Nanomaterials in Cosmetics — Genuine Hazard or Precise Solution?

The word „nano” on a cosmetic label triggers extreme reactions — from fascination with the technology to fear of the unknown. Yet nanomaterials in cosmetic products are not a modern fad but a solution that has been used in UV sunscreens since the 1990s. So let’s set the emotions aside and look at the data.

Definition and scale — what does „nano” actually mean?

According to European Commission Recommendation 2011/696/EU, a nanomaterial is a material containing particles of which at least 50% in the number size distribution have one or more dimensions in the range of 1–100 nm. For context: a human hair is roughly 80,000 nm in diameter, a red blood cell about 7,000 nm, and a nano-TiO2 particle in a sunscreen typically 20–30 nm.

Why does size matter? Reducing a particle to the nanometre scale changes its optical, catalytic and surface properties. In the case of TiO2 and ZnO, this means better UV protection with less white cast on the skin. Conventional (micro) TiO2 leaves a visible white film — nano-TiO2 is optically transparent, which improves the cosmetic feel and therefore compliance (people are more willing to use a cream that doesn’t look like a white mask). Check the details in our ingredient encyclopaedia.

Nano-TiO2 — a UV filter that doesn’t penetrate the skin

Titanium dioxide in nano form (nano-TiO2) is a physical UV filter — it reflects and scatters UVB and, in part, UVA radiation. The SCCS has assessed its safety on numerous occasions, and the key conclusions are consistent.

The 2013 SCCS opinion (SCCS/1516/13, revised in 2014) confirmed that coated nano-TiO2 at concentrations up to 25% is safe for dermal applications. The most important point: nano-TiO2 does not penetrate intact skin. In vivo studies using tape-stripping (Sadrieh et al., 2010, Toxicological Sciences) and confocal microscopy (Filipe et al., 2009, Skin Pharmacology and Physiology) clearly demonstrated that the particles remain in the stratum corneum and do not reach the living cells of the epidermis.

Why is the skin barrier so effective? The stratum corneum consists of 15–20 layers of flattened, keratinised corneocytes surrounded by a lipid matrix with a lamellar structure. A particle 20–30 nm in diameter is too large to pass through the intercellular spaces of this structure (around 6–8 nm wide). Sunburned, atopic or mechanically damaged skin is a different matter — but the SCCS assesses safety on intact skin as the standard scenario.

Nano-ZnO — effective UVA protection

Zinc oxide in nano form (nano-ZnO) provides broad-spectrum protection — it is especially effective in the UVA range (320–400 nm), where TiO2 is weaker. In its 2012 opinion (SCCS/1489/12), the SCCS considered nano-ZnO safe at concentrations up to 25% in sunscreen products, with the same caveat: no penetration of intact skin.

An interesting aspect: zinc is an essential trace element for the body (daily requirement 8–11 mg). Even if minimal amounts of Zn²⁺ ions released from nano-ZnO were to reach the dermis, they would represent a fraction of the body’s physiological zinc turnover. This doesn’t change the fact that solid nano-ZnO particles don’t penetrate — but it shows why the scenario of “contaminating” the body is unrealistic.

The [nano] label — regulated since 2013

Since July 2013, under Article 19 of Regulation 1223/2009, all ingredients in nanomaterial form must be marked on the label with the word [nano] after the INCI name. For example: „Titanium Dioxide [nano]”, „Zinc Oxide [nano]”.

Additional regulatory requirements:

• Notification 6 months before market launch — the manufacturer must notify the European Commission via the CPNP portal of its intention to place a cosmetic containing a nanomaterial on the market (Article 16).
• Catalogue of nanomaterials — the Commission maintains a public database of notified cosmetic nanomaterials, updated every six months.
• Presumption of hazard — if the SCCS raises safety concerns about a notified nanomaterial, the Commission may ban its use within 6 months of notification.

It’s worth knowing how to read a label bearing the [nano] designation — our guide to the INCI list explains all the ingredient naming conventions.

Inhalation — the only genuine concern

If nano-TiO2 and nano-ZnO don’t penetrate the skin, where does the potential risk lie? The answer: in the respiratory tract. The lungs, unlike the skin, have no stratum corneum — the alveoli have a wall just one cell thick, designed for gas exchange rather than as a barrier against solid particles.

In its 2013 opinion, the SCCS stated unambiguously: nano-TiO2 cannot be considered safe in products that may lead to inhalation — specifically aerosols (UV-filter sprays) and loose powders. Rodent studies (Bermudez et al., 2004, Toxicological Sciences) showed that chronic inhalation of ultrafine TiO2 particles (21 nm) at a concentration of 10 mg/m³ led to chronic lung inflammation, fibrosis and tumours in rats (but not in mice and hamsters — suggesting a species-specific mechanism linked to lung overloading in rats).

In practice, this means that creams and lotions containing nano-TiO2/ZnO are safe, but aerosols with these ingredients raise legitimate concerns. That is why many European brands offer mineral filters exclusively in cream form, avoiding spray formulations.

Other nanomaterials in cosmetics

Beyond TiO2 and ZnO, cosmetics may also contain other substances in nano form:

• Nano-silver — used as a preservative in a small number of products. The SCCS has not issued a positive safety opinion on colloidal nano-silver in cosmetics.
• Carbon black [nano] — a pigment in mascaras and eyeliners. In its 2015 opinion, the SCCS restricted its use, excluding applications that may lead to inhalation.
• Nano-hydroxyapatite — in toothpastes as an alternative to fluoride. Its regulatory status in the EU is currently under discussion.

Want to check whether your sunscreen contains nanomaterials? Enter its ingredient list into the PurScore analyser — we’ll show you which ingredients are in nano form and what the SCCS says about them.

Summary — nanomaterials are no black magic

Nanomaterials in cosmetics — in particular nano-TiO2 and nano-ZnO in sunscreens — rest on a solid body of evidence confirming their safety for dermal use. They don’t penetrate intact skin, they provide effective UV protection and they have a better cosmetic profile than the micro forms. Legitimate concerns apply only to inhalable formulations — and that is precisely what the regulation focuses on.

The [nano] designation on a label is not a warning — it’s information that enables an informed choice. Make use of it.

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