Caffeine
Caffeine and Blood Sugar: How to Tell Jitters From a Low
Caffeine and blood sugar can be hard to separate by feel, because both can cause shaky hands and a fast heartbeat. The FDA cites up to 400 mg of caffeine a day as an amount not generally linked to harm in healthy adults. If you have diabetes, check a meter reading before you guess.
Written by the Glyco Defender facts deskUpdated · 4 min read
The link01
How does caffeine affect blood sugar?
Caffeine and blood sugar are linked in ways that vary by person, and the sources we cite do not settle one rule, so your own meter is the best guide.
What we can say with sources is about the feel of caffeine. The FDA lists a fast heartbeat, jitters, anxiety and poor sleep among its effects (FDA, Caffeine: how much is too much?).
Those effects overlap with the warning signs of a low, which is why people mix them up. A shaky morning after a strong coffee may not be your blood sugar at all. Write down what you drank, when, and how you felt, then compare it with a meter reading.
The reverse also holds. A real low can look like too much coffee, so do not dismiss shaking when you have diabetes or take medicine that can cause lows.
How much02
How much caffeine is too much?
For most healthy adults, up to 400 mg of caffeine a day is cited by the FDA as an amount not generally associated with negative effects (FDA, Caffeine: how much is too much?). That is about two to three 12-ounce cups of coffee.
People who are sensitive, pregnant or on certain medicines may need much less. The same FDA page notes that too much caffeine can bring upset stomach, nausea and headache as well (FDA, Caffeine: how much is too much?). Ask your doctor what is right for you.
| Sign | Caffeine | Low blood sugar |
|---|---|---|
| Fast heartbeat | Yes (FDA, Caffeine: how much is too much?) | Yes (NIDDK, Low Blood Glucose) |
| Shakiness, jitters | Yes (FDA, Caffeine: how much is too much?) | Yes (NIDDK, Low Blood Glucose) |
| Sweating | Not listed by the FDA | Yes (NIDDK, Low Blood Glucose) |
| Hunger, confusion | Not listed by the FDA | Yes (NIDDK, Low Blood Glucose) |
| Trouble sleeping | Yes (FDA, Caffeine: how much is too much?) | Not listed |
Know the signs03
How do you tell caffeine jitters from low blood sugar?
You tell them apart by checking the number: a true low reads under 70 mg/dL for many people with diabetes (NIDDK, Low Blood Glucose), and a normal reading points toward caffeine or another cause.
If you cannot check, treat a suspected low first, then talk to your doctor. Treating wrongly costs little, and missing a low costs more. Use the 15-15 steps from the chart below, and tell your doctor if lows repeat.
- Shaky or jitteryTrembling hands, feeling nervous
- Sweaty, chillsClammy skin out of nowhere
- Hungry, nauseousSudden strong hunger
- Dizzy, confusedTrouble thinking or speaking clearly
- Fast heartbeatPounding or racing pulse
15-15For many people with diabetes, a low is under 70 mg/dL. Take 15-20 g of fast carbohydrate (juice, glucose tablets) and check again 15 minutes later.
Call 911If a person with a low passes out, has a seizure or cannot swallow safely. Someone who is unconscious should not be given food or drink.
Signs and steps from NIDDK (NIDDK, Low Blood Glucose). Insulin, sulfonylureas and meglitinides can bring on lows, and supplements may add to that (ADA, Vitamins & Supplements).
Hunger and confusion lean toward a low. Restless sleep and a racing mind lean toward caffeine. The sleep and blood sugar post covers the night side.
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Should you ask a doctor about caffeine and supplements?
Yes, ask a doctor if you take diabetes medicine, have heart rhythm concerns, sleep poorly or are pregnant, since caffeine adds to the load.
Keep taking your prescribed medicine. Bring a list of every coffee, tea and supplement to the visit. The ingredients page and the who it is for page list the plants with caffeine.
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Glyco Defender is a dietary supplement, not a treatment. Ask your doctor or pharmacist first if you use insulin, a sulfonylurea or another glucose-lowering drug, a blood thinner, blood pressure or heart-rhythm medicine, an antidepressant or thyroid medicine. Chromium, gymnema and ginseng may add to diabetes medicines and cause lows; guarana and green tea add caffeine. Keep taking prescribed medicine. See side effects and interactions.
FAQ06
Glyco Defender questions people ask
Does coffee raise blood sugar?
Possibly in some people, but the sources we cite do not give a rule, so check your own readings. The FDA's concern is with jitters, heart rate and sleep (FDA, Caffeine: how much is too much?). If you have diabetes, test before and after coffee for a few days and show your doctor.
Is green tea caffeine different from coffee caffeine?
It is the same compound, and the amount per cup varies by brew and leaf. NCCIH notes that green tea contains caffeine (NCCIH, Green Tea). Add tea and coffee together when counting toward the 400 mg guide.
Can guarana cause shakiness?
Yes, guarana seeds contain caffeine, and high doses can cause heartbeat changes and high blood pressure (MSKCC, Guarana). If a product with guarana makes you shaky, stop and talk to your doctor, and check your meter if you have diabetes.
Who wrote this07
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