers.

This category of EDCs profoundly impacts fetuses and children via their pregnant mothers as well. Not only do they result in a higher risk of miscarriages, but they can also lead to congenital anomalies (such as heart defects, cleft lip, and limb deficiencies) and developmental issues (such as autism spectrum disorders, ADHD, and growth delays).

(It’s worthwhile to note that all the energies of people angry about vaccines potentially causing autism might be better directed toward the true villains — endocrine disruptors.)

Reproductive EDCs are omnipresent, so I tried to make it easier to understand how to detect and avoid them with this table.

*The EU banned BPA in thermal paper (receipts) starting in January 2020, although there is concern about BPS (bisphenol S) replacing BPA in thermal paper. The best option is to avoid getting printed receipts at all! Stick to digital receipts if you need them.

Not to get too deep into thermal paper, but a study on the topic showed that when people hold thermal receipt paper immediately after using hand sanitizer, there is a more significant transfer of BPA into the skin and onto food (then eaten). So take special care when checking out at the food counter 👏.

Low Testosterone — Erectile Dysfunction, Low Sperm Count & Quality

Low T results in a host of problems like ED, low libido (in men and women!), worse sperm count and quality, fatigue, depression, and trouble building muscle.

I wrote about low testosterone first due to the relative lack of awareness in males about the harmful effects of EDCs in their bodies. Some advocacy has resulted in “clean” marketing across soaps, cosmetics, and cleaning brands oriented toward women but fewer brands catering to men. While women certainly (unfairly, haha) have a more significant burden of watching out for EDCs due to our potential to become pregnant, there is a real and present risk for men’s health and function.

“Shrinking Penis Syndrome” — A Special Note on Plasticizers

When I was in Taiwan about a decade ago, a considerable scandal surrounded food, drinks, and supplements containing plasticizers. Plasticizers, or phthalates (see table above), are used in many products, from cosmetics to toys. Their use in beverages was to maintain a homogenous (smooth) texture so that different ingredients would not settle out unappetizingly. But drinking even one serving of a contaminated beverage would expose a person to 7x the recommended limit of plasticizers.

Phthalate contamination was so extensive that entire categories of foods and beverages were pulled from the shelves in 2011. Btw, not even bubble tea (boba) was safe! (Photo by Manny Calonzo)

Are You Pregnant?

These drinks (which, by the way, were exported all around the world) were especially harmful when consumed by women pregnant with male fetuses due to phthalate syndrome. Potential results of exposure include:

- Cryptorchidism or undescended testes

- Hypospadias (where the opening of the penis is in an incorrect location)

- Impaired sperm quality

- Reduced testosterone production

In case there is any confusion, penis shrinkage in this context refers to shrinkage over generations since there’s no evidence of phthalates causing fully-grown penises to shrink in size. 🙄

This link is more clearly documented in a study conducted in Mexico, where pregnant women provided urine samples for phthalate measurement, and those with male infants followed up for further analysis. There was a statistically significant inverse association noted where the higher levels of maternal urine phthalates were associated with a shorter distance from the anus to the penis base (the taint), decreased penile width, and shortened penile length.

Not Just About Genitals 🍆

There are additional concerns about brain development that can affect intelligence and behavior. Finally, there’s an increase in chronic diseases like obesity, diabetes, and asthma.

People were plenty mad in Taiwan about this, so thankfully, the government tightened enforcement and effectively eliminated plasticizers from their food and beverages. However, we still see EDCs in so many everyday products in the US and the rest of the world that I wonder about the relative lack of outrage and regulation here. It truly feels like phthalates are in everything, everywhere (all at once!): fragrances, plastic food containers (Tupperware and disposable take-out boxes), disposable plastic utensils, water bottles, medical devices, disposable gloves, and even drinking water.

A Need for Advocacy

The reality is that we need tighter government control since the current regulations are not strict enough. Not only are we seeing problems with genital development, but health concerns, including obesity, diabetes, thyroid dysfunction, high blood pressure, neurodevelopment delay, allergies and asthma, and certain cancers, are all results of phthalate exposure.

PCOS — More Common Than You Thought

Polycystic Ovary Syndrome (PCOS) is a complicated endocrine disorder with varied symptoms from irregular menstrual cycles, multiple cysts growing in the ovaries (thus the name), insulin resistance (leading to diabetes in some cases), and elevated levels of androgens (such as testosterone). The high androgen levels lead to symptoms such as scalp hair loss and inappropriate male-pattern hair growth (hirsutism), such as on the upper lip or chin.

Diagnoses of PCOS have increased over time, and it’s unlikely this is simply due to greater awareness. Although there are debates about how to diagnose the condition accurately, three studies show that over 1 in 5 women suffer from the syndrome. Notably, the clinical criteria (known as Rotterdam criteria) require only 2 of the following 3 conditions: oligomenorrhea/anovulation (few periods or lack of ovulation), clinical/biochemical hyperandrogenism, and polycystic ovaries. (This means that one might not even have the cysts and still technically qualify as having PCOS!)

Send for Help!

In my clinical practice as a PCP, I have seen an enormous number of women with undertreated PCOS. There are options such as spironolactone and combined oral contraceptives (covered in a prior newsletter issue) to counter the hormonal effects and metformin or GLP-1 agonists (semaglutide AKA Wegovy or Ozempic) to counter insulin resistance and weight gain.

A Different but Related Culprit

As you might have guessed, there is substantial evidence linking PCOS to EDCs, particularly Bisphenol A (BPA). BPA concentrations are higher in women with PCOS compared to those without. Levels of BPA are also positively correlated with hyperandrogenemia.

Contrary to what you might think, BPA does not “look” like testosterone to the body. Instead, it has partial estrogenic function and binds to specific estrogen receptors but not all. BPA is commonly found in ovarian follicular fluid since BPA gets pulled into the usual pathways involving estrogen. It thus indirectly causes overproduction of androgens by the ovary.

BPA has been shown to disrupt metabolic activity by promoting more adipocyte differentiation (fat cell formation) and activating glucocorticoid receptors, thus converting more precursors to cortisol and promoting adipogenesis via multiple pathways. BPA also causes pancreatic beta-cell dysfunction, thus promoting insulin resistance. These effects explain the difficulty many PCOS sufferers also have in a lifelong battle against insulin resistance and increasing adipose tissue.

We’re Cursed

Since this is getting long, I will wrap up this week’s post by noting that studies also link phthalates and BPA to decreased libido. So the curse of EDCs starts with low interest in sex, continues with problems with sexual intercourse (ED), results in multiple pathways of issues with conception (anovulation, poor sperm count and quality), promotes developmental issues during gestation, leading to miscarriages and congenital birth defects, creates problems with brain and physical development, and finally results in a shortened reproductive window (due to earlier menopause).

Pretty stark.

What Do I Do With All This Info?

After writing this piece, I realized there wasn’t a good way to check one’s ingredients against lists of endocrine disruptors. So, I configured a quick GPT with a clunky name — DH3 Health Guide — for educational and entertainment purposes only (not medical advice!). It checks your product and ingredients against the EU’s list of endocrine disruptors because Europe seems to care way more about its citizens than the US. Please send your suggestions for improvement since it is a work in progress.

There’s so much more

I wanted to share an incredible amount of additional research in today’s issue, but you’ll have to wait until next week 😄. Thanks for reading this far! Your brain is growing smarter 🧠.

A quick request — please send me suggestions for how to improve, and keep sending in your topics of interest and burning questions. I’m only just beginning!

Cheers to your health,

Hillary Lin, MD

P.S. I promise this is the real end of this post — but I couldn’t stop sharing the provocative and revealing work of Dr. Shanna Swan, a reproductive epidemiologist. Her work dives into what I briefly introduced and raises even bigger questions about gender fluidity effects (!).

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