Cotton is not inherently bad for you. It’s one of the most breathable, skin-friendly fabrics available, and for most people wearing it daily, it poses no health risk. But “cotton” covers a wide range of products, from t-shirts to tampons, and the way cotton is grown, processed, and used determines whether it could cause problems. The concerns worth knowing about fall into a few categories: chemical residues from farming and manufacturing, moisture behavior against your skin, and trace metals in cotton products that go inside your body.
Cotton Clothing and Skin Health
For everyday wear, cotton is generally one of the safest fabric choices. It allows more air to pass through than most synthetic blends. Pure cotton has an air permeability of about 76 mm/s, compared to 58-73 mm/s for cotton-polyester blends. It also conducts heat away from your body far more efficiently than polyester-heavy fabrics, which means it helps regulate temperature against your skin rather than trapping warmth.
Cotton is also less likely to cause body odor than synthetics. Polyester fibers are hydrophobic, meaning they repel water but attract oils. Since skin oils (sebum) are the primary food source for odor-causing bacteria, polyester picks up more bacteria and keeps them more metabolically active. Cotton absorbs water more readily than polyester and binds less sebum, so bacteria tend to be less active on cotton fabric overall.
The trade-off is that cotton holds moisture. If you’re exercising heavily or wearing cotton in cold, wet conditions, it stays damp longer than synthetics. Prolonged skin contact with wet fabric can cause chafing, irritation, or in extreme cases contribute to fungal skin issues. This is why athletic and outdoor gear tends to use synthetic or merino wool fabrics that wick moisture away. For normal daily wear in moderate conditions, cotton’s moisture absorption is a non-issue for most people.
Pesticide and Chemical Residues
Conventional cotton farming uses more pesticides per acre than almost any other crop. Residues from insecticides, herbicides, and defoliants can remain on raw cotton fibers. The question is whether meaningful amounts survive the washing, bleaching, dyeing, and finishing processes that turn raw cotton into a finished product.
For clothing, residue levels on the final garment are typically very low. Your skin is also a strong barrier. Unless you have a specific contact allergy or chemical sensitivity, trace pesticide residues on a finished cotton shirt are unlikely to affect your health. The bigger concern is the chemicals added during manufacturing: formaldehyde-based finishes used to make cotton wrinkle-resistant, synthetic dyes, and softening agents. These are more likely to cause skin irritation, especially in people with eczema or sensitive skin. Washing new cotton clothing before wearing it removes a significant portion of these surface chemicals.
Organic cotton, certified under standards like the Global Organic Textile Standard (GOTS), prohibits a long list of harmful inputs during both farming and processing. GOTS Version 7.0 bans formaldehyde, PFAS (the “forever chemicals” found in many stain-resistant treatments), heavy metal-containing dyes, phthalate plasticizers, endocrine disruptors, flame retardants, and dozens of other compounds. If chemical exposure from cotton concerns you, GOTS-certified products offer the most rigorous protections currently available.
Metals in Tampons and Internal Products
The more serious health question involves cotton products that contact mucous membranes, particularly tampons. A 2024 study published in Environment International tested 30 tampons across 14 brands and found detectable levels of 16 different metals, including lead, cadmium, and arsenic. The average lead concentration was 120 nanograms per gram of tampon material, with cadmium at about 6.7 ng/g and arsenic at 2.6 ng/g.
Notably, organic tampons were not consistently safer. Lead concentrations were higher in non-organic tampons, but arsenic levels were actually higher in organic ones. No single category of tampon had lower concentrations across all metals. The metals likely come from multiple sources: the soil where cotton is grown, water used in irrigation, and chemicals used during manufacturing. Because vaginal tissue is highly absorbent, even low-level metal exposure through this route could be more significant than the same exposure on intact skin.
Researchers are still working to determine whether the amounts detected are high enough to pose a real health risk with typical use. The concentrations are measured in nanograms, which are extremely small quantities. But the exposure is repeated over decades for most menstruating people, and certain metals like lead and cadmium accumulate in the body over time with no known safe threshold. This is an area where the evidence is still developing, but the findings are enough to take seriously.
Cotton Dust and Occupational Exposure
One context where cotton is genuinely harmful involves people who work directly with raw cotton fibers. Byssinosis, sometimes called “brown lung disease,” is a respiratory condition caused by inhaling cotton dust in textile mills and processing facilities. Symptoms include chest tightness, coughing, and shortness of breath, typically worse at the start of the work week after time away from exposure. With prolonged exposure over years, the condition can become chronic and irreversible. This is strictly an occupational hazard and has no relevance to wearing cotton clothing or using cotton products at home.
How Cotton Compares to Alternatives
When people ask whether cotton is “bad,” they’re often weighing it against other options. Here’s how the main fabric types stack up for health:
- Polyester and nylon: These synthetic fabrics trap more odor-causing bacteria and don’t breathe as well as cotton. They’re derived from petroleum and can contain their own chemical additives. They do dry faster, making them better for intense physical activity.
- Bamboo and rayon: Often marketed as natural, but most bamboo fabric is chemically processed rayon. The manufacturing process uses harsh solvents, and the “natural” label can be misleading. The finished fabric is soft and breathable but not necessarily cleaner than cotton.
- Merino wool: Naturally antimicrobial, breathable, and moisture-wicking. It’s one of the best-performing fabrics for skin health but comes at a higher cost.
- Organic cotton: Same fiber as conventional cotton with stricter limits on chemical inputs during growing and processing. It doesn’t eliminate all concerns (as the tampon metal study showed), but it reduces exposure to synthetic pesticides and processing chemicals.
For most people in most situations, cotton remains a solid choice for clothing and bedding. The fiber itself is not harmful. The concerns that do exist center on what’s added to cotton during farming and manufacturing, and on trace contaminants in products used internally. Choosing certified organic cotton, washing new items before use, and staying aware of evolving research on internal-use products are the most practical steps you can take.