Drastically lowering basal rates

I couldn’t find a thread that addressed this topic specifically so I started this. Feel free to point me in the right direction if one already exists.

This is pretty simple but I’d like to see if anybody else has had the same issues.

I’ve been Looping since January and intermittently adjusting my settings according to the instructions on seemycgm. Over the last month or so, I have seen my basal rates go down, so much that between 12 am and 6 am, I’m taking 0.1 units per hour an still going low at night. This little insulin seems strange for a 34-year-old male who has had diabetes for 17 years and who 2 months ago was taking between 0.7 and 1.2 units per hour at night with no problems. Has anybody else had such a drastic change in such a short period of time?

Background: When I do my tuning, I’m not in closed loop and I only change one setting per day. I also fast for the time’s I am trying to adjust.

Also, I’m not sure if this is relevant but in August this year I became very resistant to Fiasp and ended up switching back to Novolog (Novorapid) after my daily insulin needs increased from ~34 units to ~54 units with terrible results (it was like pumping water). I’ve been back on Novolog since August 1st.


Have you had any changes to your diet recently? Or any changes in exercise?

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Not really, I just do what I always have. Low carb and run 4x a week.

I notice huge drops in basal when my food intake drops. But if you have not had a recent change, I don’t know what else is happening for you.

Another factor is weight. Have you lost a lot of weight lately?

When there was concern that I was becoming allergic to Humalog earlier this year (which I use in my pump), I was told to switch back and forth between Humalog and Novolog monthly. Apparently some people who develop allergies (or antibodies?) to insulin have to do this to keep their body responsive to it.

In my case, I believe I developed an allergy to something in wine…and my skin was reacting badly to adhesives and my sites were terrible when everything was at its worst. Novolog did seem to perform better for me than Humalog at first, but then when I removed wine from my routine and went back to Humalog, everything has been fine for me again (i.e. my skin stopped reacting to the pod adhesive, my sites started looking and working better, and the Humalog has performed normally for me). I don’t use Novolog anymore or switch back and forth anymore because it is no longer necessary.

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A little but not much, maybe 5lbs. 157 down from 162

So there may be a few factors combining together. A small part of it could be from weight loss.

We have seen times where insulin needs change dramatically at night, but my son is a growing teenager, so it probably doesn’t apply to a 34 y/o.

Are you staying flat with this drastic lowering of insulin at night?

I don’t know the reason for it, but in some sense it doesn’t matter.

It’s absolutely correct for you to take the amount of insulin that your body needs, not some random amount that seems “reasonable”. So if 0.1u is too much, keep reducing it until you find the right amount.

In my case it’s kind of the reverse of your situation: currently I’m taking about 0.15u/hour during the day and 0.8u/h at night (actually there are a few steps in the schedule.)

Whether your low dose overnight is because of residual insulin production, or some pooled subcutaneous insulin that slowly percolates into your bloodstream overnight, or heightened insulin sensitivity overnight doesn’t really matter. Just take the amount of basal you actually need.


I agree that you just take what you need, certainly. Definitely adjust until you find the right amount.

And while it may not matter why, I do think it is helpful to try to figure these things out to make someone more aware of the variables they face.

Diabetes becomes much easier when reduce the idea of “randomness”. Absorption, site differences, length of time with the infusion site, activity, stress, lack of sleep, illness, seasonal changes, hormones, food intake…so many things affect it.

I have seen people on various sites speaking of how random their blood sugar is, and I don’t believe that. We may not always understand it, but there has to be a reason.

So I think that trying to figure these things out can be a beneficial exercise. It is not something a person should stress over. But examining it and trying to figure it out can sometimes be educational, and can make us better at what we do.

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I agree with that 100%. My caution is that for treatment decisions, “the way things actually are today” is more important than “the way logic says things should be” and “the way things used to be.”

Reasoning will sometimes lead us to falsely believe that we understand the cause for what we see. Then when we make treatment decisions based on that belief, we get surprising outcomes, and we can get caught there.

I’ve had times where I just didn’t seem to be able to figure out why my BG was too high. My solution was to return to the ground truth: if my BG is too high I need more insulin. That cuts through the confusion and tells me what I need to do. Same goes for basal tuning. If my BG is going low overnight, I’ve got too much basal overnight. So I probably should take less.


Well stated. I’m with you on it. Sounds like we agree on all aspects of it.


I’ve been experiencing something similar over the past few weeks: increased frequency and depth of overnight lows, which leads to me decreasing my basal settings…then rinse and repeat.

Last night, after treating a low, I was pondering “why my insulin sensitivity has changed so much recently”? For me it’s about the amount and type of Stress in my life .

I’d been unhappy in my last job for quite a while (for a year at least). Two weeks ago, I accepted a transfer to a new job (with the same company) and my husband and I are in the middle of a relocation from Chicago to Dallas! This is both exciting and hectic at the same time. It’s stressful for sure but in a very different way than the stress I’ve been feeling the last year or two.


when you have the lows, are you actually Looping or in manual mode? I know you say you’re off the Loop when you’re testing out the changes, but are the lows first being noticed while looping?
I guess if it’s Loop related, we’ve seen with our son that an overly aggressive ISF can make it so that my son needs hours of a zero temp, essentially, to keep from going low. Also, if you’ve got a higher programmed say at 10pm at night, that extra basal can affect my son and cause lows hours later.

We’ve also noticed that our son needs basically a much higher basal rate at night if he eats a hearty dinner. It’s basically a super extended bolus but practically speaking it would probably be easier to program in a basal rate that is 4X his usual. I’m sure you’ve thought of this but if you’re eating a smaller dinner and eating more earlier in the day, your overnight basal could go down quite a bit. Of course, for us our son is the reverse of you; he takes a 0.1 unit/hr basal rate at night, and can sometimes go up to 0.6 units/hr if he has eaten something like pizza before bedtime, for instance.

Other than reanimating beta cells, that’s all I’ve got!