“What should blood sugar levels be in the evening?”

Fasting blood sugars should be between 80-120. Pre-meals/3 hours post-meal or bedtime/evening blood sugars should be 140-160, anything >180 is high.

Ali A. Achira, MD

Around 130

It depends on his treatment. If he is taking long acting insulin like lantus, Tresiba or Basaglar, the idea is to have stable blood sugars overnight, vgr. 120 at bedtime and around 120 when he wakes up. If his blood sugar goes low overnight means that he needs less insulin. The best that you can do is discuss his treatment with his endocrinologist as soon as possible.

Fasting blood sugar in the morning in most people without diabetes is between 70 & 100. After meals it may go up to 125 in non-diabetics-AM, PM or evening. So BS in the evening after supper should be between 100 & 125. It gradually falls lower during the late eve or night so the fasting in the morning is lower. You did not say why your sons BS is low. I assume from this he does not have diabetes. If he does, the low BS is easy to fix-simply decrease his diabetes meds, If he does not have diabetes, but has hypoglycemia he needs a work up to find out why. This can be due to a problem of the liver, a tumor of the beta cells of the pancreas, a failure of the beta cells of the pancreas to communicate & coordinate insulin secretion, failure of the pancreas to produce glucagon (a hormone that raises BS) or a failure of the liver to respond to glucagon & release stored sugar. He needs to see a Dr. familiar with hypoglycemia & find out the cause of his hypoglycemia since most causes are treatable & continued hypoglycemia can cause brain damage.