The Hydration Habit: Why Water Matters on GLP-1s
Let's talk about the unsexy truth of GLP-1 medications: dehydration is incredibly common —and it's the reason behind many of the side effects people complain about.
Headaches? Fatigue? Constipation? Dizziness? Most of these aren't from the medication directly—they're from not drinking enough water while your body's changing.
The good news: it's easy to fix.
Why GLP-1s Make You Dehydrated
Your GLP-1 medication does three things that affect hydration:
- Slows gastric emptying → Food AND water sit in your stomach longer
- Suppresses appetite → You forget to eat AND drink
- Often causes nausea → You deliberately drink less to avoid triggering it
The result? Most people on GLP-1s drink significantly less fluid than they need.
The Numbers You Need to Know
Standard recommendation: 64-80 ounces (8-10 cups) daily
GLP-1 adjusted recommendation: Aim for 80-96 ounces
Why more? Because your body processes fluids differently now.
Signs You're Dehydrated
Don't wait for thirst—that's a lagging indicator. Watch for:
- Dark yellow urine (should be pale yellow)
- Headaches, especially upon waking
- Constipation (water helps everything move)
- Fatigue or "brain fog"
- Dizziness when standing up
- Dry mouth or chapped lips
Smart Hydration Strategies
1. Front-Load Your Day
Drink 16-24 ounces within 30 minutes of waking—before coffee, before anything. Your body's been fasting for 8+ hours. It's thirsty.
2. Always Have Water Within Reach
Out of sight, out of mind. Keep a filled water bottle:
- On your desk
- In your car
- By your couch
- Next to your bed
3. Sip, Don't Chug
Remember that slowed gastric emptying? Chugging water can make you feel sloshy and uncomfortable. Small, frequent sips work better.
4. Set Gentle Reminders
Use your phone's alarm or a hydration app. Not to nag—just to pause and check in with yourself.
5. Make It Palatable
If plain water bores you:
- Add lemon, lime, or cucumber slices
- Drink sparkling water (can help with that "full" feeling)
- Try herbal teas (hot or iced, caffeine-free)
- Use sugar-free water enhancers (in moderation)
6. Eat Your Water
Many fruits and vegetables are 90%+ water:
- Cucumber (96% water)
- Watermelon (92%)
- Strawberries (91%)
- Cantaloupe (90%)
- Zucchini (95%)
A cup of cucumber slices is basically a cup of water with fiber.
The Electrolyte Question
Here's where it gets tricky. As you lose weight quickly, you lose electrolytes (sodium, potassium, magnesium). Pure water doesn't replace these.
When to add electrolytes:
- If you're drinking plenty of water but still feel "off"
- During hot weather or exercise
- If you're experiencing muscle cramps
Easy options:
- Pinch of sea salt in your water
- Sugar-free electrolyte powder
- Broth or bone broth (bonus: protein!)
Avoid: Sports drinks loaded with sugar and calories. Defeats the purpose.
What to Cut Back On
Some drinks actually dehydrate you more:
- Excess caffeine → Coffee and tea are fine in moderation, but 4+ cups daily works against you
- Alcohol → Dehydrating and can trigger nausea on GLP-1s
- Sugary drinks → Empty calories your body doesn't need
Not saying eliminate—just be strategic.
The Constipation Connection
Let's be real: constipation is the #1 digestive complaint on GLP-1s. Here's the hydration equation:
Dehydration = Hard stools = Constipation
Hydration = Softer stools = Regular movement
Water alone won't solve everything (fiber matters too), but it's the foundation. Without it, nothing works.
Practical Daily Routine
Morning:
- 16oz water upon waking
- Coffee or tea (count as ~4oz toward goal)
- 8oz water with any meds/supplements
Afternoon:
- 8oz before lunch
- Water with lunch
- 8oz mid-afternoon
Evening:
- 8oz before dinner
- Water with dinner
- Optional: herbal tea before bed
Total: ~64-80oz from intentional drinking, plus water from food = goal achieved.
Tracking Without the Hassle
Don't obsess over counting ounces. Use the urine color test:
- Pale yellow/straw → Well hydrated ✅
- Bright yellow → Drink more water soon
- Dark yellow/amber → Dehydrated, drink now
- Clear → You're probably overdoing it
Simple. Effective. No app required.
When to Talk to Your Doctor
While most dehydration is easily managed at home, seek medical advice if:
- You can't keep fluids down
- Severe dizziness or fainting
- No urination for 12+ hours
- Signs of heat stroke in warm weather
The Bottom Line
Water isn't glamorous, but it's the unsung hero of your GLP-1 experience. Prioritize hydration and many "side effects" simply disappear.
Your action item: Fill a water bottle right now. Place it where you'll see it. Take three sips. Congratulations—you're already doing better than yesterday.
Stay hydrated, stay healthy. Questions? Reach out on Twitter or subscribe to our weekly tips below.