Like Clockwork: Low BG at 4am

Hi Everyone,

I am a (mostly) happy Dexcom Platinum user, but am still having consistent low BGs at 4am almost every night. Even if I go to bed with BG of 170, my CGM wakes me up for the AM low. I have tried changing when I take my Lantus (long-acting insulin) from 10pm to 5pm (it is slightly better), as well as switching my workout schedule around, going high at bedtime, etc. and nothing has consistently worked!

Has anyone else experienced this? Perhaps its hormonal or has to do with the sleep cycle? Any suggestions or advice would be most appreciated, as I miss getting a full night's sleep!


Have you tried splitting your lantus dose? I read about people doing that here, and despite my doc not recommending it, it worked for me. Half at bedtime, half 12 hours later. Because of insulin on board, and your own needs, you might want to stagger or deviate. At any rate, research past discussions about it and see what you think. Good luck!

Mine does exactly the same at exactly the same time - 4am on the dot. =) This is where an insulin pump is worth it's weight in gold, because you can slash your basal rate right when it starts to drop, then bring it back up when you figure out what time your BG is rising.

Also, I don't know if you're a red wine drinker, but when I have red wine (strangely not white) with dinner or after dinner, it really exacerbates the 4am drop.

Think about a pump. I was a late convert, but it's a game changer. Good luck!

I agree with Elaine: splitting the Lantus into two portions may help. See

When I used to take 32 units of lantus at night I would have a hypo just about every single night. Although doctors are led to believe lantus is a 24 hour "peakless" insulin,for many people it does have a very distinct peak and does not last 24 hours. The hypo you are getting may be due to the lantus peaking. You may want to split your lantus dose or switch to levemir which doesn't seem to peak like lantus does. At least that is my experience with both types of long acting insulin. I eventually decided to go the pump route and am really happy with that decision.

Thanks so much for your replies, kb viola, elaine, and Bill Quick! Splitting the dose is a great suggestion-- I'm starting tonight! If all else fails, it is nice to know that being on a pump eliminates this issue. I'm still relatively new to all of this (I was diagnosed six months ago), so I've been trying to simplify and keep costs down.

Thanks, Clare-- I really appreciate your advice! Looking up levemir now! :)

My endo has a fridge full of samples. She was more than happy to give me a levemir pen to try out. It does need to be split dosed which is no big deal when using a pen.

This where a CGM is worth its weight in gold. Without it you might not know
you were having hypos every night if the low didn't wake you up. It's not good to have hypos that often.

For myself, I had real trouble balancing daytime and night time basal using Lantus. My nighttime requirements were much higher than daytime, so either I would be low during the afternoon or too high overnight. I tried splitting the dose and it didn't work for me.

I eventually went to a pump. With a pump, if you see periodic lows, you can start lowering your basal rate 2 hours before (say 2 AM if the low is at 4AM) and then adjust it back up later in the night if you have a problem with dawn phenomenon.

Some people have been more successful in adjustments like this with Levemir (shorter acting than Lantus, so usually 2 shots a day), and I might try that if I were forced to go off of the pump and back to MDI.

P.S. I went on the pump about 9 or 10 months after diagnosis, after I was comfortable with carb counting and MDI.

Levemir does seem like a good option, if splitting the Lantus dose doesn't work out. I'm sure I'll end up on a pump eventually, but other than this annoying regular low I'm in pretty good control. Thanks for your response!

My daughter's (12 y.o.) BG also takes a dive around 4 a.m. (when most adolescents experience their Somogyi phenomena and go high). Thankfully, she's on a pump now, so I just keep adjusting her basal dose around that time.

The problems you have are exactly why I also changed my control to using a pump instead of MDI. Massive difference in control! Brought my A1c down from 8.0 to 6.0 range too.

This is the exact reason that my endo is trying to get me on a pump -- though for me, it's 4:30am, even when I split my Lantus dose, and even when I take Levemir. I have also tried varying the time of my basal doses, taking uneven split doses, etc. Each change resulted in changes in the TIME of the lows, but did not prevent them -- and, after a few days, the lows slipped back into the same time slot, regardless of the change I made. The real thing at play is apparently my internal bio-clock. I'm waiting on insurance, but hope that with a pump I can make the necessary adjustments to stop this pattern once and for all.

I really appreciate everyone's responses! I tried splitting my dose of Lantus and did not go low last night- so great! While I know this could change and it takes a week or so to fully acclimate, I'm already feeling better rested.

I changed endo's and the first thing he did was reduce my Levemir dose and he had me take it at the noon meal with my short acting. This has really helped, I'm very insulin sensitive as he puts it and my past doctor had had me double the dose and in the evening meal. This might work for you if on your Lantus.