Women's Health: Discussing "The Drop" (i.e. Insulin Sensitivity Change During Cycle Reset)

I want to start a thread looking at what different women experience regarding insulin sensitivity changes during cycle restart (i.e from PMS through to the start of the next cycle).

Some women state they experience no insulin sensitivity change at all. Others experience major changes. I’m sure there is a lot of room in between the two ends of the spectrum to include women who really do experience some level of sensitivity changes, but may not notice it due to the many layers of “what’s causing what” with blood sugar issues…or it’s so minor as not to be noticed because it could be chalked up to any kind of anomaly.

For me, I tend to see highest insulin resistance on Day 23 of my cycle. I experience decreasing resistance from Day 23 through the end of PMS. Sometimes, as occurred last night, I experience my extreme insulin sensitivity a day or two prior to my next cycle starting. I am still in what would be considered “PMS” and have swung from +10%, to +0%, to -10% basal in the last three days. Attached is my Dexcom graph and annotations. I use this as my example because there were minimal variables impacting my numbers.

In a nutshell, I ate dinner at 5:30PM and was conservative with my pre-bolus because I had noticed increased insulin sensitivity throughout the day. I spiked higher than I wanted to, but saw where it rested and conservatively corrected with half of my normal correction dose. Then my bg slid and slid and slid. The rest is noted on the picture. I have mentioned shower drops before…but I typically only notice those with IOB (i.e. basal is not enough to drop me when combined with a shower). I had virtually no IOB last night and my shower dropped me 40+ points per fingerstick, indicating too much basal. These sorts of events are what I see when I experience “The Drop” due to hormone shifts as mentioned by @Jen. Note that my Dexcom was not totally lining up with the magnitude of swings I was seeing per fingerstick (and feeling).


Yes! I just realized I was about to get my period in the next few days, because I started running low overnight with the same Tresiba dose as usual, and sure enough… I think it’s the progesterone withdrawal most likely that triggers it.


And this is the sort of stuff that I think would help SO many other women if it was discussed more openly!

The following famed sentence, our ONLY sentence of guidance from the medical community, is so old, likely SO inaccurate, and so un-investigated.

Yes, yes, my soapbox. But this has turned out to be a passion of mine.


Hi @T1Allison, Great topic. 43 years ago I learned that most health care guidelines, dosages, theories, etc. are based upon the “average 175 lb male” and here women are still… finding patterns and solutions on our own through communities and conversations like this one.

I’m T2 but use basal and bolus insulin. I have found that I can virtually eliminate the bolus insulin I use when I’m ovulating, and need to increase it days 25 thru 2.


Very interesting! Thanks for sharing that!

You are right on the money!

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Today is my Drop Day. My insulin sensitivity shifted between breakfast and lunch. Luckily I saw it via multiple fingersticks…before I took my standard 8 units for lunch on a work day…I ended up eating my lunch, and then bolusing HALF of my usual bolus an hour after I ate. I bounced…but not any worse than I would have on a non-Drop Day. I’m currently coming down through 180 and I have reduced to a -10% basal.

Some days my blood sugar management is a well oiled machine. Some days my blood sugar management is a well oiled pig…that weighs as much as I do and runs faster than me…that I have to catch and put back in its pen.

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