Do vitamin C make your pee yellow? The surprising truth behind urine color

December 7, 2025 •

3 min read

Many people who take supplements notice their urine turning a neon or bright yellow color. While excess vitamin C can sometimes contribute to a darker, more orange-yellow hue, the primary culprit for that vibrant, fluorescent yellow is actually a different water-soluble vitamin. Here’s the real science behind why your supplements affect your urine’s color.

Quick Summary

The bright yellow or neon color often seen after taking supplements is caused by excess riboflavin (vitamin B2) being excreted through urine, not vitamin C. High doses of vitamin C may cause a harmless, darker orange-yellow tint.

Key Points

Riboflavin is the main cause: The vibrant, neon yellow urine often seen after taking supplements is primarily caused by excess riboflavin (vitamin B2), not vitamin C.
Vitamin C causes a different tint: High doses of vitamin C can cause urine to become a darker, orange-yellow shade, which is also a harmless side effect.
Excess water-soluble vitamins are excreted: Both vitamin C and B vitamins are water-soluble, meaning the body excretes any surplus it doesn't need via the urine.
Normal urine color is due to urochrome: A healthy pale to dark yellow urine color is a result of the pigment urochrome, with darker shades indicating dehydration.
Supplements contain high doses: Many multivitamins and B-complex supplements contain doses of riboflavin and other water-soluble vitamins that far exceed daily needs, leading to more pronounced color changes.
It is a normal and harmless process: A change in urine color due to excess water-soluble vitamins is not a sign of poor absorption or a health problem, but rather the body efficiently maintaining balance.

Why Your Pee Turns Yellow After Taking Vitamins

The color of your urine is influenced by hydration and bodily processes. The normal yellow comes from urochrome, a pigment from red blood cell breakdown. Hydration levels dictate the intensity, with well-hydrated individuals having lighter urine. When taking vitamin supplements, particularly water-soluble ones, changes in urine color are common. Water-soluble vitamins like B vitamins and vitamin C are not stored in large amounts and excess is excreted via urine. Fat-soluble vitamins (A, D, E, K) are stored in the body and do not typically affect urine color.

The Real Culprit: Riboflavin (Vitamin B2)

Riboflavin, or vitamin B2, is the primary cause of bright or fluorescent yellow urine after taking supplements. Many multivitamins contain riboflavin exceeding daily needs. Riboflavin has a natural yellow-green fluorescence, which colors the urine as the kidneys filter the excess. This is a harmless side effect indicating efficient excretion of the surplus.

Can Vitamin C Also Change Urine Color?

High doses of vitamin C supplements can cause urine to appear a darker, more orange-yellow, distinct from the neon color caused by riboflavin. As a water-soluble vitamin, excess vitamin C consumed, especially from supplements, is excreted through urine. This color change is not concerning and simply shows the body eliminating unneeded nutrients.

Water-Soluble vs. Fat-Soluble Vitamins

Vitamins are categorized by how they dissolve:

Water-Soluble Vitamins: B vitamins and vitamin C dissolve in water and are not stored. Excess is excreted in urine, potentially causing color changes. They need regular replenishment.
Fat-Soluble Vitamins: Vitamins A, D, E, and K are stored in fat and the liver. They are not excreted in urine to the same extent and don't affect its color. High intake can be toxic due to accumulation.

Other Factors That Influence Urine Color

Beyond vitamins, other factors can alter urine color:

Hydration Level: Dehydration results in dark yellow urine, while ample hydration leads to lighter urine.
Foods: Certain foods like beets (pink/red) or carrots (orange) can change urine color.
Medications: Some drugs, including certain laxatives and antibiotics, can cause orange or reddish-brown urine.
Health Conditions: Persistent or unusual color changes might signal underlying issues such as liver or kidney problems, or UTIs, often with other symptoms.

Comparison: Vitamin C vs. Vitamin B2 on Urine Color


Feature	Vitamin C	Riboflavin (B2)
Typical Color Effect	Darker orange-yellow	Bright or neon yellow
Reason for Color	Excess ascorbic acid excreted via urine	Riboflavin's natural yellow fluorescence
Harmless?	Yes, a normal side effect of excess intake	Yes, excess is safely excreted
Water-Soluble?	Yes, excess is not stored	Yes, excess is not stored
Source Type	Supplements (especially high-dose), citrus fruits, peppers	Multivitamins, B-complex supplements, milk, eggs, meat

Conclusion: The Final Word on Vitamin C and Yellow Pee

The appearance of bright yellow urine after taking supplements is usually a harmless result of the body eliminating excess riboflavin, not vitamin C. While high doses of vitamin C can cause a darker, orange-yellow tint, it lacks the fluorescent quality of B2. This excretion is a normal function for water-soluble vitamins. If you have concerns about persistent or unusual urine color changes or other symptoms, consult a healthcare professional. For more information on vitamin processing, refer to the MedlinePlus Medical Encyclopedia.

Frequently Asked Questions

The most significant difference is the color intensity. Excess riboflavin (vitamin B2) causes a vivid, fluorescent or neon yellow color, while high doses of vitamin C typically result in a darker, more orange-yellow tint.

No, it is not bad and is generally harmless. This simply means your body has absorbed the vitamins it needs and is excreting the excess, a normal process for water-soluble vitamins like riboflavin and vitamin C.

Not at all. A bright yellow color indicates that your body has absorbed what it needs from the supplement and is eliminating the surplus. This is the normal metabolic process for water-soluble vitamins.

The color change is temporary. The bright yellow color typically fades within a few hours to a day as the excess vitamins are fully cleared from your system by the kidneys.

You can try taking a lower dose of a supplement or choosing a time-released formula, which releases the vitamins more slowly into your system. However, the color change is harmless and medically unnecessary to prevent.

Hydration level is the most common factor, but other causes include certain foods (like beets or carrots), medications (like some antibiotics), food dyes, and in rare cases, underlying health conditions.

If your urine is consistently a normal, pale yellow, it is a sign of good hydration. If it is persistently and unusually bright or dark without a clear cause (like supplements), or accompanied by other symptoms, it's best to consult a doctor.