I was amused, in a way, to see a couple of insurance companies last year (when checking plans) that cover Fiasp while covering Humalog (i.e. lispro) but not Novolog (aspart; Fiasp without the nicotinamide).
I’ve been able to use all three interchangeably but currently I prefer a fourth, lispro-aabc, marketed as Lyumjev as it seems faster without me being able to determine whether there is any actual difference from Humalog.
I suspect this is all hoopla and that there is no difference between the insulins themselvs, rather the problems come down to the precise mix in the preservatives (my various insulins seem to use m-cresol). The issue is discussed here:
I found @CarlosLuis 's early 2025 response particularly interesting:
See the remainder of the thread for the link to Tandem’s observation. Maybe it’s canula (plastic) dependent but clearly by that argument it would also be preservative dependent. Site reactions maybe the same, but what about the adhesive interaction?
I don’t see Tandem blaming either the plastic (their canula) or the preservative in that link; neither word occurs in the PDF (the closest leading substrings are “representative” and “replacement”). Cannula gets 39 matches but mostly the ones of interest are about the cannula breaking or becoming completely detached, “dislodged”; the others are instructions.
@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.
There is not a single scientific paper or study done in the last 20 plus years noting any reaction or efficacy issue with insulin used or stored in a plastic container. Any study or paper written mentioning an efficacy or crystallization with any pump approved insulins sold today. It is a shame to see this myth continue to be site by so mane and intern causing confusion and stress to pump users. Would be great if those promoting this “reacts with plastic” myth would step up and remove their incorrect and negative impacting comments.
This is probably not relevant but it is entertaining:
Chemical stability of a tube in liquid transport is amazingly well researched and that does include when the transported liquid contains phenols:
Search for both “phenol” and “cresol” (m-Cresol is a phenol).
IMO there is no way that any manufacturer of an insulin pump would not have read the charts; they are widely published. So I’m sort-of agreeing but because I believe manufacturers know what they are doing, not because they haven’t done the research or checked the conslusions.
Not insulin related. Again pushing a false narrative really helps no one. Look for specific studies that demonstrate an issue with pump approved insulins and plastic.