Does Silicone Have Microplastics?

What is silicone?

Silicone is a synthetic polymer — but it is not technically a plastic. Plastics have a carbon-chain backbone; silicone has a silicon-oxygen backbone. This is part of why it is marketed as a safer alternative. It is heat-resistant, flexible, and widely used in kitchen tools, food storage bags, baby products, and medical devices.

The real question isn't whether silicone is technically a plastic — it's whether it releases particles or chemicals into food under everyday use. That's what the research addresses.

What the research shows

The short answer: silicone doesn't release traditional microplastics. What it does release — silicone nanoplastics and chemical migrants — raises its own concerns.

Feng et al. (2023) in Science of the Total Environment tested 31 silicone kitchenwares — baking moulds, plates, chopping boards, and cups. They found that 96% were toxic to cells and 84% showed hormone-disrupting effects, including impacts on both estrogen and androgen activity. At least 26 organic compounds and 21 metals were detected migrating out of the products.

The main chemicals driving these effects were methylsiloxanes — D4, D5, and D6. These are flagged by the European Chemicals Agency as substances of very high concern, linked to fertility damage and hormone disruption in animal studies. Migration was higher at elevated temperatures — which is exactly how most silicone bakeware and cooking utensils are used.

Notably, the 11 baby bottle nipples in the same study performed significantly better — none showed toxic or hormonal effects. This suggests that the tighter regulation applied to infant products may result in safer silicone formulations.

On the particle side, Ekvall et al. (2023) in PLOS ONE confirmed that silicone releases silicone nanoplastics under mechanical stress. Boiling alone did not release a significant number of particles — but when the boiled silicone was then subjected to mechanical breakdown, it released approximately twice the number of nanoplastics compared to unboiled material. The study also tested acute toxicity and found the silicone nanoplastics did not affect survival in the test organism, though this covers acute toxicity only and does not address longer-term effects.

Is silicone safer than plastic?

The honest answer is: it depends on what you're comparing and how you're using it. Silicone doesn't carry the same BPA or phthalate concerns associated with some hard plastics, and it doesn't melt or degrade in the way thin polypropylene does when heated. But the Feng et al. findings make clear it's not inert — chemical migration happens, and it increases with heat.

• High-temperature use carries the most risk — baking moulds and oven-safe cookware are where migration of methylsiloxanes is most likely to occur.
• Not all silicone products are the same — the study found variation between products, and the better-performing bottle nipples suggest formulation matters. Cheaper products with more additives and colorants may carry higher risk.
• Mechanical wear releases silicone nanoplastics — silicone used with abrasive cleaners or utensils will shed particles over time, particularly if the material has previously been boiled.
• Cold storage is lower risk — the migration effects in Feng et al. were measured at cooking temperatures; using silicone bags for cold food storage is a different risk profile.

Practical guidance

For high-heat applications — baking moulds, oven trays, cooking utensils — glass, stainless steel, and cast iron are the safest choices based on current evidence. These materials don't release methylsiloxanes or nanoparticles into food. For cold food storage or low-temperature uses, silicone is lower risk, though not zero risk.

If you do use silicone kitchenware, replacing items that are visibly degraded, discoloured, or heavily scratched is reasonable — wear increases particle release. Avoiding abrasive scouring pads when cleaning silicone also helps.

What the research doesn't yet tell us

The Feng et al. study used accelerated migration conditions — 95% ethanol at 70°C — which are designed to simulate extended real-world use in a shorter timeframe. Whether everyday cooking at typical oven temperatures produces the same migration levels in actual food is not yet established. The study also sourced products from the Chinese market, so it isn't directly generalisable to products sold elsewhere under different regulatory frameworks. What it does establish is that chemical migration from silicone kitchenware is real and measurable, and that the compounds migrating have known biological activity.