Nano-whaticle? What’s in your Dad’s personal care products.

Nanoparticles — particles 1 to 100 nanometres across — appear in many conventional personal care products to control color, transparency, and texture. Health researchers have raised concerns about skin penetration and long-term tissue accumulation, which is why checking a product's ingredients matters especially for teens who use them every day. Here's what nanoparticles are, how they end up in personal care products, and what the research currently shows.

What is a nanoparticle? (Smaller than it sounds)

A nanoparticle is a particle of matter between 1 and 100 nanometres in diameter — thousands of times smaller than the width of a human hair. At this scale, materials behave differently than they do at normal size. Titanium dioxide and zinc oxide, for example, are both naturally occurring minerals used safely in personal care at standard particle sizes — but when engineered to nano scale, the same compounds can behave differently, penetrating surfaces they couldn't otherwise reach and raising different biological questions. Nanoparticles are deliberately used in personal care products because their tiny size enables properties — finer textures, increased transparency, stronger color payoff — that the same ingredients at standard size can't deliver. It's the engineered size reduction itself that is the design choice, and the engineered size itself that raises the concern.

How nanoparticles are used in conventional personal care

Nano-scale particles appear in conventional personal care for specific cosmetic effects: titanium dioxide and zinc oxide in sunscreens are frequently nano-sized to eliminate the white cast that standard-size mineral sunscreen produces. Nano silver is used as an antimicrobial preservative in some formulas. Nano-scale colorants appear in shampoos and body washes to improve color stability. Carbon-based nanoparticles are used as UV filters in some products. What these applications share is a deliberate choice to reduce ingredient particles to a scale where they interact with surfaces — including skin — differently than the standard-size version. The benefits are primarily cosmetic and aesthetic. The tradeoffs are under ongoing scientific scrutiny, and many researchers argue that ingredient identity alone is insufficient to assess safety when the particle size has been fundamentally altered.

What the research says about nanoparticles and skin

Research on nanoparticle absorption through skin has produced mixed findings, and the science is still developing. Some studies have demonstrated that nano-sized titanium dioxide particles can penetrate skin more deeply than standard-size versions, particularly through hair follicles, which cover a significant portion of skin surface. The European Commission's Scientific Committee on Consumer Safety (SCCS) has conducted repeated reviews of nano-ingredients in cosmetics and concluded that safety assessments must be done case-by-case — that different nano-forms of the same ingredient behave differently, and that clearance for one nano-form does not cover others. Concerns about systemic absorption, tissue accumulation over years of daily use, and potential cellular effects remain active research questions. The practical takeaway for parents: choosing personal care products built on standard-scale plant and mineral ingredients sidesteps the open questions entirely, without sacrificing effectiveness.

Where nanoparticles go after the shower

The nanoparticles that aren't absorbed by skin don't disappear when rinsed off. They pass through household drains, through wastewater treatment systems that were not designed to filter particles at this scale, and into rivers and coastal waterways. Environmental research has detected nano titanium dioxide and nano silver in aquatic sediments and has documented effects on aquatic organisms at concentrations found in real waterways. Because nano-scale particles move through standard filtration that would capture larger particles of the same material, their environmental persistence is distinct from that of conventional synthetic chemicals. The environmental load compounds across millions of daily personal care uses, which makes individual product choices meaningfully relevant at scale.

What natural personal care products use instead

Natural personal care products that avoid engineered nanoparticles achieve their effects through plant-derived and standard-scale mineral ingredients that work through surface-level chemistry rather than nano-scale penetration. Prep U's deodorant line uses non-nano zinc oxide and magnesium as part of its Active Mineral & Botanical Blend — standard-particle mineral ingredients that neutralize odor-causing bacteria on the skin's surface. Plant-based cleansers in Prep U's Solstice Body Wash work through conventional surface chemistry rather than nano-scale delivery. Activated charcoal in the Unscented Charcoal Bar operates through adsorption at the surface — binding to impurities and rinsing away cleanly. None of these require engineering ingredients to an unnaturally small size to work. For a teen using personal care products every day for years, that distinction is worth understanding.

The science on nanoparticles in personal care is ongoing, and the full picture isn't settled. What's clear is that ingredient particle size matters — not just ingredient identity — and that products built from standard-scale plant and mineral ingredients sidestep the open questions around nano-engineered alternatives entirely.

Last reviewed June 2026 by the Prep U team.

*Information on this site is intended for educational and informational purposes only. Any information on this site is not intended to make claims to any unique individual and/or experience.

For more, see our guide to the natural deodorant for boys.