They've been in your toothpaste, moisturizer, and shampoo for nearly a century. But "decades of use" is not the same as "proven safe", and the science is catching up.

If you’ve ever scanned a toothpaste label and spotted long words like methylparaben or propylparaben, you may have wondered:

Are these ingredients actually harmful, or is this just another “clean beauty” scare?

There seems to be an open debate about parabens. Regulatory agencies consider them safe at current use levels. Meanwhile, a growing body of laboratory, animal, biomonitoring, and mechanistic research raises legitimate concern; particularly around hormone disruption and cumulative exposure.

Let’s unpack what we really know.

What Are Parabens, Exactly?

Walk into any drug store, pick up a bottle of shampoo, a tube of toothpaste, a jar of moisturizer, and there's a very good chance you'll find parabens on the label. Synthetically produced, commercial parabens are alkyl esters of para-hydroxybenzoic acid, and they have been used as preservatives in cosmetics, pharmaceuticals, and food since the 1920s. Their appeal to manufacturers is simple: they are cheap, stable, highly effective against bacteria and fungi, and they extend product shelf life dramatically, up to five or ten years.¹

In the EU, parabens may also be labelled with E-numbers when used in food products. Here are common parabens you may see on your toothpaste labels:

Methylparaben (E218)
Propylparaben (E216)
Ethylparaben (E214)
Butylparaben
Benzylparaben
Heptylparaben (E209)

Because toothpaste and mouthwash are water-based products, they are particularly vulnerable to microbial contamination. Parabens are used to prevent the growth of bacteria and fungi in these formulations, keeping the product stable from the factory to the bathroom cabinet. Methylparaben and propylparaben are the forms most commonly found in oral care products. According to the FDA, methylparaben may appear at concentrations of 0.015–0.2% and propylparaben at 0.02–0.06% in toothpaste formulations.²

In short, parabens exist for one reason: to keep products shelf-stable and microbe-free.

So why the controversy?

The Core Concern: Endocrine Disruption

Parabens are classified as endocrine-disrupting chemicals (EDCs), and more specifically, as xenoestrogens, synthetic compounds that can mimic estrogen in the body. Estrogen is a hormone that plays a critical role in everything from reproductive health to cancer regulation, by binding to estrogen receptors in cells.

Even if most toothpaste is spat out, some paraben residue is absorbed through the oral mucosa (inner mouth lining) or swallowed. Research indicates that the oral lining is highly permeable. Therefore, parabens that enter this way bypass the digestive metabolism that would otherwise break them down, meaning they may enter the bloodstream relatively intact.²

A landmark 2018 review published in Molecular and Cellular Endocrinology confirmed that parabens interfere with receptors for androgens, estrogens, progesterone, and glucocorticosteroids.³ Enriched with a variety of endocrine receptors, the prostate gland within the male reproductive system produces semen, the liquid that nourishes and transports sperm. Studies have found that the accumulation of parabens in prostate tissue is linked to BPH (benign prostate hyperplasia, aka. enlarged prostate) as well as an increased risk of prostate cancer.^4,5,6,7

It’s the cumulative effect that is of concern. On any given day, a person who uses conventional personal care products is likely exposed to several parabens simultaneously through skin absorption, inhalation, and ingestion of food additives.¹ Plenty of evidence shows that parabens in the body accumulate from skin contact via cosmetics, and are linked to male reproductive development and breast cancer in females.⁸

What About Cancer Links?

Paraben exposure from personal care products is linked to higher occurrences of prostate cancer^9,6,10,, but perhaps the most troubling body of research concerns breast cancer. Parabens have been detected in human breast tissue and breast tumours.¹¹ Exposure to estrogens and to some xenoestrogens has been associated with cell overgrowth and an increased risk of breast cancer.¹² A review on parabens and breast cancer found that parabens can modulate local estrogen-converting enzymes and increase local estrogen levels in breast tissue, a mechanism directly relevant to estrogen-receptor-positive breast cancer, which accounts for approximately two-thirds of all breast cancers.¹³

Critics argue that these types of studies do not imply causation. The International Agency for Research on Cancer (IARC) has not evaluated any common parabens nor classified them as carcinogenic to humans. The U.S. FDA and Health Canada state that parabens do not pose a health risk at current levels of exposure in cosmetics and foods. However, the EU’s Scientific Committee on Consumer Safety (SCCS) does outline limits to specific concentrations of parabens to prevent potential endocrine-disrupting effects.^14,15

In short, regulatory agencies are not taking strong actions against paraben use. Yet, a 2025 cross-sectional study in Nature’s Scientific Reports analyzed data from 4,455 subjects in the National Health and Nutrition Examination Survey and found statistically significant associations between urinary paraben concentrations and breast cancer outcomes, reinforcing that biomonitoring in humans shows some evidence of the relationship.¹⁶

The striking REDUXE study demonstrated that healthy women who stopped using paraben and phthalate-containing personal care products for just 28 days showed a reversal of cancer-associated gene expression patterns in their breast tissue. This suggests that ongoing paraben exposure was actively pushing normal breast cells toward a pro-carcinogenic state.¹⁷

For many scientists, experts and clinicians, this current body of evidence justifies taking a precautionary approach, especially when safe, paraben-free alternatives are available.

Myth Busting

Myth #1: We've been using parabens for decades. If they were harmful, we'd know by now.

One can think of many examples of substances that were used for decades while they were unsafe: mercury for hat-making, lead in pipes and paint, asbestos in building materials… just to name a few.

In each case, the harm was present long before official acknowledgement caught up. Duration of use is not evidence of safety. It is more often simply evidence of inertia, regulatory lag, and the enormous commercial pressure to keep cheap ingredients on shelves.

The science on parabens has only relatively recently developed the tools to detect endocrine disruption at low doses, and that science now raises serious concerns^.18

Myth #2: There's no data on humans showing parabens are harmful

This statement is just false.

Although there is a lot of good animal data¹⁹, and plenty of in vitro studies done on human cells, there are also extensive biomonitoring studies on human excretions and biopsied tissues showing the links between paraben exposure and the growth of cancer cells.

Multiple studies on human cells have collectively shown that parabens bind to estrogen receptors and drive the proliferation of breast cancer cells.^{20,21,22,23,12,24}

A study that measured paraben concentrations in breast tissue removed from 148 cancer patients found that malignant tumours contained nearly three times the paraben levels of healthy tissue.²⁵ Coupled with the evidence of links to prostate cancer⁶, research has shown paraben accumulation tracks alongside hormone-sensitive cancers in both women and men.

Epidemiological studies have also linked paraben exposure to gestational diabetes²⁶ and shortened menstrual cycles²⁷.

Myth #3: Regulatory bodies say parabens are safe, so they must be fine

Regulatory bodies are not static authorities with perfect knowledge. They respond to science over time, under significant industry pressure, and with varying levels of precaution.

The EU has already banned several parabens (e.g. butylparaben and propylparaben are prohibited in products for children under three) and classified others as priority endocrine disruptors. The FDA, by contrast, has not acted; however, the early "GRAS" (generally recognized as safe) classification was made before modern endocrine disruption science existed.²⁸ Regulatory approval reflects what was known and politically viable at the time of the ruling, but it is not a guarantee of long-term safety.

What Do Regulators Say?

The U.S. Food and Drug Administration (FDA) states that parabens are safe in cosmetics at current use levels, based on available data.

The European Commission has restricted certain longer-chain parabens and set concentration limits for others.

Regulators tend to evaluate ingredients individually and at specific concentrations.

Critics argue that this approach does not account for:

Cumulative exposure from multiple products
Lifelong low-dose exposure
Sensitive populations (pregnant women, children)
Synergistic chemical interactions

In short, we are really just waiting for regulators to catch up with what scientists and researchers have known for decades regarding the harmful effects of paraben additives in personal care products.

Parabens in Your Toothpaste: What to Look For

Because oral products come into contact with highly permeable mucosa and are sometimes partially swallowed, exposure from toothpaste is particularly worth scrutinising. Check your toothpaste ingredient list for any of the following:

Methylparaben (E218) The most water-soluble paraben and most common in oral care. Most frequently found in toothpaste and mouthwash. Associated with estrogenic activity.²⁹

Propylparaben (E216) Found alongside methylparaben. Most commonly linked to breast cancer cell studies.³⁰

Ethylparaben (E214) Less common in toothpaste but present in some oral care products. Estrogenic properties documented in vitro.^31,32,33

Butylparaben Longer alkyl chains such as in butylparaben has been associated with greater endocrine disruption potency.^31,21,8 It is banned in EU products for children under three.³⁴

Benzylparaben Less common but worth noting. Documented estrogenic activity.³⁵

If you see any ingredient ending in "-paraben" on your toothpaste label, it is worth switching.

Safer Alternatives that Actually Work

The good news is there are effective preservatives that don't carry the same hormonal risk profile as common parabens. The cosmetics industry has been quietly reformulating for years in response to consumer pressure, and there are now well-studied, broadly safe alternatives available. Here are some safer alternatives to look for:

Sodium Benzoate Made from benzoic acid (present in fruits such as cranberries and plums) and sodium hydroxide, this is a common preservative in food products. Sodium benzoate is widely accepted in clean beauty formulations and approved by health authorities globally. It is effective against bacteria, yeast, and mold at low concentrations (typically ≤0.5%) and is considered low-risk for skin irritation, even on sensitive skin. It is also biodegradable and eco-friendly. It works best in formulations with a pH between 3 and 5, often combined with potassium sorbate for broader coverage.

Potassium Sorbate Approved by Australian Certified Organic (ACO) for use in certified organic products, potassium sorbate is a plant-derived preservative particularly effective against molds and fungi.³⁶ It is most often combined with other preservatives for full-spectrum protection. It is widely considered one of the safest preservatives available and is accepted in food-grade applications globally.

Sodium Anisate + Glyceryl Caprylate A newer pairing derived from anise and glycerin, this combination is effective against both bacteria and fungi, compatible with certified natural and organic standards, and well-tolerated by sensitive skin. Increasingly seen in premium clean beauty formulations.³⁷

Caprylyl Glycol + Phenethyl Alcohol This combination is approved in both the US and EU as a safe and effective paraben alternative. Both are alcohol-based, flush from the system easily without bioaccumulation, and are not associated with estrogenic activity. They are increasingly used in cleaner mainstream formulations.³⁸

Plant-Based Essential Oils and Extracts Ingredients like neem oil, tea tree extract, rosemary extract, and vitamin E (tocopherol) have documented antimicrobial properties backed by modern research. They work best in smaller-batch formulations and come with the added benefit of antioxidant and anti-inflammatory properties. Shelf life is shorter, typically one year: but this may also lend to fresher, less processed products.

‍Leucidal Liquid (Lactobacillus Ferment) Derived from fermented radish root (the same process as kimchi), leucidal liquid is a natural antimicrobial fully compatible with organic certification. It has a strong safety profile and is increasingly used in genuinely clean formulations as an alternative to both parabens and synthetic preservatives.³⁹

The Bottom Line

The paraben story is a familiar one in the history of chemical safety: widespread adoption driven by commercial convenience, followed by growing scientific alarm, followed by slow institutional response while consumers remain exposed. The difference today is that we have the evidence in peer-reviewed journals, in regulatory classifications across Europe, and in biomonitoring studies that find parabens in nearly every person tested. Luckily, we have alternatives.

Choosing paraben-free toothpaste, skincare, and personal care products is no longer a niche wellness decision. It is a reasoned response to a credible body of scientific concern. You don't have to wait for regulators to catch up. The burden of proof should not fall on consumers to prove a chemical is harmful. It should fall on manufacturers to prove safety before selling it to consumers, especially for products that contact your skin and mouth, and that your children use every day.

Check your labels. Look for alternatives. And remember: "we've always done it this way" is not science…it's inertia.