Mineral Oils

WHAT ARE MINERAL OILS AND WAXES?

Mineral oils and waxes have been used in many industrial applications, including food, pharmaceutical and cosmetic products and medicine for over a hundred years.

They are prepared from naturally occurring crude petroleum oil, mainly consisting of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The latter could contain polycyclic aromatic hydrocarbons (PAH), which are potentially carcinogenic and genotoxic substances. This is why they are modified for some usage through a refining process.

The refining process of crude oil consists of various steps, including distillation, extraction, crystallization, and purification by acid treatment, hydrotreatment and/or solvent extraction. This removes impurities from crude oil and reduces PAH levels to trace amounts, to meet with international and European pharmacopoeia standards. In Europe, only highly refined mineral oils and waxes complying with the EU regulations are used in dermal cosmetics.

WHY AND HOW ARE MINERAL OILS AND WAXES USED IN COSMETIC PRODUCTS?

Mineral oils and waxes offer broad viscosity options, have protective and lubricating properties, are stable and well-tolerated. They are incorporated in many cosmetic products, including skin creams, ointments, lotions, sunscreens, lip care products and hair gels. Concentrations of mineral oils in cosmetics range from 1–99% depending on the product.

HOW ARE THEY CLASSIFIED AND WHAT IS THE REGULATION FOR USE?

In Europe, where regulations around cosmetics are stringent, only highly refined mineral oils and microcrystalline waxes of pharmaceutical grade, i.e. complying with the specifications of the European Union cosmetics regulation (1) and the European Pharmacopoeia, are used in cosmetic products for skin application. Accordingly, the full refining history has to be known and the starting material should not be carcinogenic (IP346 method) to prevent exposure to mineral oils with a potential concern to health.

Lip care products can have high oral exposure, and so the European trade association for the cosmetics and personal care industry (Cosmetics Europe), has advised manufacturers to only use food-grade mineral oils and waxes with an ADI (acceptable daily intake) value that meets the most stringent purity requirements on PAH (i.e. trace levels in the range of 0.0000001% w/w or 10 ppb) to ensure these are safe for use by consumers.(2)

WHERE DOES THE SAFETY CONCERN FOR MINERAL OILS COME FROM?

The European Food Safety Authority (EFSA)(3) and the French Agency for Food, Environmental and Occupational Health and Safety (ANSES)(4) identified exposure to MOSH and MOAH via food and food packaging as being of potential concern for human health. In view of this concern and possible oral exposure via other sources, several European consumer organisations then called into question the safety profile of mineral oils in lip balms.(5)

Following testing of a range of lip balms representing the main national and international brands, the European Consumer Organisation (Bureau Européen des Unions de Consommateurs, or BEUC) reported that daily application of lip care products contributes to the overall consumer exposure to MOSH and POSH (POSH are polyolefin oligomeric saturated hydrocarbons, synthetic hydrocarbons which are similar to MOSH without having impurities such as PAH). They invited the European Commission to establish health-based guidance values (ADI or tolerable dose intake, TDI) for mineral oils in lip care products, in particular MOSH and MOAH.(5) By association and likely because of confusion, this warning led the lay public and the media to feed the narrative of potential harm caused by mineral oils in all cosmetic products.

WHEN MINERAL OILS ARE USED ON SKIN, THEY ARE NOT ABSORBED AND HAVE NO CUTANEAOUS SIDE EFFECTS

As they are highly lipophilic, mineral oils do not penetrate the skin and are therefore not systemically bioavailable by the body and are mostly restricted to the stratum corneum of the skin.(6)

No significant changes in the skin and no effects on any internal organ systems have been reported as a result of subchronic topical application of refined white mineral oils in animals. (7)

In humans, patch-test studies using medicinal white oils or waxes in almost 80,000 patients did not report any instances of skin sensitisation, with just a few sporadic cases of mild erythema reported after application on even damaged skin.(8-11) These cases were not considered to be related to cosmetic allergy. White petrolatum and waxes are hence considered non-sensitisers and rarely allergenic, with the sensitising components likely to be PAH.(9, 12)

Additional human studies have reported that moisturisers containing 10% of mineral oil slightly reduce the minimal erythemal dose (MED) of UVB irradiation on the skin by 5–16%, suggesting that the skin becomes slightly more sensitive to UVB radiation. However this sensitivity effect is similar to that seen with seasonal changes, where there is an average MED increase of 14% between January and April.(13)

Therefore, current data in humans suggests that there is no evidence of mineral oils having effects via the cutaneous route.(8, 13)

WHEN MINERAL OILS ARE USED IN LIP CARE PRODUCTS, THEY ARE SAFE

Oral intake is limited:

• Consumers ingest approximately 20 g/year of lip balm, through daily use; this is the equivalent of 4 typical lip balms per year.(5)
• MOSH exposure can be estimated up to 0.7 mg/kg/day for a 60-kg person, representing less than 10% of the ADI value set for the highly refined mineral oils used in these products.(8)
• Therefore there is a moderate oral intake of hydrocarbons through lip care products; however this does not represent a significant safety risk for the consumer.(8)

There is no oral toxicity of mineral oils in the context of cosmetic products:

• Acute oral toxicity is not relevant in the context of exposure via cosmetic products, and besides, MOSH and MOAH have low acute oral toxicity.(3, 8)
• Regarding chronic exposure, it is important to note that animal studies did not show any indication of granuloma formation in the liver for medium and high viscosity mineral oils and microcrystalline waxes, which are the qualities recommended by the Cosmetics Europe for lip care products. Additionally, high doses used in animal studies are not relevant for mineral oils used in cosmetic ingredients.
• The incidence of lipogranulomas in human tissues is low, linked to the accumulation of MOSH mainly by food intake, and are considered to be non-adverse effects.(3-14)

Based on these data, toxic risks are not expected from the oral uptake of MOSH through lip care products that comply with Cosmetics Europe recommendations.(2, 8)

MINERAL OILS ARE NOT ASSOCIATED WITH CARCINOGENIC, MUTAGENIC OR REPROTOXIC EFFECTS

Carcinogenicity and mutagenicity of mineral oils are caused mainly by some MOAH, including PAH. Cumulative evidence demonstrate that highly refined white mineral oils with very low PAH content are neither carcinogenic nor mutagenic. Food-grade mineral oils and waxes used in lip care products do not carry any carcinogenic potential, via either the cutaneous or oral routes of administration.

There is no evidence of reproductive toxicity via oral or cutaneous routes in experimental animal studies with food-grade mineral oils. The effect on reproduction cannot be fully excluded for MOAH when using non-food grade mineral oils (non-highly refined mineral oils which are not used in cosmetics).(3)

MINERAL OILS DO NOT ALTER IMMUNE FUNCTION OR CAUSE AUTOIMMUNITY

To date, there is no evidence to suggest that oral or epidermal exposure to mineral oils in animals or humans leads to altered immune function or autoimmunity. Where presumptive associations have been made, high levels of exposure to mineral oils (of all types) mainly occurred via inhalation or the intradermal route.

Actual levels of exposure to mineral oils (non-food grade and by routes other than cutaneous) have not usually been measured in these studies, and other genetic and environmental factors such as infection, vaccination, and tobacco consumption may also be involved in the development of these autoimmune reactions.(14)

The safety profile of highly refined mineral oils in cosmetic products has also been recently assessed by the German Federal Institute for Risk Assessment (BfR).(8) The German BfR global risk assessment was based on a systematic literature review on mineral oils, and concluded that there is no health risk for the consumer from the cutaneous application of cosmetic products containing pharmaceutical- and food-grade mineral oils. Moreover, health risks are not to be expected from the oral intake of highly refined mineral oils, if lip care products comply with the recommendation of Cosmetics Europe.

CONCLUSION: THE SCIENTIFIC DATA SHOWS THAT MINERAL OILS AND WAXES ARE SAFE FOR COSMETIC USE

Highly refined mineral oils and waxes used in cosmetic products can be considered as safe in human for:

• Skin application: no health risk was identified in humans with respect to cutaneous toxicity, reproductive toxicity, and the development of autoimmune response and disease.
• Oral exposure: no risk of carcinogenicity, mutagenicity, reproductive toxicity or autoimmunity with mineral oils of pharmaceutical and food grades.
• For lip care products: no significant health risk was found when complying with the recommendation of Cosmetics Europe, i.e. highly refined mineral oils and a daily ingestion below the ADI value of 12 mg/kg/day.