A patient once described it to me with one word: desert.
Not thirsty. Not dehydrated. A desert.
He'd been drinking water all morning. His tongue still stuck softly to the roof of his mouth every time he swallowed. He was sure he wasn't drinking enough. He was wrong.
What he had was type 2 diabetes, recently diagnosed. And the thing most people miss: dry mouth in diabetes isn't thirst. It's a different signal, with a different mechanism — and water alone won't fix it.
Two kinds of dry
There are two kinds of dry mouth.
One you can drink your way out of. The other you can't.
When blood sugar runs high for days at a time, something quietly inefficient happens. Your kidneys, brilliant filters that they are, start dumping the extra sugar into your urine — and water comes along for the ride. That's the famous "always in the bathroom" sign of diabetes. You're losing fluid faster than you realise.
Your salivary glands notice immediately. They're picky little organs: the moment your body even mildly under-hydrates, they slow down. They're one of the first systems your body decides to ration.
So you drink, and the water leaves before the glands catch up. You drink more, and it happens again. Your mouth stays dry because the problem isn't how much water you swallow — it's the tap that's been turned down upstream.
You're not thirsty. You're running a fluid leak your kidneys are creating and a saliva problem your glands are responding to. More water alone won't close the gap.
There's a quieter problem too. Saliva isn't just lubrication. It's your mouth's natural cleaner — protecting teeth, buffering acid after meals, keeping bacteria in check. Less saliva means more cavities, more gum trouble, more bad breath that mouthwash won't shift. In diabetes, gum disease is two to three times more common than in everyone else. The dryness travels with company.
What to try this week
I can't tell you what's right for your specific case — the doctor who knows you can. But there's a small pattern that works for most people, and none of it needs a prescription:
- Sip, don't gulp. Small amounts often, instead of big glasses now and then. Your kidneys can't hold onto a flood; they work better with a steady drip.
- Chew sugar-free. A piece of gum or a lozenge with xylitol after meals. It stimulates the saliva you still have, and xylitol on its own protects against tooth decay. Twice a day is enough.
- Brush twice, floss once, with fluoride. Standard advice, made non-negotiable by the dryness. Less saliva means more work for your toothbrush.
- Tell your dentist. If you have diabetes and your dentist hasn't asked about your blood sugar, mention it. Six-monthly check-ups stop being optional when your mouth is dry.
None of this fixes the underlying issue if your blood sugar is drifting. But it buys comfort, protects your teeth, and gives you time to talk to your doctor properly.
The small art of noticing
Dry mouth is a small, quiet symptom. It doesn't put you in hospital. It doesn't show up on routine blood tests. That's exactly why it's worth paying attention to.
The people who do best with long conditions — over years, not weeks — are the ones who learn to notice. Not panic. Not catastrophise. Just notice. The slightly different feel of the morning. The new line under the eyes. The dryness at 11am that wasn't there last year.
They take it to their doctor, calmly, with one question: "Has anything changed in my numbers, or is this just me?"
That's the whole project of this journal, in a sentence.
Curiosity first. — Dr. Brugal