The ingredient encyclopedia

Butylphenyl MethylpropionalAVOID

Banned outright from all EU and UK cosmetics since March 2022 as a presumed reproductive toxicant (CMR 1B), still fully legal in the United States.

Hydrofluorocarbon 152aCAUTION

Banned from personal-care aerosols in the EU, but for environmental (greenhouse-gas) reasons, not consumer-safety ones. At normal use the direct health risk is low; we won’t pretend otherwise.

Fragrance (Parfum)CAUTION

Not a hazard in itself, but a legal black box. “Fragrance” can shield ingredients (including EU-banned ones) that you are never told are there.

LimoneneCAUTION

Harmless fresh, but it oxidizes in air and on skin into potent contact allergens. Real, measurable sensitization; not a cancer scare.

LinaloolCAUTION

Same story as limonene: weak on its own, a real sensitizer once oxidized. Common cause of fragrance contact allergy.

CoumarinCAUTION

A recognized fragrance allergen present in most deodorants. Sensitization is real but bounded; no credible cancer signal at cosmetic exposure.

CitralCAUTION

Among the most frequently reported fragrance allergens; a sensitizer, not a systemic toxin.

CitronellolCAUTION

Recognized fragrance contact allergen (EU H317); cross-reacts with geraniol.

GeraniolCAUTION

One of the most frequently reported fragrance contact allergens in EU clinics.

Alcohol Denat.ACTUALLY FINE

Fearmongered as “toxic alcohol,” but at cosmetic use it is well-tolerated and evaporates within seconds. We clear it.

Zinc NeodecanoateACTUALLY FINE

Reviewed safe at cosmetic use levels. The only honest caveat is the aerosol particulate it shares with everything else in the can.

Aluminum Zirconium Tetrachlorohydrex GlyACTUALLY FINE

The most fearmongered ingredient in your bathroom, and the EU's own scientists found no reliable link to breast cancer or Alzheimer's. We clear it.

CyclopentasiloxaneCAUTION

Being phased out across the EU by 2027, but for the planet, not your body. The SCCS judged it safe for human health; the restriction is environmental.

BHTCAUTION

A synthetic antioxidant the EU flagged for possible endocrine effects and the UK restricted in 2024, safe at low levels, watched closely abroad, unrestricted here.

Propylene GlycolACTUALLY FINE

Fine on its own, the one honest caveat is that it's a penetration enhancer, so it helps everything else in the formula sink in deeper.

PPG-14 Butyl EtherACTUALLY FINE

An emollient carrier with a clean CIR safety review and no EU or US restriction. Boring, and that's the point, not everything on a label is a villain.

Pyrithione ZincAVOID

Head & Shoulders cannot legally be sold as a cosmetic anywhere in the EU, its active ingredient was banned in 2022 as a presumed reproductive toxicant. It's still the #1 dandruff shampoo here.

Sodium Laureth SulfateCAUTION

The sulfate itself just cleans, the real issue is 1,4-dioxane, a probable carcinogen created when it's made, that never appears on the label.

Sodium Lauryl SulfateCAUTION

It does NOT cause cancer, that viral claim is a myth. What it actually does is strip and irritate skin, which matters if yours is reactive.

Cocamidopropyl BetaineCAUTION

Named Allergen of the Year in 2004, but the molecule isn't the culprit. A manufacturing impurity (DMAPA) is what sensitizes people.

MethylisothiazolinoneCAUTION

A preservative the EU banned from all leave-on products after it triggered an allergy epidemic across Europe. Capped hard in rinse-off there; uncapped here.

HomosalateAVOID

The EU's own science panel found it unsafe above 0.5%, every sunscreen here uses it at 9–15%, up to 30× that level. The FDA still allows it.

OctocryleneCAUTION

Degrades inside the bottle into benzophenone, a carcinogen with zero allowed level in food and no safe harbor under Prop 65. The longer it sits, the more forms.

OxybenzoneAVOID

Banned in Hawaii and Key West, absorbs into your blood at 250× the FDA's own safety threshold. Good news: the sunscreens we tore down already dropped it, many others didn't.

AvobenzoneACTUALLY FINE

The workhorse UVA filter. It absorbs into skin like the others, but carries no specific harm finding, and it's what's actually protecting you from deep UVA.

OctisalateACTUALLY FINE

A mild, low-scrutiny UVB filter that also stabilizes avobenzone. Nothing in the evidence flags it. Cleared.

Sodium Coco-SulfateACTUALLY FINE

The ingredient is fine. The problem is the front of the bottle: Native says 'Sulfate Free' while this sulfate sits second on the label. The lie is the story, not the chemistry.

Sodium Lauroyl IsethionateACTUALLY FINE

A genuinely mild, sulfate-free cleanser with a clean safety record. One of the good ones.

Iodopropynyl ButylcarbamateCAUTION

An iodine-releasing preservative the EU restricts by product type and flags for thyroid concern, pregnant women and under-3s are told to avoid it abroad. No such limit here.

PhenoxyethanolCAUTION

The default paraben replacement, cleared by the EU at up to 1%, but France moved to keep it off babies' skin. Fine for most; watch it around infants.

Cocamide MEACAUTION

Not the same as Cocamide DEA (a listed carcinogen), but it can carry trace DEA from manufacturing. The distinction is real, and worth knowing.

Tetrasodium EDTAACTUALLY FINE

A chelator that keeps formulas stable. It barely penetrates skin and carries no hazard finding. Cleared, though it does nudge other ingredients in slightly.

MethylparabenACTUALLY FINE

The paraben the breast-cancer scare was built on, and that 2004 study found parabens present, never proven they caused anything. Short-chain parabens like this are well-tolerated. Cleared.

ButylparabenCAUTION

The paraben that actually earns scrutiny, the EU caps it at 0.14% and bans it from baby products over weak estrogen activity. Not all parabens are equal.

Quaternium-15AVOID

Releases formaldehyde, a known human carcinogen, right at your eye. Already banned in Washington State, with a US federal ban proposed for 2027. The EU forces a warning label; here it's silent.

Diethyl PhthalateCAUTION

An endocrine-disrupting plasticizer hidden inside the word 'Fragrance', found at up to 40,000 ppm in body sprays by the FDA's own survey, disclosed to you nowhere.

OctinoxateCAUTION

An estrogen-active UV filter banned from Hawaii's reefs, and oddly sprayed onto skin and inhaled in a fragrance mist that makes no sunscreen claim at all.

Benzyl AlcoholCAUTION

A dual-use preservative and fragrance allergen, the EU makes brands name it on the label; here it can hide inside 'Fragrance.'

Hexyl CinnamalCAUTION

A jasmine-scented fragrance allergen on the EU's named-disclosure list, a documented sensitizer that US labels can bury under 'Fragrance.'

Alpha-Isomethyl IononeCAUTION

A violet-scented fragrance allergen the EU requires named on-label. Real sensitizer, routinely undisclosed here.

Benzyl SalicylateCAUTION

A fragrance allergen and weak UV absorber on the EU disclosure list, flagged abroad, hidden in 'Fragrance' here.

Titanium DioxideAVOID

Banned as a food additive across the EU in 2022 over genotoxicity its own scientists couldn’t rule out, and it’s a pure whitening pigment you partly swallow with every brush. Still legal here.

Sodium Fluoride / Stannous Fluoride / Sodium MonofluorophosphateCAUTION

Not the conspiracy some claim, topical fluoride genuinely prevents cavities. The real caveat is dose: small children swallow a third of the paste, which is why there’s a warning on the tube. Spit, don’t swallow.

TriclosanAVOID

An endocrine-disrupting antibacterial the FDA banned from soaps and the EU restricted, and the active in Colgate Total until they quietly reformulated it out around 2019. Worth knowing what was in the tube you trusted for years.

Sodium SaccharinACTUALLY FINE

The artificial sweetener at the center of a 1970s cancer panic, and delisted as a carcinogen decades ago when the rat-bladder mechanism turned out not to apply to humans. Cleared.

Hydrated SilicaACTUALLY FINE

The abrasive that scrubs your teeth, essentially refined sand. Inert, not absorbed, no hazard finding. Cleared.

Sodium BorateCAUTION

The EU classifies it a reproductive toxicant and restricts it in consumer products, yet it’s in Tide and Gain here. The honest part: that classification comes from high doses; what rinses out of your laundry is low. The story is the regulatory gap, not poison in your wash.

1,4-DioxaneCAUTION

A probable carcinogen that’s never on the label because it’s a manufacturing contaminant, not an ingredient, found in these detergents above New York’s legal limit before 2024 reformulation. The only US rule that touches it is one state’s.

BenzisothiazolinoneCAUTION

A preservative the EU classifies a skin sensitizer and restricts, printed by name on US Gain and Febreze labels, with no US limit. A genuine allergen, disclosed here only because the EU forced the science.

Optical BrightenersCAUTION

Chemicals that don’t clean anything, they coat your clothes to trick your eye into seeing ‘whiter,’ stay on the fabric against your skin, and are persistent in waterways. A cosmetic illusion you wear all day.

PetrolatumCAUTION

Refined cosmetic-grade petroleum jelly is genuinely low-risk. The catch is that the US never makes anyone prove it is the refined grade, the EU prohibits it unless they do, and the less-refined yellow grades can carry PAH carcinogens. In a US product you can't verify which one you are getting.

DMDM HydantoinCAUTION

A preservative that works by slowly releasing formaldehyde, a known human carcinogen. The EU forces a ‘releases formaldehyde’ warning on the label; the US requires nothing. Lower exposure than a leave-on near the eye, but you’re rubbing it over your whole body daily.

Paraffin WaxCAUTION

A petroleum wax whose combustion releases soot and trace VOCs. An occasional candle in a ventilated room is low-risk; a plug-in or candle burning continuously in a closed room is where the emissions add up. Ventilation is the whole game.

PTFECAUTION

Stable and inert at normal cooking heat, the real risks are specific: an empty pan overheated past 500°F releases fumes that sicken people (and kill birds), and a scratched coating sheds particles. Don’t preheat empty, don’t use metal utensils, replace it when it’s scratched.

PFOAAVOID

Upgraded to a Group 1 human carcinogen in 2023 and phased out of US nonstick production around 2015, but it’s a ‘forever chemical’ that’s still in older pans, your blood, and the water. If your nonstick pan predates 2015, it’s the one to retire.

PFAS ReplacementsAVOID

The ‘safer’ chemicals that replaced PFOA, and the EPA links them to the same liver, kidney, immune and developmental harms. A textbook regrettable substitution. The EU is moving to restrict the entire PFAS class; the US has a patchwork of state cookware bans and no federal rule.

Lead & Cadmium in Cookware GlazesAVOID

Cheap imported glazed and aluminum-alloy cookware can leach lead and cadmium, both potent toxic metals, straight into your food, and the FDA issued fresh enforcement alerts on leaded imports in 2025. There is no safe level of lead. Avoid unbranded imported metal/glazed cookware.

Aluminum (bare / anodized cookware)CAUTION

Bare aluminum leaches small amounts into acidic foods like tomato sauce; the amounts are low and the dietary-aluminum-causes-Alzheimer’s link is not supported. Anodized aluminum is sealed and a non-issue. A minor point, not a panic.

Ceramic Nonstick CoatingACTUALLY FINE

The PFAS-free nonstick alternative, a silica-based coating with no forever chemicals. The honest catch is durability, not toxicity: it wears out faster than PTFE. Pair it with cast iron or stainless and you’ve sidestepped the whole cookware problem.

HexamethylindanopyranCAUTION

Bioaccumulates in human tissue and is now EU label-restricted (2023/1545), with a Repr. 1B reproductive-toxicity classification working through the EU system as of 2026. Heading toward restriction, not yet banned.

Acetyl Hexamethyl TetralinCAUTION

A persistent, bioaccumulative musk the EU's scientific committee flagged as having insufficient safety data, repeatedly detected in human body-burden studies. Real concern, incomplete evidence.

Hydroxyisohexyl 3-Cyclohexene CarboxaldehydeAVOID

Banned from all EU cosmetics (Annex II, Regulation 2017/1410) as one of the highest-causing fragrance contact allergens. Still fully legal in US products, where it can hide inside “Fragrance.”

Evernia Prunastri ExtractCAUTION

An EU Annex III declarable allergen whose two most sensitising constituents (atranol, chloroatranol) were banned outright. “Natural” here does not mean gentle, classic perfumes are the high-risk category.

EugenolCAUTION

An established EU-declarable contact allergen, positive in over half of fragrance-allergic patients tested. The mechanism is skin sensitisation, not systemic toxicity, so this is a measured caution, not a scare.

IsoeugenolCAUTION

The strictest-controlled of the established fragrance allergens: an EU concentration cap of 0.02%, not just a labelling rule, plus the highest patch-test positivity of the group. A strong caution.

HydroxycitronellalCAUTION

An EU-declarable allergen important enough to sit in Fragrance Mix I, the standard clinical patch-test panel for diagnosing fragrance allergy. Skin sensitiser, not a systemic toxin.

FarnesolCAUTION

One of the original EU-declarable fragrance allergens. A genuine sensitiser for some, but among the milder of this group, the honest read is label-awareness, not alarm.

Dioxins & FuransCAUTION

TCDD is a genuine IARC Group 1 carcinogen, and chlorine bleaching of tampon fiber once produced it. The honest catch: the industry shifted to chlorine-free bleaching in the 1990s and product levels are now trace, far below dietary dioxin. Real chemistry, small product-level dose.

GlyphosateCAUTION

The single most contested classification in this set: IARC calls it a probable human carcinogen (Group 2A); the EU, EPA, and WHO/FAO did not classify it as carcinogenic. Residue has been measured on non-organic cotton tampons and gauze at low ppb. Both camps are real, we name both.

StyreneCAUTION

IARC upgraded styrene to probable human carcinogen (Group 2A) in 2018, and a peer-reviewed 2020 survey found it in menstrual pads, with scented pads carrying about ten times the aromatic VOCs of unscented. Present at trace levels, so a calibrated caution.

ChloroformCAUTION

IARC lists chloroform as possibly carcinogenic (Group 2B) on a likely non-genotoxic, threshold mechanism. Detected in a majority of feminine hygiene products in a 2020 survey, at trace levels, with organic and unscented options lower. A measured caution, not an alarm.

Rayon / ViscoseCAUTION

Two real but bounded concerns: it carries the dioxin-bleaching history, and very high-absorbency synthetic-fiber tampons drove the 1980 toxic shock epidemic. Today's viscose is far safer, and TSS is rare and tied to absorbency and wear time, not the fiber alone.

Polyethylene & Polypropylene (Pad Plastics)ACTUALLY FINE

On acute health these are inert polymers with low toxicity, and the 'plastic in your pad is poisoning you' framing overshoots. The genuine costs are environmental (huge lifetime waste) and comfort (heat and moisture), with microplastic shedding an emerging, not-yet-proven, question. We clear the acute-health scare and name the real cost.

Lead, Arsenic & Cadmium (in Tampons)CAUTION

A 2024 peer-reviewed study detected lead, arsenic, and cadmium in 100% of 30 tampon brands tested, organic and conventional alike, and there are no regulatory limits for metals in menstrual products. The detection is certain; whether the metals actually leach into tissue is the open question regulators began testing in 2024.

TalcAVOID

IARC reclassified talc as probably carcinogenic to humans (Group 2A) in 2024; the EU classified it CMR 1B and is set to ban it from cosmetics by 2027; and asbestos-contaminated talc is a confirmed Group 1 carcinogen. J&J pulled its talc baby powder under 67,000+ lawsuits. Restricted/banned in the EU while still legal here is the textbook AVOID.

Quaternary Ammonium Compounds (Quats)CAUTION

The strongest evidence is real: quats are a documented cause of occupational asthma and respiratory sensitization in cleaning and healthcare workers. Animal reproductive signals and an antimicrobial-resistance role are plausible but not settled. EPA calls them non-carcinogenic. A genuine, dose-and-route caution.

Glycol Ethers (incl. 2-Butoxyethanol)CAUTION

The main effect is hematotoxicity (red-cell damage) via a metabolite, documented mostly in animals and in high-dose human poisonings, not in routine spritzing. Not classified as a carcinogen. Inhalation in poorly ventilated use is the route that matters. A measured caution.

AmmoniaCAUTION

At household concentrations with ventilation, ammonia is a transient irritant, not a chronic hazard. The real danger is specific and severe: mixed with bleach it makes toxic chloramine gas. The caution is about the mixing, not the molecule.

Sodium Hypochlorite (Chlorine Bleach)ACTUALLY FINE

Bleach gets treated as a chronic toxin and it isn't one. At household concentrations it is an effective, well-understood disinfectant that degrades to salt and water, with no established chronic-cancer signal. We clear it. The real risks are acute and entirely about handling: fumes in a closed room, and the dangerous gases it forms when mixed.

Dimethicone (Silicone)ACTUALLY FINE

Repeatedly cleared by CIR: it does not penetrate skin, is not a carcinogen or mutagen, and has very low toxicity. The two genuine issues are buildup (a hair-feel and wash-frequency cycle, not a health risk) and the environmental restriction on a different molecule, volatile D5. We clear it and name the real nuance.

Cationic Conditioning Agents (Conditioner Quats)ACTUALLY FINE

CIR and the EU's SCCS have cleared these at rinse-off conditioner concentrations, with mild irritation only at high levels. Critically, these are not the sprayed disinfectant quats linked to occupational asthma, different chain length, concentration, and route. Treating them as the same is a category error we avoid.