Cotton and oxygen scavengers in the bottle

Yay! Finally...another blog post!

Anyway, the question comes from Wei Ling, and her question goes

Is it true that we must remove cotton or oxygen absorber from bottle medication or vitamins once opened? Why?

Well...first and foremost, you have to understand the purposes of having cotton and/or an oxygen scavenger in the bottle of either you over-the-counter (OTC) drugs or nutritional supplements.

Both cotton and the oxygen scavenger sachets functions the same, just in the different way. They both are inserted into the bottle to minimize oxygen in the bottle. Cotton fills in head space in the bottle; the less head space in the bottle, the less air, hence less oxygen. The oxygen scavenger works more directly by binding free oxygen in the bottle after sealing, hence creating an anaerobic or oxygen-free environment.

We all understand that oxygen oxidizes, especially the active components in your OTC drugs and/or supplements. Take ascorbic acid (or more widely known as vitamin C) as an example:


Figure 1. Oxidation of ascorbic acid.

With the presence of oxygen, oxidation occurs from the antioxidant ascorbic acid to the oxidized dehydroascorbic acid, and you don't want dehydroascorbic acid in your expensive vitamin C supplements.

So, bottom line answer......would I keep the cotton and oxygen scavenger in the bottle once it's opened? No. Why? Just because now that the bottle is opened, and will be opened at least once a day, I don't feel the need for anybody to reinsert the cotton and oxypads back into the bottle. One easy way to minimize oxidation is to simply store your medication and supplements in the refrigerator, because we all know that the rate of oxidation is directly proportional with storage temperature. In the other words, the colder it is, the better.

Well....hope this isn't information overload....