What are the side effects of white mulberry leaves?

January 11, 2026 •

4 min read

While often praised for its potential to help manage blood sugar, white mulberry leaf is not without its risks, with a recent high-profile death linked to its ingestion raising questions about its safety. Like any herbal supplement, it can cause various side effects, ranging from mild digestive discomfort to potentially serious interactions with prescription medications.

Quick Summary

White mulberry leaves can cause common side effects such as bloating, constipation, gas, and loose stools, while serious adverse reactions are rare but possible. It significantly interacts with medications for diabetes and cholesterol, potentially leading to hypoglycemia and additive effects. Certain groups, including pregnant women and children, are advised to avoid it due to a lack of safety research.

Key Points

Digestive Discomfort: Common side effects include bloating, gas, constipation, and diarrhea due to the leaf's effect on carbohydrate digestion.
Hypoglycemia Risk: When taken with diabetes medication, white mulberry leaf can cause blood sugar to drop dangerously low.
Drug Interactions: It can interact with diabetes medications and potentially with cholesterol-lowering drugs and immunosuppressants.
Contraindicated for Some: Pregnant and breastfeeding women, children, and older adults should avoid it due to limited safety data.
Insufficient Regulation: As a dietary supplement, its quality and safety are not rigorously regulated by the FDA, posing a risk of unwanted contaminants.
Limited Long-Term Research: Most studies on its safety have been short-term, with data beyond 12 weeks of use being scarce.

Common Side Effects of White Mulberry Leaf

For many individuals, the most frequently reported side effects of white mulberry leaf and its extracts are related to the digestive system. This is often due to its mechanism of action, specifically the compound 1-deoxynojirimycin (DNJ), which inhibits the breakdown of carbohydrates in the gut. This can lead to increased fermentation in the intestines.

Digestive Discomfort

Bloating and gas: In some people, the undigested carbohydrates can ferment in the large intestine, causing uncomfortable bloating and excessive gas.
Constipation: While less common, some users report constipation after taking mulberry leaf supplements.
Diarrhea or loose stools: The most frequently cited digestive issue is loose stools or diarrhea, particularly with higher doses.

Potential for Hypoglycemia and Medication Interactions

White mulberry leaf's ability to lower blood sugar is a key benefit but also a significant safety concern, especially for those on medication.

Danger of Hypoglycemia

For individuals with diabetes, taking white mulberry leaf in addition to prescribed diabetes medications, such as insulin, can cause a dangerous drop in blood sugar levels, a condition known as hypoglycemia. Symptoms of hypoglycemia include dizziness, excessive sweating, and fatigue.

Interactions with Other Medications

Diabetes Medications: The blood sugar-lowering effect of white mulberry leaf can be amplified when taken alongside conventional diabetes drugs like glipizide or metformin, necessitating close blood sugar monitoring and potential dosage adjustments by a healthcare provider.
Cholesterol-Lowering Medications: White mulberry has been shown to lower cholesterol. When combined with prescription cholesterol medications, there is a risk of additive effects, which could increase the severity of side effects associated with the medication.
Immunosuppressants: Research suggests that mulberry may interact with medications like cyclosporine by affecting the cellular pumps that move drugs in and out of cells. This could change the medication's effectiveness and side effects.

Contraindications and At-Risk Groups

Certain populations are advised to avoid white mulberry leaf due to insufficient research or known risks.

Pregnancy and Breastfeeding

There is a lack of reliable information concerning the safety of white mulberry leaf during pregnancy and breastfeeding. For this reason, medical experts generally recommend avoiding its use to remain on the safe side.

Children

The safety and efficacy of white mulberry leaf in children have not been adequately studied, so its use is not recommended for this demographic.

Older Adults

Senior citizens, who may be more sensitive to supplement side effects and more likely to be on other medications, should exercise caution. A consultation with a healthcare provider is essential.

Allergies

People with known allergies to white mulberry or birch pollen may experience allergic reactions, such as skin irritation, coughing, or difficulty breathing. Severe allergic reactions require immediate medical attention.

Comparison Table: White Mulberry Leaf vs. Cinnamon for Blood Sugar


Feature	White Mulberry Leaf	Cinnamon (Cassia)
Primary Mechanism	Contains 1-deoxynojirimycin (DNJ) which blocks carbohydrate absorption in the gut.	Improves insulin sensitivity and affects carbohydrate metabolism [search result not shown, general knowledge].
Common Side Effects	Gastrointestinal issues (bloating, gas, constipation, diarrhea).	Can cause digestive upset, and high doses of cassia cinnamon contain coumarin, which can be toxic to the liver [search result not shown, general knowledge].
Medication Interactions	Strong interaction risk with diabetes and cholesterol drugs.	Potential to interact with blood thinners and diabetes medications [search result not shown, general knowledge].
Regulation	Dietary supplements are not highly regulated by the FDA, leading to potential contamination risks.	Minimally regulated as a supplement, with quality varying by brand [search result not shown, general knowledge].
Long-Term Safety	Safety data is limited beyond 12 weeks of use.	Long-term use of high-coumarin varieties can pose a liver risk [search result not shown, general knowledge].

Factors Influencing Side Effects

Several factors can influence the likelihood and severity of side effects from white mulberry leaf:

Dosage: Higher doses of white mulberry leaf extract increase the risk of experiencing adverse effects like digestive upset.
Formulation: The form in which it is consumed can matter. Extracts standardized for specific compounds may have more potent effects and risks than dried, unprocessed leaves in tea.
Individual Sensitivity: A person's unique physiology and gut health can dictate how they react to the supplement.
Use Duration: Most clinical studies on white mulberry have been relatively short, lasting up to 12 weeks, meaning the long-term safety is not well established.

Important Considerations for Safe Use

It is crucial to approach the use of white mulberry leaf with caution and a healthy dose of skepticism, given the limited long-term human studies and minimal regulatory oversight of herbal supplements. Always inform your healthcare providers and pharmacists about all supplements, including herbal ones, to avoid potential interactions and side effects. If any concerning symptoms appear, stop taking the supplement immediately and consult a medical professional. A thorough medical evaluation is vital before starting any new herbal remedy, especially for individuals with pre-existing conditions like diabetes.

Conclusion

While white mulberry leaf offers potential benefits for blood sugar and cholesterol management, users must be aware of its side effects, which range from common gastrointestinal distress to serious medication interactions. The lack of comprehensive long-term safety data, combined with potential risks for certain individuals like those on diabetes medication or who are pregnant, underscores the importance of medical consultation before use. By understanding the full risk profile and speaking with a doctor, consumers can make informed decisions about whether white mulberry leaf is the right option for their health goals.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Consult a healthcare professional before starting any new supplement regimen.

National Center for Complementary and Integrative Health (NCCIH)

Frequently Asked Questions

The most common side effects of white mulberry leaf are related to the gastrointestinal system and include bloating, gas, constipation, and loose stools.

Yes, white mulberry leaf can lower blood sugar. For individuals with diabetes, especially those on blood sugar-lowering medications like insulin, taking white mulberry leaf could cause hypoglycemia, a dangerous drop in blood sugar.

Pregnant and breastfeeding women, children, older adults, and people taking diabetes or cholesterol medication should avoid or use white mulberry leaves with extreme caution and under a doctor's supervision.

Yes, it is known to interact with diabetes medications by potentially causing dangerously low blood sugar. It can also have additive effects with cholesterol-lowering medications and interfere with immunosuppressants.

Limited reliable information exists on the long-term safety of white mulberry leaf. Most studies have been short-term (up to 12 weeks), so the effects of prolonged use are not well understood.

If you experience severe side effects such as difficulty breathing, severe allergic reaction symptoms, or very low blood sugar, seek immediate medical attention.

To minimize risk, always consult a healthcare professional before starting. Stick to recommended dosages and avoid use if you are in a high-risk group. Be vigilant for any adverse symptoms and stop use if they occur.

Some studies suggest white mulberry may aid weight loss by affecting carbohydrate digestion and metabolism. However, research is still limited, and the supplement should not be seen as a primary weight loss solution. Always discuss options with a healthcare provider.