Understanding Which of the following symptoms may be seen in pantothenic acid toxicity?

October 31, 2025 •

2 min read

Because pantothenic acid (vitamin B5) is a water-soluble vitamin, any excess is readily excreted by the body, making toxicity from dietary sources extremely rare. The question, 'Which of the following symptoms may be seen in pantothenic acid toxicity?' is best answered by looking at the effects of very high-dose supplementation, where minimal, largely gastrointestinal issues are the most common finding.

Quick Summary

Pantothenic acid toxicity in humans is very rare, with no Tolerable Upper Intake Level set due to a lack of severe adverse effects. The main symptom reported from extremely high supplemental doses (around 10 grams daily) is mild diarrhea and gastrointestinal distress.

Key Points

Gastrointestinal Distress: The most common symptom associated with extremely high doses (10 grams or more) of pantothenic acid supplementation is mild diarrhea and abdominal pain.
Low Toxicity: Pantothenic acid is a water-soluble vitamin, and the body efficiently excretes excess amounts, making toxicity from dietary sources highly unlikely.
No Upper Limit Set: Due to the lack of reports detailing severe adverse effects, health authorities have not established a Tolerable Upper Intake Level (UL) for pantothenic acid.
Dose Dependent: The mild side effects, when they occur, are directly related to the very high supplemental dosage and are not a risk for individuals consuming recommended amounts.
Contrast with Deficiency: The symptoms of very high intake are minimal and temporary, contrasting sharply with the more serious, though rare, symptoms of pantothenic acid deficiency, such as burning feet syndrome.
Consult a Professional: Anyone considering high-dose supplementation should consult a healthcare provider, especially if taking other medications, to ensure safety.
Food is Key: The safest way to obtain adequate pantothenic acid is through a varied and balanced diet, which provides sufficient amounts without risk.

The Minimal Risks of Excessive Pantothenic Acid

Pantothenic acid, also known as vitamin B5, is an essential water-soluble vitamin. Due to its water-soluble nature, excess amounts are typically excreted, making toxicity from food sources extremely unlikely. Adverse effects have only been observed with very high supplemental doses.

Primary Symptoms of High-Dose Supplementation

The most common symptoms associated with very high supplemental intakes of pantothenic acid are mild gastrointestinal issues.

Diarrhea: Doses of 10 grams or more per day can cause mild diarrhea.
Abdominal Pain: Stomach upset has been reported with large intakes.
Nausea: Some individuals experience nausea at very high dosages.

These symptoms occur at intakes several thousand times the Recommended Dietary Allowance of 5 mg per day for adults, highlighting the vitamin's low toxicity.

Absence of a Tolerable Upper Intake Level (UL)

No Tolerable Upper Intake Level (UL) has been established for pantothenic acid due to the lack of evidence of serious adverse effects in humans. This lack of a UL underscores the minimal risk associated with higher intakes.

Differentiating Forms and Related Substances

While generally well-tolerated, derivatives like pantethine and dexpanthenol may have slightly different side effects, such as mild gastrointestinal issues or skin irritation with topical use, respectively.

Comparison: High Intake vs. Deficiency Symptoms

A comparison of the effects of high intake versus deficiency highlights the minimal risk of toxicity:


Feature	High Supplemental Intake (Toxicity)	Deficiency
Prevalence	Extremely rare in humans, requiring very large doses	Extremely rare in developed countries, typically seen with severe malnutrition
Primary Symptom	Mild gastrointestinal issues, especially diarrhea	Numbness and burning of hands and feet (burning feet syndrome)
Other Symptoms	Abdominal pain, nausea	Fatigue, headache, irritability, restlessness, sleep disturbances, stomach pain
Onset	Acute, linked directly to high-dose supplementation	Gradual, developing over time with insufficient intake

Case Reports and Interactions

A single case report of a serious reaction occurred in an elderly woman taking high-dose biotin and pantothenic acid. While a direct link was not confirmed, it emphasizes the need for medical supervision with high-dose supplements. Drug interactions are not well-documented.

How to Avoid Risks

Consuming pantothenic acid from a balanced diet of foods like meat, whole grains, legumes, eggs, milk, mushrooms, and avocados is sufficient and safe for most adults. High-dose supplementation should only be done under medical guidance.

Conclusion

Severe pantothenic acid toxicity is highly improbable due to its water-soluble nature. The most common symptoms at very high supplemental doses are mild, temporary gastrointestinal issues like diarrhea. No UL has been set, confirming its safety profile. Meeting needs through a balanced diet is recommended, and high-dose supplements require medical advice.

For more detailed information, refer to the NIH Office of Dietary Supplements factsheet.

Frequently Asked Questions

The primary symptom reported from consuming extremely high supplemental doses of pantothenic acid is mild diarrhea and general gastrointestinal distress.

No, toxicity from dietary sources is virtually impossible because pantothenic acid is water-soluble and the body effectively excretes any excess amounts.

Side effects like mild diarrhea are typically only seen at very large supplemental doses, such as 10 grams (10,000 mg) or more per day.

No, a Tolerable Upper Intake Level (UL) has not been set for pantothenic acid because there are no reports of severe adverse health effects from high intakes.

Toxicity symptoms are typically limited to mild, temporary gastrointestinal upset at very high doses, while deficiency, though rare, can cause more severe issues like nerve damage (burning feet syndrome), fatigue, and irritability.

While not well-documented, a case report involving a combination of high-dose biotin and pantothenic acid showed a serious adverse event. Consulting a doctor is essential when considering high-dose supplementation.

Good sources include beef, chicken, organ meats, eggs, milk, whole grains, and certain vegetables like mushrooms and avocados.

The recommended intake for pregnant women is 6 mg daily and is considered safe. Taking doses higher than the recommended amount should be discussed with a healthcare provider, but severe toxicity is not expected.