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Ep 6: Are Parabens Actually as Dangerous as We've Been Told?

Updated: Nov 29

Last week we chatted about preservatives which are the ingredients that keep water-containing products from growing bacteria, yeast, and mold. This week, we’re discussing a specific type of preservative, called parabens: what they are, why chemists used them for a century, how a flawed 2004 paper (the Darbre study) set off years of fear, and what the actual data say about “estrogenic” risk.


We'll talk about whether or not parabens cause cancer, discuss hazard versus risk, and explain why many paraben replacements are more irritating and less well-studied. By the end of this episode, you’ll understand the truth about parabens and avoid the “preservative-free” trap that can make products unsafe.


Before we get started: 


Before we get started, massive shoutout to Dr. Michelle Wong, a cosmetic chemist with a chemistry PhD, and Dr. Andrea Love, an immunologist with a PhD in Microbiology and Immunology, for the incredible work they’ve done regarding parabens; I used their articles for my research quite a bit, and they’re extremely well researched and well written. I highly recommend that you read these articles, as well as the other articles that these two scientists have published. They’re amazing resources for scientific information. Links to their articles are included in the description of this post.




What are preservatives? (a recap)


Preservatives are something that preserves or has the power of preserving, specifically "an additive used to protect against decay, discoloration, or spoilage." They’re used in all sorts of products like food, cleaning products, detergents, pharmaceuticals and cosmetics. In cosmetics specifically, they’re used in products that contain water to protect the product from bacteria, fungus, and other microorganisms.


What are parabens?


Parabens are a preservative family used to keep products from growing bacteria, yeast, and mold. Although they're rarely used anymore, if you do see them on a label, you’ll most often see methyl-, ethyl-, propyl-, and butylparaben, though others exist (isopropyl-, isobutyl-, pentyl-, phenyl-, benzyl-). Different members shine under different conditions and target different microbes, so formulators often pair them up for broader coverage.


They’ve been in use since the 1920s. They’re inexpensive, work at tiny amounts (around 0.1% can fully protect some formulas) and cover a really wide range of organisms. After nearly a century of use, the only consistently documented downside is allergic reactions. Those are uncommon and show up mostly on already-compromised skin (think wounds or eczema).


Why are parabens useful?


Parabens were first used in the 1920s, so we have a ton of data on them; they are some of the most well studied cosmetic ingredients we have. They’re great because they’re cheap, effective at very low concentrations, and are often broad spectrum. 


A discussion about hazard vs risk


When we’re having these sorts of discussions, it’s really important to understand the difference between hazard versus risk. A hazard is something that can cause harm, and the risk is the chance of harm depending on the exposure and the dose. Here’s an example:


A hot stove is a hazard. It’s something that could cause harm to you. However, you only get burned if you touch it; the risk depends on whether or not you touch it, how long you touch it, if you touch it with just your finger versus your whole hand, if you’re using a pot holder, etc. The hazard remains the same, but the risk can vary drastically depending on the situation. 


People often look at something that’s a hazard and immediately write it off; however, the risk is the most important part of the equation. 


The story of the Darbre Study


In 2004, the Journal of Applied Toxicology ran a paper known as the Darbre study (Darbre was name of the main author on the study). In the study, the authors measured parabens in 20 frozen samples of human breast tumors. They used analytical chemistry to quantify different paraben levels in those tissues, and basically concluded that parabens could cause cancer. The study was badly done and never should’ve cleared peer review. However, the study used buzzwords like “hormones,” “chemicals,” and “cancer," which drew a lot of attention to the article, especially for that time period.


Issues with the Darbre Study


The study had several glaring issues, such as:


  • Tiny study: A sample size of 20 is very small.

  • No controls: They didn't use any healthy breast tissue for comparison, so any “link” to cancer is just speculation.

  • Presence ≠ causation: The data only show tiny amounts of parabens in tumors, not how they accumulate, how they progress over time, or how different levels of exposure effect the amounts found.

  • Trace amounts: They found anywhere from~0 to ~13 ng/g (aka parts per billion) of parabens in breast tissue. For comparison, that’s like one second in 31.7 years.

  • Contamination red flags: They used blanks, which had amounts of parabens often as high as - or sometimes even higher than - the samples they were testing, suggesting the readings may be instrument noise, not actual levels of parabens in the samples.


Darbre Study Concerns


After that paper, fear took off. Many people came to believe parabens were tied to cancer—even though the study was poorly designed. A common claim that stuck was “parabens are estrogenic.”


Before we continue, it's important to know how hormones work. Hormones are chemical messengers. Glands release them into the bloodstream to cue cells to act, and do things like grow, use energy, store fuel, make milk, handle stress, regulate temperature. To trigger anything, a hormone has to dock with a receptor. It's basically a lock-and-key: the receptor is the lock; the hormone is the key. Examples of hormones are insulin, adrenaline, testosterone, and estrogen.


When we call something “estrogenic,” we mean it can mimic estrogen’s signal. It can turn on some of the same pathways—cell growth, maturation, survival. It isn’t the perfect key, but it can jiggle the lock enough to register a signal. That can be a problem.


Why? Doses and timing matter. A mimic can create a constant “on” signal that scrambles the body’s rhythms. Mimics can also hog receptors, blocking real hormones from binding. And if the body reads a “high estrogen” signal from the mimic, the brain may dial down natural hormone production.


So, estrogenic compounds sound scary. But here's the thing: parabens are very weak mimics.


Parabens bind the estrogen receptor thousands of times less strongly than estradiol (your main endogenous estrogen).Depending on the paraben, you’d need roughly 10,000–100,000× more to produce a similar receptor response as the same amount of estradiol. Real-world cosmetic use doesn’t approach that territory, so receptors don’t meaningfully “switch on.”


For cancer risk context: ethinyl estradiol (the estrogen in many oral contraceptives) is about 2,000,000× more potent than butylparaben, and even that medication is linked to only a small increase in risk.


What happened after the Darbre study?


After that study, misinformation absolutely exploded. Consumers started to demand that brands go “paraben-free,” and many brands swapped parabens for less-studied, more irritating preservative systems. Basically, a safe, well-understood tool got replaced because people were afraid of it.


The most obvious cautionary tale is the “Itchy M’s”: methylisothiazolinone and methylchloroisothiazolinone (say those five times fast). Patch-test data show allergies around ~10%, versus ~1% for parabens.


Other stand-ins - like phenoxyethanol and some formaldehyde donors - can also irritate more than parabens, and we lack long-term data for many alternatives. However, these alternatives are still safer and more effective than nothing at all. Some companies have begun to skip preservatives altogether, which is a great way to seriously injure yourself by using unsafe cosmetics, so please don’t.


Basically, mountains of research haven’t shown a causal link between parabens and negative health outcomes.


Some quick math for you, done by Dr. Andrea Love in this article: Regulators have set an acceptable daily intake (ADI) of 10 mg/kg/day for parabens. For a 70 kg (154 lb) person, that’s 700 mg/day of parabens. Cosmetics typically use 0.01–0.3% parabens. If you applied one travel size bottle of lotion per day, with anywhere from 10–300 mg total of parabens, only about 1–10% of the parabens would maybe be absorbed (0.1–30 mg). That’s still far below 700 mg/day - you could basically eat 670 mg of parabens on top of one full travel-size bottle of lotion per day for the rest of your life, and still be fine. Normal use doesn’t even approach risky exposure.


So yes, parabens are a hazard (like a hot stove). But risk depends on dose and exposure. In everyday cosmetic use, the risk is extremely low. The hazard made headlines, while the risk got ignored.


The end of an era


Because of the Darbre study, parabens have been essentially removed from cosmetics; these days we rarely see products using parabens as their preservative system. This study singlehandedly changed the beauty industry and forced formulators to pivot. 


This goes to show how important scientific literacy is, and understanding that not all science is good science. Listening to experts is incredibly important; countless experts (like Dr. Wong and Dr. Love) have reviewed these studies and determined that parabens are safe and effective, and we are worse off not using them - but because fear sells and misinformation spreads more rapidly than the truth, these experts are often ignored and sometimes even accused of "ulterior motives”. 


It’s so important to get your information from reliable resources; I highly recommend that you follow trustworthy scientists and get your information from them. We’ll have a list of our favorite creators below, please follow them and support their content.


Conclusion


So, in conclusion, parabens are not the spooky ingredients you’ve been told they are - instead, the fear of parabens has haunted the cosmetic industry. Parabens are long-studied, effective, broad-spectrum preservatives that work at very low levels. The best evidence does not link them to breast cancer or meaningful hormone disruption in real-world use. The 2004 Darbre paper changed public opinion, not the science—and the shift away from parabens often pushed brands toward systems that are weaker, more irritating, and less proven.


Safe cosmetics need preservation, full stop. Good risk assessment weighs potency, dose, exposure, and evidence quality. Support creators and scientists who cite sources, explain uncertainty, and correct mistakes. We’ve included trusted reads from Dr. Wong and Dr. Love, plus more resources, down below. Share them, ask better questions, and let’s reward good science over fear.


Trusted Sources


Here are some of the main sources we recommend, among others!



Bibliography



 
 
 

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