Contemporary studies document daily lip balm consumption of 1,270mg at the 95th percentile — 22 times the European Union's regulatory assumption of 0.057g — according to two peer-reviewed reviews that call for a wholesale re-think of how lip cosmetics are tested.

Published in Integrated Environmental Assessment and Management and commissioned by the Lip Service Alliance with University of Birmingham researchers, the reviews compare lip-product regulation across the UK, US, EU, Canada, China and South Korea. The verdict: ingestion assumptions rest on 2003–2005 surveys, the tissue models in use do not reflect lip biology, and categories that did not exist when those figures were drawn up now drive category growth.

What did the reviewers actually examine?

Researchers mapped how absorption through lip tissue and incidental ingestion are treated under cosmetic, food and pharmaceutical frameworks in six jurisdictions. They benchmarked lip products against the same dual exposure route used for oral-mucosal drug delivery and food-additive safety, then documented the gap left by treating lipsticks, glosses, balms, oils, masks and stains as ordinary topical cosmetics.

Why is lip tissue not just skin?

The lip vermilion carries only three to five protective cell layers, roughly one third the thickness of facial skin, with no oil glands, no hair follicles, and blood vessels lying close to the surface. That structure behaves more like oral mucosa than conventional skin. The reviews cite pharmaceutical data showing substantially higher permeability through oral mucosal tissue than skin for compounds including benzoic acid, caffeine and hydrocortisone.

None of the frameworks examined requires cosmetic ingredients destined for the lips to be tested on lip-specific or mucosal models. In the US, the 2022 Modernisation of Cosmetics Regulation Act (MoCRA) singled out products that regularly contact the mucous membrane of the eye for stricter oversight. It did not extend that recognition to products applied to the mouth.

Where do the ingestion numbers come from?

The EU and UK assume 0.057g per day at the 90th percentile for lipstick and lip salve, treating it as the full amount entering the body. The US references 87mg a day at the 95th percentile, but applies that ingestion figure for lead exposure only. Both derive from studies conducted between 2003 and 2005 and neither has been updated.

Canada, China and South Korea have never measured their own populations' lip-product use and rely on the European figures. China, the world's second-largest cosmetics market, is therefore assessed against a twenty-year-old survey of European consumers. Contemporary research indicates that 40% of US women aged 18 to 34 now use four or more lip-product types, routinely applied in sequence, often prompted by social-media tutorials.

How wide is the gap in practice?

The reviews cite studies that document lip balm consumption of 1,270mg per day at the 95th percentile. At that level, a heavy user of a single product accounts for roughly 463 grams a year through ingestion and absorption combined, equivalent to more than 90 standard 5g tubes.

Which ingredients sit in the regulatory blind spot?

Titanium dioxide remains permitted in lip cosmetics in the EU with no concentration limit, despite the regulator's 2022 ban on the same ingredient as a food additive over DNA-damage concerns. Eight or nine in ten conventional lipsticks and glosses contain a plastic; microplastics are slated to be banned in lip products by 2035 under EU rules, but only in the EU, and the restriction does not cover all plastic ingredients.

Separate studies referenced in the reviews have detected microplastics, trace metals and mineral oil hydrocarbons in lip products — substances subject to dietary exposure thresholds when formulated as food, but not when used in cosmetics consumed through the same ingestion route.

What do the authors recommend?

The reviews list seven actions, including:

• Developing lip-specific exposure assumptions that reflect real-world use patterns
• Commissioning population-specific exposure studies and embedding them in regulatory frameworks
• Mandating testing on human lip-specific tissue using validated non-animal methods
• Extending the food-grade ingredient principle — already applied by the cosmetics industry's own trade association to mineral oils in lip care — to all ingredient categories with established Acceptable Daily Intake values

Professor Iseult Lynch, Professor of Environmental Nanosciences at the University of Birmingham and a member of the Lip Service Alliance research team, said: "These critical reviews are an important first step in addressing a significant evidence gap in our understanding of how substances in lip products interact with the body. Through The Lip Service Alliance, we have brought together expertise from academia, industry and regulatory science to examine whether the assumptions used in current safety assessments accurately reflect the unique biology of the lips."

Laura DiGirolamo, lawyer and founder of the Lip Service Alliance and YOM Beauty, framed the food-flavour paradox: "Lip products are often made to taste like food and desserts, yet formulated with plastics. Eight or nine in ten conventional lipsticks and glosses contain a plastic."

She added: "There are so many ingredients restricted in food yet unrestricted in lip products we know are being ingested, and that is not even considering absorption through thin lip tissue. Nobody has been required to look at what years of that does, and an absence of proven harm is not the same as safety."

What changes for formulators, compliance and procurement?

For product developers, the reviews signal that the current regulatory baseline — a 0.057g daily lipstick figure drawn from a 2003 European survey — is unlikely to be the figure applied to next-generation dossiers. Updating exposure assumptions and lip-tissue models will increase pre-market workload and may bring reformulation pressure on flavourings, plastic-derived polymers and TiO2 in lip categories already under food-additive scrutiny.

For compliance teams in China, Canada or South Korea, the data raise the question of whether regulators will continue to outsource exposure assessment to the EU or commission domestic studies. Watch for any 2026–2027 re-evaluation by the European Chemicals Agency and the Scientific Committee on Consumer Safety, and for follow-up peer-reviewed work from the Lip Service Alliance on validated, non-animal lip-tissue models — the next concrete data points that will determine how quickly the recommendations move from paper to dossier.