Can I Take Too Much Vitamin B5? Understanding Risks and Safety

November 15, 2025 •

3 min read

Pantothenic acid, or vitamin B5, is generally considered safe, with no official Tolerable Upper Intake Level established by health authorities. However, some people may still wonder, "Can I take too much vitamin B5?" The answer lies in understanding the difference between dietary intake and very high supplemental doses.

Quick Summary

Pantothenic acid is highly safe, but extremely high supplemental doses over 10 grams daily may cause mild gastrointestinal issues like diarrhea. Toxicity is very rare.

Key Points

Toxicity is Rare: True toxicity from pantothenic acid is not reported in humans due to its water-soluble nature and efficient excretion.
No Upper Limit: Health authorities have not established a Tolerable Upper Intake Level (UL) for Vitamin B5 because of its low risk profile.
Megadoses Cause Issues: Extremely high supplemental doses of 10 grams (10,000 mg) or more daily can cause mild diarrhea and gastrointestinal upset.
Food is Safe: It is virtually impossible to consume too much vitamin B5 from normal food sources alone.
Side Effects are Mild: The most common adverse effects from high supplemental intake are gastrointestinal and resolve upon discontinuation.
RDA is Low: The recommended daily intake for adults is 5 mg, an amount easily obtained from a balanced diet.

Understanding Vitamin B5 (Pantothenic Acid)

Vitamin B5, also known as pantothenic acid, is an essential water-soluble vitamin that plays a critical role in human health. It is a component of coenzyme A (CoA), which is vital for numerous enzymatic reactions in the body. These functions include converting food into energy, synthesizing and breaking down fats, and helping to synthesize cholesterol and steroid hormones. Because it is crucial for basic metabolic functions, B5 is found in virtually all living cells.

What are the main sources of Vitamin B5?

Since pantothenic acid is widespread in both plant and animal foods, a deficiency is extremely rare in developed countries. Excellent food sources include:

Beef, poultry, and organ meats
Whole grains, including oats and brown rice
Mushrooms, avocados, potatoes, and broccoli
Peanuts and sunflower seeds
Eggs and milk
Fortified cereals and energy drinks

Is There an Established Upper Intake Level?

The Food and Nutrition Board at the National Academies of Sciences, Engineering, and Medicine has not set a Tolerable Upper Intake Level (UL) for vitamin B5. A UL is the maximum daily intake unlikely to cause adverse health effects in the general population. The absence of a UL is because there have been no reports of vitamin B5 toxicity in humans with high intakes, and no clinically significant adverse effects have been observed in short-term studies using higher doses.

Can You Overdose on Vitamin B5 from Food?

Overdosing on vitamin B5 from dietary sources is virtually impossible. Your body only absorbs a fraction of pantothenic acid when intake is high, and any excess is simply excreted in the urine because it is a water-soluble vitamin. Therefore, focusing on a varied and balanced diet that naturally contains B5 is the safest way to meet your daily needs.

Potential Side Effects of High Supplemental Doses

While food sources are safe, taking very high doses of pantothenic acid supplements, typically 10 grams (10,000 mg) or more per day, can cause mild gastrointestinal upset. The most commonly reported side effect is diarrhea. In clinical trials involving high doses, subjects reported mild and non-persistent gastrointestinal issues, such as bloating and cramping. It's important to differentiate these mild, reversible side effects from true toxicity, which is not known to occur in humans.

Other Reported Adverse Effects

According to some clinical reports, the administration of high supplemental doses (often in specific, high-dose therapeutic contexts) has been associated with other side effects, although these are less common and may be related to other factors. These include:

Headache
Weakness or dizziness
Nausea
Abdominal pain
Hypersensitivity reactions (rash, itching, swelling)

It is crucial to note that these effects are associated with the administration of supplemental doses far exceeding the normal dietary intake, and typically resolve when intake is reduced or stopped.

Comparing Normal Intake vs. Excessive Supplementation


Feature	Normal Dietary Intake	Excessive Supplemental Intake
Source	Whole foods, fortified foods	High-dose supplements, B-complex
Daily Amount	Around 5 mg (Adult Adequate Intake)	Often 1,000 mg to 10,000 mg+
Absorption	Efficiently absorbed	Absorption rate decreases at high intake
Excretion	Excess excreted normally in urine	Large amounts excreted in urine
Side Effects	None reported	Mild diarrhea, upset stomach
Health Risk	Extremely low to none	Very low, mainly GI distress at high doses

Conclusion: Safe and Sound

In conclusion, the risk of taking too much vitamin B5 is extremely low, especially from food sources. Since it is a water-soluble vitamin, your body efficiently flushes out any excess, preventing true toxicity. The most significant adverse effect reported with very high supplemental doses is mild gastrointestinal discomfort, which is temporary and not life-threatening. If you are concerned about your supplement dosage, it is always best to consult a healthcare provider. For more information, you can visit the NIH Office of Dietary Supplements fact sheet on Pantothenic Acid. For most healthy individuals, meeting the recommended daily intake through a balanced diet is sufficient and poses no risk of overconsumption.

Frequently Asked Questions

No, it is virtually impossible to consume an unsafe level of vitamin B5 from food sources alone, as it is a water-soluble vitamin that is easily excreted by the body.

Very high supplemental doses, typically 10 grams (10,000 mg) per day or higher, are considered megadoses and have been associated with mild side effects.

Larger amounts of pantothenic acid, up to 1 gram (1000 mg), seem to be safe for most people but do increase the chance of mild side effects such as diarrhea.

True toxicity from vitamin B5 is extremely rare. Any reported side effects are typically limited to mild digestive issues at extremely high doses and are not life-threatening.

No, a Tolerable Upper Intake Level (UL) has not been set for pantothenic acid by major health organizations due to the lack of reported toxicity in humans.

The most widely reported symptom of high supplemental vitamin B5 intake is mild diarrhea or upset stomach at very high doses. Other less common effects at high doses can include nausea and abdominal pain.

B-complex supplements typically contain safe, low amounts of vitamin B5 and other B vitamins that are unlikely to cause toxicity. The risk of toxicity is mainly associated with taking very high doses of isolated pantothenic acid supplements.

The recommended adequate intake for adults is 5 mg per day, which is easily obtainable through a balanced diet.