Symlin, Insulin bolusing, and crazy bg's

I just started the Symlin Pen last week. I am up to 45mcg per meal. At first, it was great! I really didn't have any problem with lows or highs, it just seemed to help "round out" the spikes.

Now, I'm having lots of trouble. If I stick to my 15 minute premeal bolus + symlin shot and eat my meal, I start dropping. I usually end up in the 40's about 30 minutes after eating. I correct with glucose tabs and then, I skyrocked for a few hours later. It just doesn't make sense to me.

I have reduced my bolus amounts by 75%, and am using a squarewave/extended bolus option in my PDM so that nothing is delivered upfront (unless I'm high and need correction for that) and all of my meal bolus is given over 1.5 hrs. Nothing I do seems to avoid the post-meal rollercoaster effect that I'm having.

Does anyone else have this problem? What do you do?

Hi Sarah,

I had similar problems in the past and this is what my endocrinologist recommended. He actually has type 1 himself and he says he does the same thing with his meals. What I do is:

  1. Take Symlin immediately before eating (like 1-5 minutes prior to first bite).
  2. Take insulin immediately AFTER eating (just after last bite OR 15-20 minutes after first bite if I’m eating real slowly).
  3. I also do a square/extended bolus over 30 minutes.

This has worked great for me. The hardest part for me was just remembering to bolus after meals. In the beginning, I was not in the habit of it and forgot sometimes (with disastrous results, of course).

Hope this helps and good luck to you!

Do you take the full insulin bolus amount or do you still have to cut yours in half?

I had the exact same problem, this is what works for me now with amazing results…

I eat FIRST, then bolus exact carb:insulin ratio as I always have and take 15mcg symlin right after eating. I think this way some food starts digesting to prevent the lows and I dont go high 2-4 hrs post meal any more either, unless its a high fat meal. That I still have to work on.

I hope to up my symlin to 30 mcg to help with appetite suppresion but I need a day or so where Im not so crazy busy to try it, I hate to go low at work (hairstylist)

I also did try 30 mcg before meat, eat right away and take ful dose insulin 1 hour post meal. I set my pump to do a bg reminder 1 hour after eating (had to deliver .1u for his option) to remind me to bolus. This became more of a pain bc I was stacking insulin, had active insulin at next meal etc. But it did sort of work and even out my #'s

FYI, my A1c is down from 8 to 7 in just 6 months, this is the lowest my A1c has been my entire life!!!

Hi Sarah - I did have this problem when I first tried Symlin - but I wasn’t on a pump so I could not do the extended or, in my pump, the combo bonus. But now I have a pump and have been more successful.
But, on top of that - I NEVER bolus with my meal - I wait about 1 hour after eating (sometimes 45 min) - THEN I use the combo bolus, because that’s about when my BG begins to rise. The amount of time and percentages depend on what I eat. Also - I couldn’t do a true 50% reduction when I first started - it was more like 70%. The amylin slowly builds up in your system.

Have you read Jason’s guides? Read all 3 -

You should also know that I now use a combo for EVERY meal, whether I’m using Symlin or not, and no matter the content of the food. This, plus using TAG (accounting for my protein and fat intake - has been absolutely revolutionary for me and my results.).-…

Finally, I should share that I limit my carbs to about 20 to 30 per meal, once in awhile 40 - always either veggies or extremely complex/high fiber carbs. I subscribe to the notion that control is much more attainable if you don’t overstress the system.

Let me know if you need any further support, Sarah. Good luck.
My last few A1c’s have been 5.5, 5.6, 5.4.


I spoke with the Symlin people about this. They explained that if you take the symlin before the meal and the bolus after the meal, you should level ok. Otherwise they said it could drop so fast you won’t be able to get it back up with the traditional methods. I have tried this and it works great. Talk to your doctor and see what he says.

meal, not meat

squarewave/extended bolus…
…I’ve not heard that term that I can recall… I’ve used “extended bolus”…Clarify please??

I think different pumps have different descriptions - for my Animas Ping, it’s called a combo. Generally, it refers to releasing your bolus over time (as you choose) and in increments chosen.

Cheri’s right.
The “square wave” is a MM specific term (if I remember correctly), which is just an extended bolus. Another term that you might see is a “dual wave”. That’s just doing a combo of a regular bolus and a square/extended bolus together. It’s nothing out of the ordinary of what you’ve already been doing though :slight_smile:

I’m so glad that Sarah K posted this question. I’ve been using Symlin for over a year and had limited success with it…mostly because I was not instructed on how to use it. After reading this post and the links mentioned in the responses I feel that maybe I can keep trying to get it right.

Can someone post an explanation or a link that explains the ‘extended bolus - squarewave or dual bolus’. I use the OmniPod insulin management system and I’ve never used the extended bolus, nor had it explained to me.

Hi Mayumi -

I’m hoping that someone else who uses the Omni can explain it for you. On the Animas Ping (what I use) it is called a combo bolus - so that means some of the bolus now, and the rest of it over time. You choose the amount of the bolus, then the spread of time - 1/2, 1 hr, 1.5, etc. - then the % to be released now and later. 70%-30%, 60%-40%, 50%-50% (based on what was in the meal).

Thanks Cheri for your explanation. I take it that the % is something that a person learns through trial and error?

I’ve been using Symlin for almost one month. I’ve managed to get the insulin/Symlin timing right (finally)! Here’s what I do:

  1. Take Symlin right before my first bite (only if my BG is higher than 80 mg/dl).
  2. Eat
  3. Program a dual wave bolus (I use the Omnipod) - 30% up front and 70% square over 30 minutes.

I have never dropped below 70 mg/dl after eating. I’ve also reduced my I:C ratio by 25%.

Hi Cheri,

Great post! Could you please explain more about how the combo bolus works? I’ve never used the feature and would like to start. I am have also started using the symlin as my sugars have been a little higher after meals. My last a1c was a 6.6 yesterday. Thanks.,