By Ethan BrooksUpdated November 2026
Energy gels and diabetes can work together on long runs, but only if you plan the timing, check your blood glucose before and during exercise, and carry a fast-acting low-glucose treatment. This guide walks you through how to decide whether a gel fits your plan, how to test and adjust your intake, and how to prepare for race day. It is general training information, not medical advice, so please coordinate changes with your diabetes care team.
Why Energy Gels and Diabetes Need Extra Planning
Energy gels are concentrated carbohydrate, usually 20 to 25 grams per packet, designed to be absorbed quickly during exercise. For a runner without diabetes, that rapid carbohydrate supply helps keep blood glucose steady after the first hour of effort. For a runner with diabetes, the same carbohydrate hit can push glucose too high, or, if insulin is on board, drop it too low. The challenge is that exercise itself changes how your body handles insulin and glucose, sometimes for hours afterward.
Shopping for one? See our guide: Honey Stinger Energy Gels Review (2026): Pros and Cons.
Two things drive most of the variability. First, active muscles pull glucose from the blood without much insulin, which can cause lows during or after a run. Second, stress hormones released during hard efforts, especially in races, can raise glucose. Your gel plan has to account for both.
Step 1: Talk With Your Diabetes Care Team First
Before you use gels during training, review your plan with your endocrinologist, diabetes educator, or primary care provider. Ask specifically about insulin adjustments on run days, the carbohydrate amount you should take per hour, and which glucose targets to aim for before, during, and after exercise. Your clinician may recommend changes to basal or bolus insulin, a pre-run snack, or a different delivery method for carbohydrate.
Bring a training log to that appointment. Record run length, pace or effort, what you ate, your insulin doses, and your glucose readings. A month of logs gives your team real data to work from.
Step 2: Establish Your Baseline With Glucose Testing
You need to know how your body responds to running before you add gels. Plan a few runs at a comfortable easy pace, without gels, and test your glucose before you start, at intervals during the run, and again 30 to 60 minutes after you finish.
- Before the run: test 10 to 15 minutes before you leave.
- During the run: test every 20 to 30 minutes on runs longer than 60 minutes, or use a continuous glucose monitor if you have one.
- After the run: test at 30 minutes and again at 60 minutes, since delayed lows are common.
Write down the numbers and how you felt. Patterns will show up quickly, such as a steady drop around the 45-minute mark or a spike after intense intervals.
Setting a Starting Glucose Range
Many diabetes education resources suggest starting a run with glucose in a moderate range rather than at the high or low end. If your reading is low before you start, eat a small carbohydrate snack and retest before heading out. If it is very high, check for ketones if your clinician has told you to, and discuss with your team whether it is safe to exercise that day. Your own targets should come from your care team.
Step 3: Decide When a Gel Makes Sense
Gels are most useful on efforts longer than about 60 to 75 minutes, where your glucose is likely to fall and your usual snacks no longer keep up. They are less useful on short runs, where you might not need extra carbohydrate at all. For general timing principles, see When to Take Energy Gels: A Marathoner's Timing Guide, then adapt them to your glucose data.
Timing Your First Gel
Many runners without diabetes take their first gel around 45 to 60 minutes in. For a runner with diabetes, the right time depends on your baseline data. If your glucose drops steadily from the start, you may need to take a small amount of carbohydrate earlier, perhaps 15 to 20 minutes into a run, and test again soon after. Your team can help you set this threshold.
Step 4: Match Gel Carbohydrate to Your Glucose Response
A common starting framework for hypoglycemia prevention during exercise is a small, repeated carbohydrate intake rather than one large dose. A single gel is about 20 to 25 grams of carbohydrate, so one packet at a time, followed by a retest, gives you control. Avoid taking several gels at once.
| Glucose trend during run | Typical response to discuss with your team |
|---|---|
| Dropping steadily, still above your low threshold | Take one gel, retest in 15 to 20 minutes |
| Already at or near your low threshold | Use a fast-acting treatment right away, then test again |
| Stable or rising | Hold off on gels, keep monitoring |
| Rising sharply during hard intervals | Slow down, hydrate, and recheck before adding carbohydrate |
Use this table only as a discussion starter. Your specific thresholds and doses should be set with your clinician.
Step 5: Choose the Right Gel for Your Needs
Not all gels behave the same way. Some are formulated with a mix of glucose and fructose, which can be absorbed by different pathways. Others are caffeinated, and caffeine can influence glucose and sleep patterns, so check with your team before using one. Many runners with diabetes prefer gels with a simple ingredient list, consistent carbohydrate content on the label, and no unexpected additives. For a broader look at options, read Running Energy Gels Comparison: 7 Factors to Compare Before You Buy.
Low-carbohydrate gels are sometimes marketed to people following keto or low-carb eating plans. Those products may not provide enough fast carbohydrate to treat a low, so do not rely on them for hypoglycemia. See Top 5 Best Low Carb Energy Gels Compared for Keto Runners for context, but keep a standard-carbohydrate option on hand.
Step 6: Carry a Low-Glucose Treatment at All Times
Whether or not you use gels, always carry a fast-acting source of glucose you can reach without stopping. Gels are convenient, but they can be slow to absorb if your stomach is upset, and they can be hard to swallow when you are shaky or confused from a low. Glucose tablets, a small juice box, or hard candy with a known carbohydrate count are common alternatives. Keep one on your person during every run.
Tell a running partner or race-day volunteer about your diabetes and what symptoms to watch for. Consider wearing medical identification.
Step 7: Plan Race-Day Fueling
Race conditions raise the stakes. Adrenaline, heat, crowds, and tapering can all change your glucose. Practice your full race-day plan in at least two long training runs: the same breakfast, the same pre-race glucose target, the same gel schedule, and the same insulin adjustment. Note where aid stations fall on the course so you know when gels are available if you do not carry your own.
- Eat your normal pre-race breakfast about two to three hours before the start.
- Test glucose 15 minutes before the start and treat as your team advised.
- Carry a planned number of gels and at least one additional fast-acting treatment.
- Test at planned checkpoints and after any surge or hill that feels hard.
- Test again within an hour after finishing.
For race-specific timing, When to Take Energy Gels During Half Marathon: A Step-by-Step Timing Guide offers a useful structure you can adjust with your own data.
Common Mistakes to Avoid
- Taking gels without testing first, which makes it impossible to tell whether you need them.
- Assuming a gel alone will prevent lows. Exercise can lower glucose faster than the gel can raise it.
- Stacking several gels at once, which can overshoot your target and cause nausea.
- Skipping the post-run test. Delayed lows can appear hours later, especially overnight.
- Trying a new gel on race day. Test every product in training first.
- Ignoring symptoms. Shakiness, sweating, confusion, or unusual irritability during a run means test and treat now.
Tips for Success
- Keep a consistent routine: same gel brand, same timing, same pre-run snack, when possible.
- Use a continuous glucose monitor if your clinician supports it, since trend arrows help you act early.
- Adjust for heat, altitude, and hills, which can all shift glucose unpredictably.
- Store gels where heat will not reach them. A melted or leaking packet is hard to use.
- Build your plan gradually. Change one variable at a time so you can see what works.
Recommended gear
Several supplies make energy gel use with diabetes safer and easier to manage on the run.
- Glucose tablets: fast, measured carbohydrate that is easy to chew when your glucose is low and your coordination is off. View on Amazon
- Continuous glucose monitor: shows trend arrows during the run so you can act before a low hits. Ask your clinician which system fits your plan. View on Amazon
- Running belt with pockets: keeps gels, a meter, and treatment within reach without bouncing. View on Amazon
- Medical ID bracelet: alerts responders to your diabetes if you are unable to communicate during an emergency. View on Amazon
FAQ
Can I use energy gels if I have type 1 diabetes?
Many people with type 1 diabetes use gels during long runs, but the amount and timing should be set with your diabetes team, especially if you use insulin. Your team may adjust insulin doses rather than relying only on carbohydrate.
How many grams of carbohydrate are in a typical gel?
Most standard energy gels contain roughly 20 to 25 grams of carbohydrate per packet, but labels vary. Always check the package for your specific product.
Should I take a gel before I start running?
That depends on your pre-run glucose reading and your clinician’s guidance. If your glucose is low before you start, treat it first and retest. A gel alone is not a substitute for a planned pre-run snack when one is needed.
What if I feel low but my glucose test looks normal?
Symptoms do not always match readings, and some meters or sensors have limits during exercise. If you feel shaky, sweaty, or confused, treat as if you are low, then test again when you can.
Are caffeinated gels safe with diabetes?
Caffeine can affect blood glucose and heart rate in some people. Check with your clinician before using caffeinated gels, and test your response in training first.
Do gels replace electrolytes?
No. Gels provide carbohydrate, and some contain small amounts of sodium, but long or hot runs may require separate electrolyte intake. Ask your team how to balance fluids and sodium with your medications.
How soon after a run should I test my glucose?
Test at about 30 minutes and again at 60 minutes after finishing. Delayed lows can occur, particularly after long efforts or when insulin doses were not adjusted.
Can I race a marathon with diabetes and use gels?
Many people with diabetes complete marathons. Success depends on thorough training, a tested race-day plan, and clear coordination with your diabetes team before race day.
Conclusion
Energy gels and diabetes can coexist in a safe, effective running routine when you test before, during, and after runs, and let your data guide your carbohydrate plan. Start with a clinician consultation, build a baseline in training, and carry a fast-acting treatment at all times. Practice your race-day plan until it feels routine, and adjust as your body and training change.
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About Ethan Brooks
Ethan Brooks is part of our editorial team and reviews and edits our marathon & half-marathon guides, checking product details against manufacturer specifications and owner feedback.
