Nutrition Diet: Do you lose vitamin C in sweat?

October 12, 2025 •

4 min read

An individual can lose up to 2.5 liters of sweat per hour during intense exercise in the heat. While this is a significant fluid and electrolyte loss, it raises a common question for active individuals: do you lose vitamin C in sweat, and if so, how much?

Quick Summary

Water-soluble vitamins, including vitamin C, are lost in small amounts through sweat during exercise, but the body primarily excretes excess through urine. For most people with a balanced diet, this loss is not significant enough to cause a deficiency, although athletes in hot conditions may need to pay closer attention to their intake to maintain levels and support recovery.

Key Points

Minimal Loss in Sweat: Only a small, negligible amount of vitamin C is lost through sweat for the average person.
Urine is the Main Excretion Route: As a water-soluble vitamin, any excess vitamin C is primarily excreted through the kidneys via urine.
High Sweat Volume Increases Losses: For high-performance athletes with very high sweat rates, the cumulative loss of vitamin C can be more significant.
Vitamin C Supports Recovery: This antioxidant is crucial for fighting oxidative stress and supporting collagen synthesis, which aids in muscle repair after intense exercise.
Dietary Replenishment is Key: A balanced diet rich in fruits and vegetables is the most effective and natural way to replenish any lost vitamins.
Consider Supplements for Intense Training: Some athletes may benefit from moderate vitamin C supplementation, particularly during periods of intense training, but a professional should guide this.

The Science of Sweat and Water-Soluble Vitamin Loss

Sweating is a natural and essential physiological process, primarily for thermoregulation, but it also serves as a route for the body to excrete various substances. The composition of sweat is mostly water, with a small percentage of dissolved solutes. While the most abundant minerals lost are electrolytes like sodium, chloride, and potassium, small quantities of water-soluble vitamins, including vitamin C and B vitamins, are also present.

Unlike fat-soluble vitamins (A, D, E, and K), which are stored in the body's fatty tissues and liver, water-soluble vitamins are not stored in significant reserves. Instead, any excess is typically flushed from the body, with the kidneys being the primary route of excretion. The kidneys' filtration process and the reabsorption mechanisms in the sweat glands minimize the amount of vitamin C lost through perspiration. Early studies on this topic had inconsistent results, possibly due to analytical limitations, but it is now widely agreed that the amount of vitamin C lost through sweating is generally negligible for most individuals with an adequate dietary intake.

However, for high-performance athletes engaged in intense or prolonged exercise, especially in hot and humid conditions, the equation changes. With sweat rates that can reach several liters per hour, the cumulative loss of even small concentrations of water-soluble vitamins can become more significant over time. For these individuals, maintaining a consistent intake is more important to support bodily functions and recovery.

The Impact of Exercise on Vitamin C

Vitamin C, also known as ascorbic acid, is a powerful antioxidant that plays a crucial role in several functions relevant to exercise. Exercise, particularly intense training, increases the production of free radicals and causes oxidative stress in the body. As an antioxidant, vitamin C helps neutralize these free radicals, protecting cells from damage and aiding in recovery. It is also essential for collagen synthesis, a protein vital for repairing connective tissues such as tendons, ligaments, and skin, which can experience micro-tears during high-impact activities.

Antioxidant Function: Vitamin C neutralizes free radicals generated by intense physical activity, helping to reduce oxidative stress and muscle damage.
Immune Support: Intense exercise can cause a temporary dip in immune function. Vitamin C can help maintain normal immune function, especially during and after extreme physical activity, helping to prevent infections.
Collagen Synthesis: It is required for the production of collagen, a structural protein important for the repair and recovery of connective tissues.
Iron Absorption: It enhances the absorption of non-heme iron (from plant-based foods), which is important for oxygen transport to muscles and maintaining energy levels.

A Comparison of Vitamin Loss and Replenishment

How much you need to focus on replenishing vitamins and minerals depends on the intensity and duration of your activity. Here is a comparison of typical sweat losses and replenishment strategies.


Feature	Moderate, short-duration exercise	Intense, long-duration exercise in the heat
Sweat Rate	Low (less than 1 L/hr)	High (up to 2.5 L/hr or more)
Electrolyte Loss	Minimal; easily replaced with normal meals	Significant; intentional replenishment via sports drinks or salty foods is advised
Vitamin C Loss	Negligible and easily offset by a balanced diet	Accumulates with high sweat volume, potentially impacting those with low intake
Replenishment Strategy	Water and regular meals with fruits/vegetables are sufficient	Consider water with electrolytes, sports drinks, or nutrient-dense foods, especially in the recovery period
Need for Supplements	Rarely necessary; can get enough from diet alone	May be beneficial for some athletes to ensure optimal levels, but not a replacement for a whole-food diet

Replenishing Lost Nutrients Through Diet

For most people, replenishing any minor vitamin and mineral losses from sweating can be achieved effectively by focusing on a nutrient-rich diet. The best and most natural way to ensure adequate intake of vitamin C and other water-soluble vitamins is through whole foods. No sports drink or supplement can replicate the full nutritional package provided by nature.

Excellent Food Sources of Vitamin C: Citrus fruits (oranges, kiwi), berries (strawberries), cruciferous vegetables (broccoli, spinach, bell peppers), and other produce.
Combining for Recovery: After a hard workout, a recovery meal containing carbohydrates and protein, paired with fruits and vegetables, is ideal. For example, a smoothie with fruit and yogurt is a great option that delivers carbohydrates, protein, and potassium.

For athletes or individuals with specific dietary needs, such as vegetarians relying on plant-based iron, vitamin C intake is doubly important. Vitamin C significantly enhances the absorption of non-heme iron, making it a critical nutrient for preventing iron deficiency and fatigue.

Should You Supplement?

While a balanced diet is the cornerstone of good nutrition, there are specific scenarios where supplementation may be considered, particularly for those with a high training volume or inadequate dietary intake. For vitamin C, some studies suggest that supplementing with moderate doses (e.g., 200-500 mg/day) before and after intense sessions can help support muscle recovery and immune function. However, high doses of antioxidants like vitamin C can potentially interfere with the adaptive signaling pathways of exercise, so moderation is key. Consulting with a healthcare professional or sports dietitian is always the best approach before starting any new supplement regimen.

Conclusion

While the answer to 'do you lose vitamin C in sweat?' is technically 'yes,' the amount is typically insignificant for most people engaging in standard physical activity. The body's efficient systems for handling water-soluble vitamins mean that the primary route of excretion is through urine. For the average person, focusing on a healthy, balanced diet rich in fruits and vegetables is more than enough to maintain optimal vitamin C levels. However, athletes undergoing intense, prolonged training, especially in hot conditions, may experience a more notable cumulative loss. In these cases, paying intentional attention to post-exercise nutrition and strategic hydration with electrolyte-rich fluids, alongside whole foods, is recommended to support recovery and overall performance.

Explore the latest research on sports nutrition from reputable sources like PubMed Central.

Frequently Asked Questions

For most individuals with a healthy, balanced diet, the small amount of vitamin C lost in sweat is easily replenished through food intake and does not require special attention. The loss is considered negligible for the general population.

Water-soluble vitamins, including vitamin C and B-complex vitamins, are lost in sweat, along with minerals like sodium, chloride, potassium, magnesium, and calcium. The amount of vitamins lost is typically small.

While athletes don't necessarily have a higher daily requirement, their needs may increase during periods of intense training due to higher oxidative stress and demand for tissue repair. A diet rich in fruits and vegetables is usually sufficient, but some may benefit from supplementation to support recovery.

Water-soluble vitamins like vitamin C are not stored in the body and are more easily excreted through urine and, to a lesser extent, sweat. Fat-soluble vitamins are stored in fat and the liver, so they are not lost in sweat and are eliminated much more slowly.

The most natural and cost-effective way is through a whole-food diet. Excellent sources of vitamin C include oranges, strawberries, and broccoli, while other nutrients can be found in bananas, nuts, and leafy greens.

Some research suggests that extremely high doses of antioxidants like vitamin C might interfere with the body's natural adaptive responses to exercise, which are beneficial for fitness gains. Strategic and moderate intake is generally recommended over megadoses.

For most everyday activities, water is sufficient. However, for prolonged or intense exercise, especially in heat, sports drinks containing electrolytes and carbohydrates can help replenish significant losses and aid rehydration. Pairing water with electrolyte-rich foods is also effective.