Diabetes is one of the most common metabolic disorders, affecting millions of people worldwide. There are many signs and symptoms, including headaches. While a headache does not necessarily mean a change in blood glucose level has occurred, it can be a warning sign.

Headaches are often seen in insulin-dependent diabetic patients. Changes in blood sugar levels due to insulin, most notably reduced sugar levels, are associated with this symptom.

Types of Headaches

As different people have different thresholds for pain, what constitutes a severe headache will vary. A headache is considered to be severe when a person loses their ability to function normally.

Before we connect headaches to diabetes, it is essential to understand the different types of headaches.


A primary headache is a condition where the brain sends pain impulses directly to the blood vessels, nerves, and muscles in the cervical region. The most common examples are tension and migraine headaches.


A secondary headache develops due to other conditions such as infection and metabolic disorder. Diabetic headaches are classified as secondary headaches, as the primary cause of pain is not the brain.

Other conditions that cause secondary headaches include injury, tumours, endocrine disorders, and fever.

Secondary headaches due to diabetes indicate that a person’s blood sugar levels are fluctuating more frequently. You can have a headache due to hyperglycemia or hypoglycemia. Proper blood sugar regulation often eliminates headaches caused by diabetes. Pain medication can also be utilized.

Hyperglycemia and Headache

Not everyone with hyperglycemia develops headaches. If your blood glucose level is more than 200 milligrams per deciliter (mg/dL), this problematic and symptoms may take several days to develop. Headache is a primary symptom of hyperglycemia, alongside increased thirst, dehydration, increased appetite, blurred vision and fatigue.

Hypoglycemia and Headache

Hypoglycemia can occur due to a high dosage of insulin or due to not eating carbohydrates after receiving insulin. While hyperglycemia causes a delayed headache, headache due to hypoglycemia is swift. When a person’s blood glucose levels reach less than 70 milligrams per deciliter (mg/dL), there is a sudden drop in the brain cells’ energy source, which causes specific physiological changes in the brain’s neurons. This results in the sudden onset of a headache.

Headache due to hypoglycemia often causes severe distress.

Other associated symptoms include:

  • sudden hunger,
  • fatigue,
  • weakness
  • dizziness.


Diabetes often causes secondary headaches. To reduce their occurrence, consult with your physician on a regular basis, monitor your blood glucose levels and eat a healthy, low-carbohydrate diet.

Doctor’s Recommendation

If you have diabetes and experience frequent headaches, it’s important to consult your doctor to adjust your treatment plan. Seek medical attention if your headaches are severe, worsening despite pain relief, or occur along with symptoms like throbbing pain in the front or side of your head, fever, nausea, vomiting, or sensitivity to light and sound. Go to the emergency room if you have headaches within five days of a head injury, severe pain, blurred vision, or difficulty walking, speaking, or remembering.

Disclaimer: Please note that the contents of this community article are strictly for informational purposes and should not be considered as medical advice. This article, and other community articles, are not written or reviewed for medical validity by Canadian Insulin or its staff. All views and opinions expressed by the contributing authors are not endorsed by Canadian Insulin. Always consult a medical professional for medical advice, diagnosis, and treatment.