Lows, treatments and timing

I’m learning a lot with my new venture into CGM. Some questions about lows. What do you consider a low (enough to treat)? Do you use a number or a trend or symptoms? What do you use to treat? And how much do you usually use? How long do you wait with no change before re-treating? Is it different at night vs day, or close to meals vs after meals? I have so many questions because it is different now that I’m using CGM. And because my control is tighter (A1c down from 8.6 to 6.6) I’m having more lows.


Hey, congrats on the tighter control!

It totally depends on the context for me on the majority of your questions. If I’m already low (below 65), and I’m not waiting for a meal to kick in that I recently ate, then I’ll treat the low. The amount of carbs totally depends on how much IOB I have, how low I am, how quickly I’m dropping, and tbh how shaky I’m feeling. If I have lots of IOB, am dropping quickly, and I’m feeling the low a lot then I’ll treat more aggressively with up to around 15g or more if necessary.

Normally though I can use a few skittles (1 skittle roughly is 1g carb) to correct a mild low when I don’t have a bunch of the above factors (when I’m not dropping quickly, when I don’t have a lot of IOB, when I don’t feel like I’m dropping quickly).

I also like using swedish fish and sour patch kids snack packets or gatorade for my lows :smiley: Or whatever is in reach that will kick my number up.

I’ll wait like 5 min-10min to test my blood sugar again, and if I haven’t come up I’ll think about having some more carbs. Totally depends on how low I am though!

I think you’ll end up getting a range for how people like to treat their lows. I think it’s all about getting yourself out of danger while also trying to avoid the spike after


I use a number + trend. Our son can only tell us occasionally if he’s feeling low.

1 Like

This is the kind of thing our endos see a lot, which is why they always wag their fingers and say “Don’t let your A1C go below 8 or you’ll have too many lows.” It’s a valid concern – they’re worried about us becoming hypo unaware – but I’m not convinced the two have to go hand-in-hand (although they often do – unfortunately I’ve had my lowest A1c’s after I’ve been having too many lows). The trick with aiming for tighter control is to intervene sooner – which is where your CGM comes in.

My low alert is set to 3.8 (68) – I’m rarely symptomatic at that point unless I’m dropping really fast, but it gives me time to bump myself up before I would have symptoms. If you find you’re having too many lows, or you go low and stay there despite treatment, you could set your low alert higher, so you’d be treating at maybe 90, and see how that works out for you.

As for how much to treat with, when to retreat, etc., @LarissaW took the words right out of my mouth.


I think as you get down into the 5’s and 6’s in your A1c you need to be extra vigilant to ensure your basal rate is set appropriately. When my son has managed an A1c of 6.1, he also bet his endo that he could lower the number and time in low on his CGM. His endo says this was not possible, but by being attentive and having his basal really dialed in, he managed that feat. So if your basal is finely tuned and you are paying attention to the CGM or using aggressive alerts, I think you can reduce the lows.


I always have glucose tabs with me, and I have my low alert set to 85. When the alert happens, I look at the CGM graph to see whether it is rising (do nothing), steady (do nothing and wait for another possible alert after 20 minutes), or falling. If it is falling, I take some glucose to turn my BG back towards the good range. How much glucose? That depends on how much insulin I have in me (“active insulin” or “IOB insulin on board”), and it depends on how fast I’m falling. My goal is to use up any extra insulin and move my BG back to 100. In my case, 1 glucose tab raises my BG about 10 mg/dL, and 1 glucose tab counteracts about 1u of IOB. But it’s complicated depending on how much digestion is still ahead of me.

Simple example. I ate some carbs 2 hours ago, my BG has fallen to 85, trending down at a medium speed (Dexcom birdbeak angled down, not straight down or double down) and I have 2u IOB. Since it was just carbs, the digestion is mostly done, so I don’t need those 2u of insulin that are still in my system. I’ll take 3 glucose tabs, 2 for the IOB and one to raise 85 to 95.

Another example. I ate pizza 2 hours ago, my BG has fallen to 85 with the arrow straight down, and I have 6u IOB. Pizza is slow to digest, so there’s lots more digestion ahead that will tend to raise my BG. But I’m falling fast and it could be hours before the remaining pizza digestion starts to raise my BG. So I’ll take 6 carb tablets to raise my BG to a safe level, counteract the “momentum” of the rapidly dropping BG, and reduce the amount of remaining IOB so I won’t crash. And I’ll look again in about 20 minutes to see if I need more glucose, or if I took too much. If I’ve already bounced back up to 100, maybe I’ll put on an extended bolus of 3u over 3 hours to help soak up the rest of the pizza as it digests.

All of these strategies are kind of wishy-washy intuitive rather than scientific. And our bodies are all different, so you have to find out what dosing works right for you. In particular, there’s no reason to think that 1 glucose tab will raise your BG 10 mg/dL, but it’s easy to find out by eating one when you are fasting, level, and sedentary to see what happens to the CGM graph over the next hour.

Let me finish with the simple advice, because the details can be overwhelming when you’re in the process of figuring out how your body works.

  1. If your BG is too high, you need more insulin.

  2. If your BG is too low, you need carbs. Glucose tabs are the fastest.

  3. Use frequent small doses of insulin and carbs to keep turning the CGM graph in a good direction. One exception: take a large dose of glucose for self rescue if your CGM graph is plummeting towards a serious low.


@bkh - Thanks for the reply. Those examples are really helpful, and your “simple” advice is very good. The frequent small doses of insulin and carbs is especially helpful. I understand not to take too much insulin too frequently to keep from stacking it, but I tended to think small doses of carbs wasn’t a “real” treatment for low BG but instead “cheating.” Now I see how it can keep me in the lower range without being too high or too low.

1 Like

In my view, that was more of a concern back before CGM, when stacking insulin meant you could crash low with no warning. Since my CGM is trustworthy, stacking insulin isn’t dangerous for me, it is simply another tool to help correct a stubborn high. If I take too much insulin I’ll see it in the CGM graph when it starts to plummet, and even if I don’t notice it, the CGM will alert me so I can correct it with glucose. Of course I try to give myself the right dose of insulin every time, but in any case I can always steer it in a good direction when my prediction turns out wrong.