--- title: 'Why Glass Bottles Aren''t As Microplastic Free As You Think They Are' source: 'https://youtube.com/watch?v=lPVPrVcc5OY' video_id: 'lPVPrVcc5OY' date: 2026-09-19 duration_sec: 156 channel: 'Siim Land' --- # Why Glass Bottles Aren't As Microplastic Free As You Think They Are > Source: [Why Glass Bottles Aren't As Microplastic Free As You Think They Are](https://youtube.com/watch?v=lPVPrVcc5OY) ## Summary A recent study challenges the assumption that glass bottles are microplastic-free, revealing that drinks in glass bottles can contain more microplastics than those in plastic bottles. The contamination is traced to the metal bottle caps, not the glass itself, with friction and paint fragments being the primary culprits. Despite this, glass remains the best overall choice for bottled water due to its resistance to heat and sunlight, which reduces microplastic leaching during transport. ### Key Points - **Surprising finding: glass bottles contain more microplastics** [00:00] — A study found that drinks in glass bottles contained more microplastics than drinks in plastic bottles, contradicting common assumptions. - **Microplastic counts by container type** [00:14] — Bottled water in glass averaged 4.5 ± 1.2 particles per liter vs 1.6 ± 1.7 in plastic. Small glass bottles averaged 133.7 ± 15.9 particles per liter vs 31.8 ± 17.3 in cans. - **Source of contamination: bottle caps, not glass** [00:40] — Microplastic particles matched the color and chemical composition of the polyester-based paint on metal bottle caps, suggesting friction between cap and bottle creates fragments. - **Experimental confirmation** [00:53] — Cleaning the caps before sealing reduced microplastic contamination by roughly 70% compared to untreated caps, confirming the cap as the source. - **Glass still has advantages over plastic** [01:09] — Glass is more resistant to heat and sunlight, which break down plastic bottles and leach more microplastics into water. Glass bottles exposed to sun leach far less. - **Cans also have a plastic lining** [01:41] — Tin cans contain a plastic layer inside to prevent tin leakage, so water is essentially sitting in a plastic bag covered by tin. Tin still protects against sunlight. - **Glass is still the best option** [02:09] — Despite the cap issue, glass bottles remain the best choice overall. Microplastics are a minor health concern compared to obesity and low VO2 max. - **Health assessment promotion** [02:22] — The creator promotes a 3-minute health percentile assessment that evaluates biomarkers, fitness, body composition, and lifestyle to identify key health bottlenecks. ### Conclusion While glass bottles can introduce microplastics from their caps, they remain the best container choice for water due to their resistance to heat and sunlight. Microplastics are a smaller health concern than major lifestyle factors like obesity and low fitness. ## Transcript You might think that drinking from a glass bottle protects you from microplastics. But a recent study found something surprising. Drinks in glass bottles actually contained more microplastics than drinks in plastic bottles. For bottled water, the study found an average of 4.5 ± 1.2 microplastic particles per liter in glass bottles, compared to 1.6 ± 1.7 microplastic particles per liter in plastic bottles. Now the difference was larger for certain other beverages. in small glass bottles averaged 133.7 ± 15.9 particles per liter compared to 31.8 ± 17.3 particles per liter in cans. Now here's the weird part, it's not the glass that is leaking the microplastics. Researchers noticed that many of the microplastic particles were the same color as the paint on the metal bottle caps. When they analyzed them, their chemical composition also matched the caps' polyester-based paint. The researchers thought that the friction between the bottle caps and the bottle itself creates these tiny scratches and fragments that then lead some microplastics into the water itself. They even tested this experimentally. When they cleaned the caps before sealing the bottles, microplastic contamination dropped by roughly 70% compared to untreated caps. So glass bottles aren necessarily worse than plastic bottles The glass bottles still have a lot of advantages over plastic bottles The biggest one is that the glass bottle itself is more resistant to things like heat and sunlight that would break down microplastics inside a plastic bottle So if you have a plastic bottle sitting outside and the sun is going to melt a lot of the microplastics into the water, whereas if you have a glass bottle sitting out in the sun, then it's not going to happen nearly as much, probably not at all. So it's still in most cases better to drink water from a glass bottle than from a plastic bottle, because most bottle of water travels a lot of distances, it's exposed to more heat and sunlight during the travel. So during the travel, the glass bottle will have less microplastics leached into it through the sun and the heat. And that applies to the cans as well. Inside a tin can, there is a plastic layer that prevents the tin from leaking into the water, but the water is still sitting inside a plastic bag, basically. It's just covered outside with a tin layer. So even the tin layer is still better because the tin will protect the water against some of the sunlight. Out of all these options, the glass bottle is still the best. But still, microplastics are still part of a small picture when it comes to your overall health. You shouldn't get too scared of them, especially if you're still a little bit fat or if you have a low year to max, for example. Those are much bigger concerns. If you want to see where your overall health actually ranks up for your age, take my 3-minute health percent assessment. It looks at your biomarkers, fitness, body composition, and lifestyle, gives you your health percentile, and shows you your biggest bottlenecks and what to improve first. Click the link below to start now.