Ingredient Safety Guide

How to read an ingredient list

Every cosmetic and personal care product lists ingredients in descending concentration order (INCI system). The first 5-6 ingredients make up 80-90% of the product. Ingredients below 1% concentration can appear in any order — this is where preservatives, fragrance, and active ingredients at low doses appear.

Rule of thumb: If a concerning ingredient is in the first 5, it’s a significant part of the product. If it’s near the bottom, the concentration is likely negligible.

The evidence hierarchy

Not all “toxic ingredient” claims carry equal weight:

Evidence level	What it means	How to respond
Banned by EU/FDA	Regulatory bodies reviewed evidence and prohibited it	Avoid. Non-negotiable.
EU-restricted	Allowed at limited concentrations	Check concentration. Product may be fine.
Peer-reviewed concern	Published studies show risk at certain exposures	Context matters — dose, route, duration.
EWG high score	Environmental Working Group flagged it	Research independently. EWG uses conservative methodology.
Influencer claim	Someone on TikTok said it’s toxic	Verify with primary sources before acting.

Preservatives: the necessary trade-off

Every water-containing product needs a preservative or it grows bacteria within days. The question is never “preservative vs. no preservative” — it’s “which preservative system is acceptable?”

Parabens (methylparaben, propylparaben, butylparaben): The most studied preservatives in cosmetics. Methylparaben at 0.4% or less is considered safe by the EU SCCS. Propylparaben and butylparaben have more concern — EU restricts them in children’s products. The “paraben-free” movement often replaces parabens with less-studied alternatives.

Phenoxyethanol: The most common paraben replacement. EU-approved up to 1%. Generally well-tolerated. Can irritate very sensitive skin at high concentrations.

Formaldehyde releasers (DMDM Hydantoin, Quaternium-15, Imidazolidinyl Urea): These slowly release formaldehyde as a preservative. Formaldehyde is a known sensitizer and carcinogen at high exposure. The cosmetic concentrations are low, but accumulation across multiple products is the concern. If you use 10 products daily and 4 contain formaldehyde releasers, total exposure adds up.

Surfactants: the cleaning agents

SLS (Sodium Lauryl Sulfate): Effective cleanser. Known skin irritant — used as the standard irritant in dermatological patch testing. Fine in rinse-off products (shampoo, body wash) at normal concentrations. Avoid in leave-on products or if you have eczema/sensitive skin.

SLES (Sodium Laureth Sulfate): Milder than SLS. The ethoxylation process can leave trace 1,4-dioxane (a carcinogen), but reputable manufacturers test and ensure levels are negligible. Not the same as SLS despite similar names.

Sulfate-free alternatives (Cocamidopropyl Betaine, Sodium Cocoyl Isethionate): Gentler surfactants. Less foam, same cleaning power. Better for sensitive and dry skin.

Fragrance: the transparency problem

“Fragrance” or “Parfum” on a label is a legal umbrella covering potentially thousands of individual chemicals. Companies aren’t required to disclose the specific fragrance compounds because they’re considered trade secrets.

This is the single biggest transparency gap in cosmetics. A product with 30 listed ingredients might actually contain 60+ compounds once you unpack the fragrance.

What to do:

• “Fragrance-free” means no fragrance compounds (best for sensitive skin)
• “Unscented” means fragrance compounds are used to mask other smells (not the same as fragrance-free)
• Products scented with named essential oils (e.g. “Lavandula Angustifolia Oil”) are more transparent than “Fragrance”

The dose makes the poison

Paracelsus said it in 1538 and it’s still the foundation of toxicology: everything is toxic at some dose, and everything is safe at some dose. Water is toxic at 6 liters. Arsenic occurs naturally in rice. The question is always: at the concentration in this product, applied to skin, is the exposure meaningful?

Most “toxic ingredient” fears ignore concentration. A ingredient at 0.01% in a rinse-off product that contacts skin for 30 seconds is fundamentally different from the same ingredient at 5% in a leave-on product applied twice daily.