Microfiber vs Rayon

Allergies:

Generally hypoallergenic due to synthetic nature that resists dust mites, mold, and mildew better than natural materials. Free from animal proteins that trigger feather allergies. However, some individuals may be sensitive to polyester itself or chemical treatments. Regular washing (every 3-4 months) is essential to prevent allergen accumulation. Research shows microfiber pillows can harbor respiratory pathogens - studies found high permeability (82-95%) for aerosol particles, meaning viruses and bacteria can penetrate the fabric and accumulate in fill. Not suitable for those allergic to synthetic materials or sensitive to chemical treatments like flame retardants.

Dust Mites:

Synthetic polyester fibers naturally resist dust mite colonization better than natural materials when new and clean. The smooth, non-porous surface of polyester provides fewer places for mites to attach compared to cotton or down. However, this advantage diminishes without regular washing - dust mites can still colonize surface layers and accumulated skin cells. Studies confirm synthetic pillows require regular laundering (every 3-4 months) to maintain dust mite resistance. Unlike claims of permanent protection, microfiber pillows accumulate allergens over time just like other materials. Machine washability in hot water offers advantage for killing mites and removing allergen accumulation.

Chemical Concerns:

Significant chemical concerns exist with microfiber pillows. Studies show polyester pillows can contain flame retardants (PBDEs) at levels of 107 parts per million - lower than polyurethane foam (3,646 ppm) but still present. These flame retardants are linked to cancer, reproductive issues, and neurological problems. Manufacturing process releases VOCs during production. New pillows may off-gas chemicals causing odors. A 2020 study found people sleeping on microfiber sheets had elevated phthalate levels in urine. Not naturally occurring - created through chemical processes using petroleum derivatives. Look for OEKO-TEX Standard 100 certification ensuring testing for 1,000+ harmful substances including formaldehyde, heavy metals, pesticides, and phthalates. CertiPUR-US certification available for some blended foam/microfiber products.

Allergies:

Rayon can be hypoallergenic when properly manufactured and certified OEKO-TEX Standard 100, ensuring harmful chemical residues removed during finishing. The smooth, rounded cellulose fiber structure naturally resists trapping allergens compared to rougher cotton fibers. However, significant concerns exist regarding residual manufacturing chemicals - improperly processed rayon may contain traces of carbon disulfide, sodium hydroxide, sulfuric acid, ammonia, or other processing chemicals triggering reactions in chemically-sensitive individuals. Always verify OEKO-TEX Standard 100 certification confirming fabric tested free from harmful substances including formaldehyde, heavy metals, pesticides, and carcinogenic dyes. Some individuals may have sensitivity to rayon/viscose cellulose fibers themselves regardless of processing quality. Standard weave rayon does not provide complete dust mite barrier - combine with allergen-proof pillow protectors achieving pore sizes under 10 microns for maximum protection.

Dust Mites:

Rayon provides moderate protection against dust mites through moisture-wicking properties removing humidity mites require for survival and reproduction. The smooth cellulose fiber surface accumulates fewer dead skin cells (dust mite food source) compared to rougher cotton textures with greater surface area. Moisture absorption capability helps maintain drier environment less hospitable to dust mite colonization - mites thrive in humidity above 50% relative humidity. However, standard rayon weave does not provide physical barrier preventing dust mites from penetrating through fabric. For maximum dust mite protection, use rayon pillowcases over allergen-proof pillow protectors with pore sizes under 10 microns creating complete impermeable barrier. Regular washing in warm water (40°C if fabric tolerates - verify manufacturer instructions as some rayon requires cold only) effectively kills dust mites and removes accumulated allergens. Despite moisture management benefits, rayon itself does not possess antimicrobial or dust mite repellent properties - protection comes from environmental conditions rather than inherent material characteristics.

Chemical Concerns:

SERIOUS chemical concerns exist throughout rayon manufacturing process despite natural cellulose origins. The viscose process uses highly toxic chemicals including carbon disulfide (causes psychosis, neurological damage, cardiovascular disease, blindness), sodium hydroxide (caustic soda), sulfuric acid, ammonia, and various bleaching agents. Carbon disulfide toxicity has been well-documented since the 1800s with devastating effects on rayon workers. Studies from 1930s revealed 30% of American rayon workers experienced significant health impacts. Medical research documents severe peripheral neuropathy, cerebral atrophy, heart disease, and psychiatric illness among exposed workers. Approximately 50% of chemicals released as hazardous air and water pollutants in many factories globally. Modern closed-loop facilities can recover 90-99% of chemicals minimizing environmental impact and worker exposure, but these systems not universally implemented, especially in Asia where production concentrated. Properly finished fabric should be safe for consumer skin contact when certified OEKO-TEX Standard 100, confirming harmful residues removed through washing. However, manufacturing process remains chemically intensive with serious occupational health and environmental consequences. For truly chemical-free options, choose mechanically-processed natural fibers or lyocell using safer amine oxide closed-loop process.