[Tracy9]

Activated charcoal can be very adsorbent. This means that if you open a zip lock bag, put 500 grams of good quality activated charcoal inside, seal the zip lock shut, when you come back in 10 hours the zip lock can be all wrinkled and look like it’s become vacuum sealed. 

This adsorbency is what also helps gives it it’s wonderful properties.

I am not an expert on cosmetic materials or tube materials, but I know charcoal and there is a chance that the suction force caused by adsorption can degrade the structural integrity of your plastic tube.

A simple way to test this further, you can use 500g of your activated charcoal to see if it does create a vacuum seal in a ziplock bag. If it doesn’t, it’s probably not that adsorbent and less likely to cause that packaging structural degradation. Hope this helps.