Diabetes Self-Management Blog

Do you wake up with a blood glucose level that’s higher than when you went to bed? You might wonder how this could be. Is this “dawn phenomenon” serious, and what can you do about it?

Our reader Mishelle commented here, “I don’t eat [much] during the day. [I take metformin morning and night.] My blood sugar is still too high in the morning…sometimes 125–140ish.”

How can Mishelle’s glucose levels go up if she didn’t eat anything? She probably has a mild case of dawn phenomenon. Her glucose is going up from sources other than digested food. Some of it is produced by the liver from stored starch and fatty acids. Livers that produce too much glucose are one of the main ways diabetes causes high blood glucose levels. Other organs also produce small amounts of glucose. This is called “gluconeogenesis” for you science freaks out there.

Organs do this to keep blood glucose from going too low at night or other times of not eating. From about 2 AM to 8 AM, most people’s bodies produce hormones, including cortisol, glucagon, and epinephrine. All these hormones increase insulin resistance and tell the liver to make more glucose. The idea is to get you enough glucose to get out of bed and start the day. The whole process is apparently started by growth hormones.

Everyone has a dawn phenomenon. Otherwise they’d be too weak to get breakfast. But in people without diabetes, insulin levels also increase to handle the extra glucose. People with diabetes can’t increase insulin levels that much, so their early morning blood glucose levels can rise dramatically.

Experts disagree on how many people have a dawn phenomenon. Estimates range from 3% to 50% of Type 2s and from 25% to 50% of Type 1s.

Is dawn phenomenon a serious problem?
It can be serious. According to the American Diabetes Association, “Some people with dawn phenomenon find that their glucose continues to rise until they eat in the morning. For others, levels will settle down a few hours after waking, regardless of whether or not they eat.”

Either way, that can be a long time to spend with elevated blood glucose levels. For some people, like Mishelle, the highs aren’t that dangerous. Others go much higher.

According to columnist Wil Dubois, the higher your A1C, the more likely you are to have a significant dawn phenomenon. It could be that spending a number of hours each morning out of control is having a significant effect on your overall control.

So it’s worth trying to get dawn phenomenon under control. How can you do that? You have to figure out what is triggering it and then try some possible solutions.

Some people have high glucose levels in the morning because their medicines wear off overnight. This could be true of medicines like insulin, sulfonylureas, and metformin. If you are taking any long-acting medicine, consider asking your doctor about changing meds, doses, or times. Our reader Mishelle might benefit from taking her metformin later in the evening, for example. Metformin is good at keeping a lid on the liver.

In some cases, medicine can be too strong. If your glucose goes too low in the night, you could have a rebound high in the morning. This is called the Somogyi effect. Wil Dubois says

If you are waking up high and are suffering pounding headaches, or find your sheets sweat-soaked, the odds are you are having lows in your sleep…You need to visit with your doctor about taking less meds.

According to Dubois, the new insulins are much less likely to cause a Somogyi reaction. But because of cost, people are going back to NPH insulin. NPH is cheaper, shorter-acting, and more likely to cause a low, leading to a rebound high in the morning.

What can you do to reduce or eliminate dawn phenomenon? Diabetes blogger David Mendosa says many things work for some people and not for others. People report blocking the dawn phenomenon with a green apple or a cornstarch product — here’s one Mendosa mentions — at bedtime. These might keep a low, steady, level of glucose coming and might prevent nighttime lows and highs.

Not eating at all after 7 PM probably won’t help. It will set you up for a Somogyi rebound. A protein snack like nuts or cheese at bedtime might help. But you will have to experiment and keep records for yourself. Everybody is different.

Mayo Clinic doctor Maria Collazo-Clavell, MD, says avoid carbs at bedtime. She also says an insulin pump can help a lot. You can program it in advance to increase your insulin when the dawn phenomenon starts to kick in. You might have to check a few middle-of-the-night levels to find out when the phenomenon starts for you, or if you are going too low.

Alcohol at bedtime is another choice. A glass or two of wine or spirits might keep your liver too busy to bother pumping out extra glucose in the morning. Alcohol also helps some people get to sleep.

Unfortunately, alcohol often wakes you up again way too soon. And there is a risk of going low AFTER breakfast if you drank the night before. (Editor’s note: Because of these, and other, risks of alcohol, it is not recommended that you begin drinking just to combat the dawn phenomenon.)

Vinegar might be the best choice. You can take tablets or a liquid. Most people I’ve read commenting on various sites needed 4–6 vinegar tablets at bedtime to avoid a morning spike. There’s not much research, though vinegar has been shown to reduce insulin resistance.

Hope this helps, Mishelle. Readers, do you have other ideas? What have been your experiences with dawn phenomenon?


  1. excellent comprehensive article and covering many aspects of Dawn Phen. Thank you.

    Posted by jim snell |
  2. Thanks for this. Why I have to be an exception to what this article http://www.medscape.com/viewarticle/814001 states “The one medication that does prevent this is insulin.” is still puzzling for me. Until I split my dose of Lantus, I would have continued problems with the dawn phenomenon. Shortly after splitting my dose, I no longer had this problem.

    Thanks again!

    Posted by Bob Fenton |
  3. I didn’t know 125 blood sugar in AM was too high?

    Posted by Ms Mercer Ervin |
  4. Ms. Ervin,

    A fasting sugar of 125 mg/dl is prediabetic. Mishelle wants hers to be lower, and lower is better. But its her choice and your choice what goals to shoot for.

    Posted by David Spero RN |
  5. I’m interested in what Bob had to say about splitting his insulin dose. I’ve heard people who take larger doses of Lantus (or other long-acting insulin) getting better results splitting it into two doses, 12 hours apart.

    I’m up to 50 units of Lantus and am curious about the pros and cons of two 25 unit doses vs. on 50 unit dose.

    Perhaps an idea for an article or blog entry?

    Posted by Joe |
  6. I have experiennced higher than expected/accounted for readings on awakening aftter a “busy” nightmare. One in particular was a dream that I was filing things and was like the sweeper in Sorcerer’s Apporentice cThe more I filed — the more there was to be filed. (I have been retired from office work for 20 plus years!)

    Posted by Pat Kass |
  7. I have had the “Dawn Phenomenon” for years. My diabetes specialist could not add or auggest any solutions, so I took it upon myself to split my Lantus dosage to 50% in the morning and 50% at bedtime. I now wake up with a much improved glucose reading but, on occasion, it is off the charts! I cannot figure out why….In addition, I sometime wake up in the middle of the night to go to the bathroom and my tee shirt is wet. I suppose my glucose went too low but it did not waken me. I have had Diabetes since 1991 and I am still learning each day about the struggles to maintain an acceptable level reading.

    Posted by Mr. Gregg |
  8. If I did have that problem, my doctor wouldn’t believe me. She’d just accuse me of carb loading or something…a split of Lantus does seem to be effective though.

    Posted by Terri |
  9. As a 30 year type 2 and having dealt with an extremely nasty dawn effect and liver dumping problems of my body and with my Doctor’s assistance and watching extensive data on a cgms; I have the following comments:

    a) at 3:00 am, my body starts the wakeup sequence and starts signalling the liver to add glucose.

    b) liver uses reverse signaling based on the presence of insulin in blood to control how much glucose to add and when to stop doing that. So if you are short insulin, oh boy, look out liver assumes you are short glucose and really loads up body - never mind you don’t need much or any glucose.

    c) I have watched comments from the pumper crowd and those instructed to add extra insulin and if their liver is listening to signalling properly; adding basil insulin or extra insulin during these times; liver is determined to hammer up glucose seems to stop, moderate, arrest that.

    d) for those of us -, I believe who have compromised liver signalling ( and assumed due to extra fat inside liver (not belly/body fat), metformin was the only option that at sufficient dose in blood arrests that nonsense and instructs the liver to stop dumping in excess glucose.

    I also found that metformin was very helpful for stalling out rare but curious unnecessary liver dumps at normal times.

    e)after a number of years of restricted diet, low carb 1200 cal diet, 1.5 mile daily exercise and regular metformin doses; I have discovered that my liver is listening better to body insulin and does of insulin late at night and that now also helps keep blood glucose thru night under better control. The beauty of the pumps is that one can instruct the computer when to add insulin and how much and fine tune the liver’s behavior.

    f) adding snacks late at night , I do not due but suspect that eating triggers a bolus add of insulin from a working/partly working pancreas to add insulin and that helps arrest liver tricks/misfire.

    It has taken the last 5 years to walk, try, experiment and finally arrest this nasty dawn phen which frankly is one nasty customer.

    David: Special thanks for shining a light and key column on this nasty problem that underscores the role of the liver and its buffer and horsepower to sugar up the body!

    Posted by jim snell |
  10. For those of us who have the horrid side effects from Metformin, taking it later without a meal would make those effects worse. I have to have a snack with my HS meds but haven’t figured out the best one.

    Posted by Ferne |
  11. I too was having high numbers in the A.M… 125-135 and sometimes 140.. I read about Vinegar in an article in “Diabetes Management”, about Vinegar , So I tried it, You will not believe how great it is! now you have to be careful if you take too much you will really lose weight, being a thin person, this was somethng I didn’t want to happen,, but I over came my fear and being who I am, I conquered it.My numbers went from 138 , 140 to believe this or not,, to 125,121,111,100,, and so forth. I am smart enough to realize as I was watching these numbers when to cut back on the vinegar..but not stopping it altogether,, My A1C’s went from 6.8 to a glorified 6.5.. Now it takes some getting used to the vinegar, I used White Vinegar as the Apple Cider made me shutter.. Just take 1 tables spoon of Vinegar in 1/2 glass of water, take it after you have eaten, but not at the same time as you take your pills. And see what happens..
    Good Luck,

    Posted by RUTH A |
  12. I am allergic to Metformin and choose to regulate blood sugar at this point with lifestyle changes of diet, exercise, weight loss, stress reduction and supplements. Dawn phenomena remains my only consistent blood sugar issue. Through personal research, I have tried all of the suggestions noted in the excellent article. There were very little information out there when I first tackled my DP. Vinegar did not work for me, but better sleep habits, lowering stress, meditation and nighttime snacks have lowered my morning spike to a point I no longer worry about it. This was a long process of testing what worked for me, and lots of finger pricks, but worth the effort.

    Here’s what helped me without question:
    Do not eat a heavy evening meal.
    After dinner, I eat a small snack at 9PM (I usually eat string cheese with a few almonds or hummus with a high fiber cracker or sweet potato corn chips with guacamole. No more than six chips or three crackers. I think eating the combination of good fats and protein, or good carbs and protein work best for this evening snack)
    Eat another snack right before bed. I usually eat a medium sized apple (good carb)but have also had half of a low carb snack bar(also worked for me). I usually eat my apple with a sugar free nut butter spread (protein). It does not have to be a green apple, but I do choose tart varieties.
    If I wake in the night I drink water and eat 4-5 almonds or walnuts really taking my time to chew them to a paste. (to avoid digestive issues) The middle of the night nuts usually give me my lowest dawn readings. My blood sugar levels do best when I eat every five hours throughout the day, (3 light meals and three small snacks) so makes sense to me this would be best at night as well.)
    In addition–I try to be faithful in getting good sleep at regular hours, wear a Breathe Easy strip to get better levels of oxygen if I am at all stuffy and have an air filter fan running at night.

    Stress (a cortisol producer) usually makes the dawn number higher for me, so I meditate and have worked to de-stress my life. Exercise lowers my blood sugar, so I do weights and a rower. But never for more than half an hour. Muscles gets stressed when you exercise too long, and pump out more of the hormones that creates dawn phenomena.

    I also take vitamin and fiber supplements: a good multivitamin, extra D, extra C, Black current oil, CoQ10, cinnamon and turmeric

    I’ve lost 50 pounds. My fasting blood sugar reading was 350 on diabetes diagnosis day a year ago. My three month average was 10.5. It is now 6.4. (Doctors should know that a fasting blood sugar reading is always going to be higher for a patient with dawn phenomena, but they usually don’t factor that in.)
    My dawn phenomena readings have gone from average of 250 to 124. As overall blood sugar readings go down the dawn number goes down, too, so I have focused on getting the overall readings down. Good luck to all who are working to get dawn phenomena under control.

    Posted by Donna G |
  13. Donna G - Glad I found this page. I am diagnosed just over a month and my morning readings can be 160-180. I am going to try the vinegar tonight as well as leaving some nuts by my bed as chances are good I will wake up at some time.

    Thank you - sure hope it helps

    Posted by Joanne |
  14. oh sorry it was Ruth with the vinegar :-) I will see what works for me!

    Posted by Joanne |
  15. Hi, from Greece, to everyone.
    It’s 20 days now since I left the hospital with a type 1 diagnosis.
    My readings before entering were 320 fast & 580 at about 9 pm.
    Now I do 3 fast acting inj. before meals and 1 long acting at 5 to 6 pm.
    Before bed I eat 2 small burley rusks, 1 low fat (2%) yogurt and 2 nuts, total 30 gr of carbons.
    My morning reading today was 111 mg/DL.
    I’ll inform you after a couple of weeks for how is going.
    Good to know you are all there.

    Posted by Lenny |
  16. I have diagnosed with diabetes 3 months ago my blood glucose was 570 and I have also diagnosed 6 years ago with hyperthyroidism I never loose weight on the contrary I am always gaining weight and I am always waking up have this spike of vlood sugar ( 140 to 180 )
    Please help and guide me what to do ro low my blood sugar and also loosing weight to get healthier

    Posted by lily |
  17. Lily, tho my bg was not up as high as yours, and I am only on oral medication, I too had the same problem of fluctating bg levels and constant weight gain. My Dr told me about a book The Blood Sugar Solution 10 Day Detox by Dr Mark Hyman, there is also companion cookbook. Changing my diet completely seems to be what is helping me.

    Posted by Sharon |
  18. My theory is sleeping habits are to blame. Less sleep mean more hormones produced to wake a person in the morning. I have notice more of a problem when I have had issues sleeping the night before. Adjusting your insuling will help some but if you have a steady relese of the hormones telling your liver to release glucose then you can never know how much to take…

    Posted by Bill |

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