Treating a Low: The 15-15 Rule
Reviewed by CDE Mehandi Sharma · Updated
Low blood sugar, or hypoglycemia, is generally a reading below 70 mg/dL. It needs treating straight away, and the method is simple enough to memorise.
The early signs are shakiness, sudden hunger, sweating, a fast heartbeat, dizziness, headache, tiredness or trouble seeing clearly. People often describe feeling suddenly and unusually unwell. At night it can show up as nightmares, sweating, or waking confused.
The 15-15 rule
- Take 15 to 20 grams of fast-acting carbohydrate straight away.
- Wait 15 minutes.
- Check your blood sugar again.
- If it is still below 70 mg/dL, repeat.
Fifteen grams is roughly three or four glucose tablets, three teaspoons of sugar or glucose powder in water, or half a cup of regular fruit juice or a regular soft drink.
What not to reach for: chocolate, biscuits, milk-based sweets or a full meal. The fat in them slows absorption down, which is the opposite of what you need in that moment.
Once your reading has recovered, if your next meal is more than an hour away, eat a small snack with some protein in it so you do not drift low again.