The Problem With "BPA-Free": Why It's Not the Same as Plastic-Free
"BPA-Free" became a marketing word before it became a meaningful one.
In the early 2010s, BPA (Bisphenol-A) became a household villain. Studies linked it to hormone disruption, and consumers, rightfully, demanded alternatives. Brands responded fast.
Almost too fast.
The industry didn't remove plastic:
It removed one specific chemical and kept the rest of the polymer structure largely the same.
BPS became the common replacement:
Bisphenol-S (BPS) is structurally similar to BPA and has become one of the most common substitutes used across consumer plastics since the BPA scare.
Early research raises similar concerns:
A growing body of research suggests BPS may carry comparable hormone-disrupting properties to the chemical it replaced, meaning the "fix" may not be the fix people assumed it was.¹
Why This Matters More for Things You Drink From Daily
A plastic container you use once a year is a different risk profile to one you use multiple times per day, every day, for years.
Frequency multiplies exposure:
A shaker bottle used twice daily sees far more cumulative material stress, and far more potential chemical exposure, than almost any other plastic item in your kitchen.
Heat and acidity accelerate the issue:
Plastic shakers regularly get exposed to heat in ways people don't think about: hot water when cleaning, sitting in a car in summer, or being left in direct sunlight on the way to the gym. They're also in contact with mildly acidic liquids during use. Both heat and acidity accelerate plastic degradation and chemical migration into whatever's inside.²
"Food-grade" doesn't mean "inert":
Food-grade plastic ratings indicate a chemical was tested for general food contact, not that the material is incapable of any leaching or shedding under repeated, high-frequency use.
What "Actually Plastic-Free" Looks Like
No BPA. No BPS. No polymer, anywhere:
Genuinely plastic-free means the entire product, body, lid, and seal, contains zero plastic components, not just the absence of one flagged chemical.
Stainless steel doesn't need a "free" label:
You'll never see "BPA-free" on a piece of surgical steel, because the entire conversation about chemical leaching simply doesn't apply to non-polymer materials.
The seal matters as much as the body:
A "plastic-free" bottle with a standard rubber or plastic-blend seal hasn't actually solved the problem. It's moved it to a smaller, less visible part of the product.
This Is the Standard We Built To
The Steel Shaker doesn't carry a "BPA-free" label, because that's the wrong question entirely. It's 100% stainless steel with a food-grade silicone seal: zero plastic, full stop, no asterisk.
Sources
- Rochester, J.R., Bolden, A.L. "Bisphenol S and F: A Systematic Review and Comparison of the Hormonal Activity of Bisphenol A Substitutes." Environmental Health Perspectives 123(7), 2015. A systematic review of 32 studies (25 in vitro, 7 in vivo) found that BPS and BPF show hormonal potency in the same order of magnitude as BPA, with estrogenic, anti-estrogenic, androgenic, and anti-androgenic activity. The study concluded that BPS and BPF are as hormonally active as BPA and have endocrine-disrupting effects. URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4492270/
Supporting: Pelch, K.E. et al. "Characterization of Estrogenic and Androgenic Activities for Bisphenol A-like Chemicals (BPs)." Toxicological Sciences 172(1), November 2019. Evaluated 22 BPA-like chemicals across in vitro cell models, confirming BPS induces estrogen receptor activity and shares androgenic disruption properties with BPA. URL: https://pubmed.ncbi.nlm.nih.gov/31388671/
- Massahi, T., Omer, A.K., Kiani, A. et al. "A simulation study on the temperature-dependent release of endocrine-disrupting chemicals from polypropylene and polystyrene containers." Scientific Reports 15, 19318 (2025). Found that chemical release from plastic containers increases significantly with rising temperature, with elevated concentrations of endocrine-disrupting chemicals migrating from polypropylene at each temperature point tested (40°C, 60°C, 80°C, 100°C). URL: https://www.nature.com/articles/s41598-025-05036-7
Supporting: Liu, H. et al. "Exposure to leachates of plastic food containers disturbs glucose and lipid metabolism." Ecotoxicology and Environmental Safety 289, January 2025. Found that leachates from heat-treated polypropylene plastic food containers prompt intracellular lipid accumulation and alter metabolic gene expression, demonstrating measurable health impact from heat-accelerated plastic leaching. URL: https://www.sciencedirect.com/science/article/pii/S0147651324015744
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