Understanding if Does Vitamin C Change the Smell of Urine?

October 13, 2025 •

5 min read

As a water-soluble vitamin, any excess vitamin C that your body doesn't need is flushed out through your urine. This process is central to answering the common question: Does vitamin C change the smell of urine? The answer is that while the vitamin itself is not a major contributor to a distinct odor, the process of its excretion and other factors can influence the scent.

Quick Summary

Excess water-soluble vitamins are excreted in urine, but vitamin C does not typically cause a strong odor like B vitamins. Dehydration, certain foods, and underlying health issues are more likely culprits for significant changes in urine smell.

Key Points

Vitamin C and Urine Excretion: Excess vitamin C, a water-soluble vitamin, is naturally excreted through urine, potentially altering its color but not typically causing a strong odor.
Indirect Effect Via Hydration: A stronger urine smell when taking vitamin C is more often caused by dehydration, as concentrated urine has a higher level of waste products and a more potent ammonia-like scent.
B Vitamins are Bigger Culprits: Other water-soluble supplements, especially B-complex vitamins, are far more likely to cause strong or fishy-smelling urine than vitamin C.
Dietary Factors Play a Major Role: Many foods, including asparagus, garlic, and coffee, can cause temporary and noticeable changes in urine odor.
Check for Medical Causes: Persistent or foul-smelling urine can signal medical conditions like UTIs or diabetes and should be evaluated by a healthcare professional.
Maintain Proper Hydration: Drinking sufficient water is the most effective way to keep urine diluted and minimize any diet or supplement-related odor changes.

How the Body Processes Water-Soluble Vitamins

To understand the connection between nutrition and urine, it's helpful to know how the body handles different types of vitamins. Vitamins are broadly categorized as either fat-soluble or water-soluble. Fat-soluble vitamins, like A, D, E, and K, are stored in the body's fatty tissue and liver. They are not easily excreted and can build up to toxic levels if over-consumed. Water-soluble vitamins, including all the B vitamins and vitamin C, behave differently. They dissolve in water and are readily absorbed into the bloodstream. The body takes what it needs, and any excess is filtered by the kidneys and excreted in the urine.

When you consume a high dose of vitamin C, especially through supplements, your body absorbs a significant amount, but it cannot store the surplus. This excess ascorbic acid is promptly sent to the kidneys and then to the bladder for elimination. This increased excretion of waste products can cause a slight change in the concentration and composition of the urine, which in turn might alter its smell or color.

Direct vs. Indirect Effects of Vitamin C on Urine Odor

Contrary to popular belief, vitamin C itself is not known for causing a particularly strong or foul smell in urine. Other water-soluble vitamins, such as the B-complex vitamins, are much more notorious for this effect. Specifically, high doses of vitamin B6 can result in a pungent odor, and thiamine (B1) is sometimes associated with a fishy smell. While vitamin C supplements might cause urine to appear darker yellow or slightly orange, this color change is not necessarily linked to a strong odor and is a harmless sign of excretion.

The real link between vitamin C intake and a change in urine odor is more often an indirect one, related to hydration. Concentrated urine, which occurs when a person is dehydrated, will have a higher concentration of waste products and smell stronger of ammonia. Since many people take vitamin C supplements with little water, they may mistakenly attribute the strong smell to the vitamin, when in fact, it is a sign of needing to drink more fluids.

Other Dietary Influences on Urine Odor

Many foods and drinks can cause temporary changes in the smell of urine, often much more noticeably than vitamin C. The classic example is asparagus, which contains sulfur-containing compounds (asparagusic acid) that, when metabolized, produce distinct-smelling byproducts excreted in the urine. Similarly, other foods, including garlic, onions, coffee, and Brussels sprouts, contain compounds that can affect the odor of urine. These are often more potent and direct influences on urine smell than vitamin C intake.

Foods and Supplements Affecting Urine Odor

Asparagus: Contains asparagusic acid, which results in a potent, distinctive odor in urine for some individuals.
Garlic and Onions: These contain sulfur compounds that can lead to strong-smelling urine.
Coffee: The metabolites of certain compounds in coffee can produce a pungent aroma in urine.
B-complex Vitamins: High doses, especially of B1 and B6, are well-known to cause strong-smelling urine.
Certain Spices: Some spices can also leave their metabolic byproducts in urine, affecting its smell.

Medical Conditions Affecting Urine Odor

It is important to distinguish harmless dietary and supplemental changes from potential medical issues. A persistent, unusual, or foul odor could be a symptom of an underlying health problem. If you notice a lasting change in your urine's smell, especially accompanied by other symptoms, you should consult a healthcare provider.

Urinary Tract Infections (UTIs): Bacteria multiplying in the urinary tract can cause foul-smelling, cloudy urine, often with painful urination.
Diabetes: Uncontrolled diabetes, or high blood sugar, can lead to sweet or fruity-smelling urine due to excess sugar.
Liver Disease: Severe liver failure can cause a musty smell in urine due to the buildup of toxins.
Metabolic Disorders: Rare genetic disorders like phenylketonuria and maple syrup urine disease can result in distinctive urine odors from birth.

Vitamin C vs. Other Factors on Urine Odor and Color


Factor	Effect on Urine Odor	Effect on Urine Color
High-Dose Vitamin C	Minimal, if any, direct effect; any change is likely minor and related to concentration.	Can cause a harmless darkening to a deeper yellow or slight orange hue.
B-Complex Vitamins	Can cause a strong, pungent, or even fishy odor, particularly B1 and B6.	Often causes a distinct bright, almost fluorescent, greenish-yellow color.
Dehydration	Leads to a strong ammonia-like smell due to concentrated waste products.	Results in dark yellow or amber-colored urine.
Asparagus Consumption	Can produce a very pungent, sulfurous odor in the urine.	Typically no change in color.
Urinary Tract Infection (UTI)	Can cause a foul or strong, unpleasant smell due to bacteria.	Urine can become cloudy or dark.

Conclusion

In short, while vitamin C is a water-soluble vitamin that is excreted in the urine, it is not a primary cause of significant changes in urine odor. Any minor scent alteration is more likely due to dehydration, which can be linked to inadequate water intake with supplements. The most common and potent causes of altered urine smell are certain foods like asparagus and some other vitamin supplements, most notably the B-complex group. For persistent or concerning changes, it is always wise to consult a healthcare professional to rule out underlying medical conditions. Maintaining proper hydration is a simple and effective way to ensure healthy, mildly scented urine.

For more information on the role of vitamin C and other nutrients, a useful resource is the NIH's Office of Dietary Supplements.

How to Manage Changes in Urine Odor

Stay Hydrated: Drink plenty of water throughout the day to keep urine diluted and mild in odor.
Observe Your Diet: If you suspect certain foods are causing the issue, try eliminating them temporarily to see if the odor subsides.
Evaluate Supplements: If you take B-complex vitamins or high doses of vitamin C, and the odor is bothersome, discuss your dosage with a doctor or dietitian.
Improve Hygiene: Practice good personal hygiene to ensure any smells are not caused by external factors.
Regular Bathroom Breaks: Don't hold your urine for long periods, as this can concentrate waste products and intensify odors.

Frequently Asked Questions

High doses of vitamin C are excreted in urine, which can lead to a slightly altered concentration and may cause a very minor change in scent. However, it is far less likely to cause a strong odor than dehydration or other supplements like B-complex vitamins.

Yes, dehydration is a very common cause of strong-smelling urine. When you don't drink enough water, your urine becomes more concentrated with waste products like ammonia, making the odor much more noticeable.

The primary cause is usually high doses of B-complex vitamins. Vitamins like B6 (pyridoxine) and B1 (thiamine) are particularly known for causing a pungent or musty smell in urine as the body eliminates the excess.

Dietary causes, like from asparagus or coffee, are temporary and harmless. If the unusual odor persists for more than a few days, is accompanied by other symptoms like pain, fever, or cloudy urine, or is sweet-smelling, you should consult a doctor to rule out an infection or other medical condition.

The dark yellow or orange color is a harmless byproduct of the body processing and excreting excess vitamin C, especially in higher doses. This color change is not necessarily linked to a strong odor.

Yes, drinking plenty of water is one of the most effective ways to manage urine odor. It dilutes the concentration of any odor-causing compounds, whether from vitamins or other waste products.

In most cases, a strong smell from supplements is a harmless sign of your body excreting excess nutrients, particularly water-soluble ones. It is not generally a sign of a health problem unless accompanied by other symptoms like pain or fever.