The term “non-nano” is a consumer label indicating the particle size of ingredients used in sunscreens and certain cosmetics. This designation is primarily found on mineral-based products, which utilize active ingredients like zinc oxide and titanium dioxide for UV protection. The label distinguishes products containing larger particles from those engineered using nanotechnology. It provides shoppers with a simple reference point regarding the physical nature of the UV filters.
Defining the Scale: What is Nanotechnology?
Nanotechnology involves manipulating matter on an atomic and molecular scale, specifically within the range of one to 100 nanometers. A nanometer (nm) is a unit of length equal to one billionth of a meter. A single nanometer is 100,000 times smaller than the width of an average human hair.
Materials are engineered at this scale because their properties can change dramatically when dimensions are reduced to the nano-range. This reduction can enhance characteristics such as reactivity, strength, or optical behavior, which is desirable in many commercial and industrial applications. Nanomaterials are used across various sectors, including medicine, electronics, and cosmetic formulations.
Understanding the “Non-Nano” Label
The “non-nano” label signifies that functional particles have an average size greater than the established regulatory threshold of 100 nanometers. This larger particle size is achieved by intentionally grinding the mineral ingredients less finely than is done for nano-sized formulations. The main purpose of using non-nano particles is to ensure the material remains on the outermost layer of the skin after application.
In mineral sunscreens, zinc oxide and titanium dioxide particles reflect and scatter ultraviolet (UV) light, acting as a physical barrier. When these minerals are used in their non-nano form, the larger particles scatter visible light, resulting in a noticeable white or opaque cast on the skin. Conversely, manufacturers use nano-sized particles to reduce this white appearance, making the sunscreen more cosmetically transparent and appealing. While both particle sizes offer broad-spectrum UV protection, the choice often comes down to how they look and feel on the skin.
Why Particle Size Matters for Product Safety
Particle size is a significant factor in consumer concern regarding both potential health and environmental risks. Non-nano particles are favored by those concerned about skin absorption, as their larger size prevents them from passing through the intact stratum corneum, the skin’s protective outer layer. Studies on nano-sized mineral filters largely conclude they do not penetrate beyond this outermost layer, though minimal absorption may occur if the skin barrier is damaged. The non-nano preference is based on the theory that these particles are too massive to enter the bloodstream or viable skin cells.
Concerns arise regarding the inhalation of nano-sized particles, particularly in aerosol or powder sunscreens. When inhaled, these extremely small particles may be difficult for the lungs to clear and could potentially pass into the bloodstream, leading to inflammation or other health effects. While some field tests suggest that actual user exposure to nanoparticles from spray sunscreens is hundreds of times below recommended limits, regulatory bodies still advise against using nano-titanium dioxide in applications that could lead to significant inhalation. Choosing non-nano formulations in sprays and powders is a precautionary measure to mitigate this specific inhalation risk.
The environmental impact of sunscreen ingredients is a reason consumers seek the non-nano distinction. When washed off, nano-sized zinc oxide and titanium dioxide can enter aquatic environments, where they are considered emerging contaminants. Research indicates that nano-zinc oxide is highly toxic to marine organisms, causing damage to coral, algae, and fish through mechanisms like the generation of reactive oxygen species and bioaccumulation. Non-nano particles are considered a more environmentally conscious choice because their larger size causes them to settle harmlessly to the seafloor rather than being readily absorbed or dissolved by marine life.