How much sugar increases after tea and how to manage it

December 10, 2025 •

4 min read

Studies have shown that added sugar, especially in beverages like tea, can cause a significant and rapid increase in blood sugar levels. Understanding precisely how much sugar increases after tea is vital for anyone monitoring their glucose, but the answer depends heavily on what you add to your cup.

Quick Summary

The impact of tea on blood sugar is determined by added sweeteners like sugar or honey. Unsweetened teas generally do not cause significant spikes, but sugary versions or milks can elevate glucose levels.

Key Points

Source of Sugar: The blood sugar increase after tea is caused by added sugar, not the tea leaves themselves.
Unsweetened is Best: Plain green, black, or herbal tea has a negligible effect on blood sugar and may offer health benefits.
Caffeine's Dual Role: While caffeine can temporarily increase blood sugar in some individuals by affecting insulin sensitivity, the effect is typically mild with moderate tea consumption.
The Problem with Sweetened Drinks: Sugary iced tea, bubble tea, and other sweetened preparations cause significant blood glucose spikes due to high simple carbohydrate loads.
Lactose Adds Up: Milk contains lactose, a natural sugar, which can contribute to a blood sugar rise, especially in larger quantities.
Better Alternatives: Use natural flavorings like lemon, mint, or cinnamon instead of sugar to maintain flavor without impacting glucose.
Individual Variation: Monitor your own blood glucose levels, as personal tolerance to caffeine and different teas can vary.

Unpacking the True Impact of Tea on Blood Sugar

When we ask, “How much sugar increases after tea?” it’s important to clarify what's actually in your cup. The tea leaves themselves, in their natural state, do not contain sugar and do not significantly raise blood glucose. The entire effect on your blood sugar comes from any additions you make, such as sugar, honey, milk, or sweetened syrups. For individuals managing diabetes or blood sugar, this distinction is critical for making healthier choices.

The Glycemic Response: Sweetened vs. Unsweetened Tea

The most significant factor in a tea-induced blood sugar spike is the glycemic load of the added sweetener. Glycemic index (GI) is a measure of how quickly a food raises blood sugar levels. While plain brewed tea has a GI of virtually zero, adding a simple carb like sugar or honey changes the equation drastically.

Added Sugar and Honey: These simple carbohydrates are rapidly absorbed into the bloodstream, causing a swift and substantial spike in blood glucose. The higher the quantity added, the more pronounced the spike will be. This is particularly problematic for individuals with insulin resistance or diabetes, as their bodies struggle to produce or utilize enough insulin to manage the influx of sugar effectively.
Milk: While not as potent as pure sugar, milk contains lactose, a natural sugar that can also cause a minor increase in blood sugar. The amount of lactose in a small splash of milk is generally minimal, but in larger quantities or in milky, sweetened concoctions, the effect is compounded.
Unsweetened Tea: Green, black, or herbal tea without any additions is a calorie-free, sugar-free beverage. Research suggests that certain unsweetened teas, like green and black tea, contain polyphenols and other compounds that may actually help regulate blood sugar and improve insulin sensitivity over the long term.

The Role of Caffeine

Caffeine, a natural component in true teas (black, green, oolong, etc.), adds another layer of complexity. Some studies suggest that caffeine can affect blood sugar levels, especially for individuals with type 2 diabetes.

Potential for Insulin Resistance: Caffeine can trigger a hormonal response in some individuals that can cause a temporary rise in blood sugar. This is because it can make your body's cells less sensitive to insulin, a condition known as insulin resistance. The effect is often individual-specific.
Increased Alertness: Caffeine increases the release of adrenaline, which signals the liver to release stored glucose for an energy boost. For those with compromised glucose control, this can lead to an undesirable rise in blood sugar.
Moderation is Key: The amount of caffeine in a cup of tea is generally much lower than in coffee. For many people, a moderate intake of tea will not cause significant blood sugar issues related to caffeine, especially when consumed unsweetened.

Comparison Table: Estimated Blood Sugar Impact

This table illustrates the potential blood sugar effects of different tea preparations. The values are general estimations and can vary based on individual metabolism, quantity, and specific ingredients.


Tea Type	Typical Sugar/Content	Estimated Blood Sugar Impact	Health Notes
Black Tea (Unsweetened)	0g sugar	Negligible	Polyphenols may improve insulin sensitivity.
Green Tea (Unsweetened)	0g sugar	Negligible	Polyphenols may help with glucose uptake.
Herbal Tea (Unsweetened)	0g sugar	Negligible	Specific herbs may offer benefits (e.g., chamomile, cinnamon).
Tea with 1 tsp Sugar	~4g sugar	Moderate, rapid spike	Quick energy boost, followed by potential crash.
Tea with 2 tsp Honey	~14g sugar	Strong, rapid spike	Similar to sugar, but with a different nutritional profile.
Bubble Tea	20+ tsp sugar	Very strong, rapid spike	Extremely high sugar content, causing a significant surge.
Iced Sweet Tea	~20g-30g sugar	Strong spike	Varies by preparation; often very high in sugar.

How to Enjoy Tea While Managing Blood Sugar

For those who love tea but need to be mindful of blood sugar, here are some actionable tips:

Embrace Unsweetened Tea: The simplest and most effective strategy is to enjoy tea without any added sugar. Savor the natural, complex flavors of different varieties.
Explore Natural Flavor Enhancers: Add a squeeze of lemon or lime, a sprig of mint, or a dash of cinnamon for flavor without adding sugar. Cinnamon, in particular, has been studied for its potential blood-sugar-lowering properties.
Limit Milk Intake: If you prefer milky tea, use a small splash of low-fat milk or an unsweetened plant-based alternative to minimize the impact of lactose.
Switch to Herbal Teas: Many herbal infusions are naturally sweet and don't contain caffeine, which can be a beneficial alternative. Chamomile and peppermint are popular options.
Opt for Stevia: If you can't give up sweetness entirely, consider using non-nutritive sweeteners like stevia, which do not contain carbohydrates and will not affect blood sugar.
Monitor Your Response: Since caffeine sensitivity and metabolic responses vary, track your blood glucose levels after consuming tea to understand how your body reacts to different types and preparations.

Conclusion

The question of how much sugar increases after tea is fundamentally a question about personal choice and preparation. Unsweetened tea is not only a zero-sugar beverage but also offers potential health benefits related to glucose metabolism and insulin sensitivity. The moment you introduce sweeteners, milk, or sugary add-ins, you are adding carbohydrates that will elevate your blood sugar. By choosing unsweetened options and exploring natural flavor alternatives, you can continue to enjoy a flavorful and healthy cup of tea without compromising your blood sugar goals.

For more information on the impact of various drinks on blood glucose, consult trusted medical resources like the American Diabetes Association.

Frequently Asked Questions

No, plain brewed black or green tea contains no sugar or calories and does not raise blood sugar levels. In fact, compounds within these teas, like polyphenols, have been linked to improved glucose metabolism.

Adding just one teaspoon of sugar (about 4 grams of carbohydrates) will cause a noticeable but temporary increase in blood sugar. The severity depends on your overall health, but for most people, it's a manageable spike.

Yes, milk contains lactose, a natural sugar. A small splash will have a minimal effect, but adding larger amounts of milk or using sweetened dairy products will increase your blood glucose level.

For a healthy individual, blood sugar levels typically peak between 45 and 90 minutes after consuming a sugary drink and return to normal within 2-3 hours. For someone with diabetes, the return to baseline can take much longer.

Bubble tea is very bad for blood sugar. It often contains a large amount of added sugar from syrups and sweetened bases, which can cause a very significant and rapid blood glucose spike.

Unsweetened herbal teas like chamomile or cinnamon tea, and traditional green tea, are often recommended for blood sugar management due to their beneficial compounds. Dark tea, a fermented variety, has also shown promise in studies.

Yes, many people with diabetes use non-nutritive sweeteners like stevia to sweeten tea without adding calories or affecting blood glucose. However, research on artificial sweeteners is ongoing and they should be used in moderation.