# Effect of preservatives on insulin effectivity and site issues

**URL:** <https://forum.fudiabetes.org/t/effect-of-preservatives-on-insulin-effectivity-and-site-issues/16019>\
**Category:** Tips, Tech & Gear\
**Tags:** insulin\
**Created:** [May 1, 2026, 11:12pm UTC](https://forum.fudiabetes.org/t/effect-of-preservatives-on-insulin-effectivity-and-site-issues/16019 "2026-05-01T23:12:23Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![CarlosLuis](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/carlosluis/32/11389_2.png) [@CarlosLuis](https://forum.fudiabetes.org/u/CarlosLuis)\
**Post date:** [May 2, 2026, 1:47am UTC](https://forum.fudiabetes.org/t/effect-of-preservatives-on-insulin-effectivity-and-site-issues/16019/4 "2026-05-02T01:47:02Z")

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> [@Effectiveness of NovoLog vs Humalog in a pump](https://forum.fudiabetes.org/t/effectiveness-of-novolog-vs-humalog-in-a-pump/10978/22):
>
> It’s something to do with the reaction to the preservatives and the plastics.

@jbowler I don’t think it is tubing or cannula but the plastic reservoir bag. I think most pumps use a hard plastic cylinder reservoir except possibly Twiist.

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