Most exercise water bottles are made from plastic, and about 10 percent of them contain the chemical BPA, a highly suspected carcinogen and hormone blocker. The Food and Drug Administration plans to decide by October 31, 2022 whether to ban BPA from most containers and utensils that come in contact with food. They have already banned BPA from baby bottles. “Most Americans get 5,000 times more BPA in their daily diet than the EFSA (European Food Safety Authority) expert panel says is safe,” said Tom Neltner, Environmental Defense Fund’s Senior Director, Safer Chemicals (, June 2, 2022). Even plastic products labeled BPA-free can still contain other substances such as BPS or PVC that may be carcinogens.

At this point, glass appears to be the safest material for water bottles, but glass breaks so readily that most people will not use it during exercise. Metal water bottles can release metals into drinks (Bull Environ Contam Toxicol, 1979;21:600–603), so almost all metal bottles except those made from stainless steel are lined with plastic. Stainless steel water bottles may be your best choice during exercise because they do not leach metals into plain water, tea, coffee or milk (Science of The Total Environment, Jan 15, 2009;407(3),1089-1096). However, some people are still concerned about stainless steel exercise bottles. Acid drinks, such as most sodas, can increase release of metals into drinks (Int J Electrochem Sci, 2015;10:3792-3802). Stainless steel bottles did leach nickel, chromium, and iron into lemon, orange, mango and strawberry juices after five days (Int J Electrochem Sci, March 23, 2015;10:3792 – 3802), and vinegar leached nickel from stainless steel cups (J South Carolina Academy of Science, 2018;16 (2)). Heating stainless steel at high temperatures can release significant amounts of metals during cooking (J Agric Food Chem, Oct 12, 2013;61(39):9495–9501).

My Recommendations
We need more studies, but stainless steel may be your best choice for water bottles when you exercise because they do not appear to leach significant amounts of metals into cold drinks. Bottles made from other metals such as aluminum could leach the metals into your drink, so they are all lined with plastics, some of which can harm you. Plastic water bottles can leach various potentially harmful substances into drinks, and glass bottles are at high risk for breaking. While we wait for the FDA decision, Diana and I have gotten rid of all our plastic water bottles and switched to stainless steel. Amazon has some very nice ones that fit into our standard water bottle holders.