What vitamins are lost in sweat? And how to replenish them.

October 12, 2025 •

5 min read

An average person can sweat between 0.8 and 1.4 liters of fluid per hour during exercise. While many focus on replacing fluids and electrolytes, it's also important to know what vitamins are lost in sweat, which include key water-soluble nutrients essential for energy and health.

Quick Summary

Water-soluble vitamins, particularly B-complex and vitamin C, can be excreted through sweat during intense physical activity or in hot environments. This article outlines which vitamins are lost, their functions, and offers strategies for effective nutritional replenishment through diet.

Key Points

Water-Soluble Vitamins are Excreted: Water-soluble vitamins (B-complex and C) are the vitamins primarily lost through sweat, as the body does not store them for long periods.
B-Vitamins are Essential for Energy: Intense exercise and heat can increase the loss of B-complex vitamins, which are vital for converting food into energy.
Vitamin C Offers Antioxidant Protection: This vitamin's antioxidant properties are crucial for mitigating oxidative stress during physical activity, and it is also lost through sweat.
Electrolytes are Lost in Higher Concentrations: While the focus is on vitamins, electrolytes like sodium, potassium, and magnesium are lost in much greater amounts and are critical for hydration and muscle function.
Dietary Replenishment is Key: The best way to replace lost nutrients is through a balanced diet rich in fruits, vegetables, whole grains, and lean proteins.
Consider Supplements for High Needs: For serious athletes or those with diagnosed deficiencies, targeted supplementation may be necessary to maintain optimal levels, but should be discussed with a professional.
Excessive Sweating Can Signal a Deficiency: A sweaty head or other forms of excessive sweating could be an early indicator of a vitamin D deficiency.

The Science Behind Sweat and Nutrient Loss

Sweating is your body's natural cooling mechanism. When your core body temperature rises due to exercise or heat, your sweat glands release moisture to the skin's surface. As this moisture evaporates, it carries heat away, helping to regulate your temperature. While sweat is primarily water and sodium chloride, it also contains small amounts of other minerals and water-soluble vitamins.

Unlike fat-soluble vitamins (A, D, E, and K), which are stored in the liver and fatty tissues, water-soluble vitamins (B-complex and C) are not stored in significant amounts and are eliminated more quickly through sweat and urination. During periods of heavy or prolonged sweating, such as during intense training or in hot climates, the continuous loss of these water-soluble vitamins and certain minerals can impact your body's functioning.

The Water-Soluble Vitamins Lost in Sweat

Several water-soluble vitamins are known to be lost in sweat. While the quantities are generally small, their consistent depletion during intense activity makes replenishment important, especially for athletes.

B-Complex Vitamins: This group includes thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate (B9), and cobalamin (B12). B vitamins are crucial coenzymes involved in cellular energy production. Intense exercise increases energy demand, and studies suggest that athletes may lose more B vitamins, such as riboflavin (B2) and vitamin B6, through sweat. While B12 loss in sweat is minimal, prolonged insufficient intake can lead to deficiency.
- Thiamin (B1): Vital for converting carbohydrates into energy.
- Riboflavin (B2): Works with other B vitamins in energy metabolism.
- Pantothenic Acid (B5): Contributes to normal energy-yielding metabolism.
- Pyridoxine (B6): Involved in protein and carbohydrate metabolism.
Vitamin C: As a powerful antioxidant, vitamin C helps protect cells from oxidative stress caused by exercise. Studies on heat-exposed workers have shown measurable losses of vitamin C in sweat, correlating with factors like blood pressure. Vitamin C also plays a role in immune function, particularly during and after extreme physical activity.

Essential Minerals (Electrolytes) Also Lost in Sweat

While not vitamins, electrolytes are critical for hydration and bodily functions and are lost in higher concentrations in sweat. Replenishing these is just as, if not more, important for maintaining performance and health.

Sodium and Chloride: These are the most abundant electrolytes in sweat. They are crucial for maintaining fluid balance, nerve impulses, and muscle contractions.
Potassium: Key for muscle function and regulating fluid balance. Intense exercise can lead to notable losses, and some studies suggest an inverse relationship between sweat potassium loss and blood pressure.
Magnesium and Calcium: Both are vital for muscle function and energy metabolism. Magnesium is lost through sweat, and deficiency can increase stress, potentially leading to more sweating. Calcium loss through sweat can also occur and may be influenced by exercise.

How to Replenish Lost Vitamins and Minerals

Replenishing lost nutrients is best achieved through a balanced diet, but supplements can play a role for high-performance athletes or those with specific deficiencies.

Dietary Replenishment

For B-Vitamins: Consume a variety of meats, eggs, dairy, leafy green vegetables, nuts, and legumes. Whole grains are also excellent sources.
For Vitamin C: Citrus fruits (oranges, grapefruit), strawberries, spinach, and broccoli are rich sources.
For Electrolytes: Seek out fruits (bananas, avocados, watermelon), vegetables (spinach, sweet potatoes), dairy products (yogurt, milk), and salted snacks. Homemade electrolyte drinks with diluted fruit juice and a pinch of salt are a great option.

Strategic Hydration and Supplementation

Hydrate Consistently: Drink water throughout the day, not just during exercise. For intense sessions over an hour, consider a sports drink containing carbohydrates and electrolytes, especially sodium.
Post-Workout Nutrition: A balanced recovery meal or snack containing carbohydrates, protein, and fluids is ideal. Foods like yogurt with fruit, or a turkey sandwich on whole-grain bread, are effective.
Consider Supplements: For individuals with diagnosed deficiencies or extremely high training loads, a B-complex or vitamin C supplement can be beneficial. Always consult a healthcare professional before starting supplementation to ensure proper dosage.

Comparison: Water-Soluble vs. Fat-Soluble Vitamins

Understanding the fundamental difference between these two vitamin types is key to understanding nutrient loss through sweat.


Feature	Water-Soluble Vitamins	Fat-Soluble Vitamins
Types	B-complex (Thiamin, Riboflavin, Niacin, etc.), Vitamin C	A, D, E, and K
Storage	Stored in the body in very limited amounts; excess is excreted.	Stored in the liver and fatty tissues; eliminated much more slowly.
Loss in Sweat	Present in small amounts in sweat and can be lost during exercise.	Not lost via sweat; typically not significantly impacted by perspiration.
Replenishment	Requires regular replacement, especially with increased fluid loss.	Intake is more stable; regular replenishment is not directly tied to fluid loss.
Key Functions	Energy metabolism, immune function, cell protection.	Vision, bone health, immune function, blood clotting.

Conclusion

While the total amount of vitamins lost in sweat is minimal compared to minerals, consistent losses of water-soluble vitamins like B-complex and vitamin C during heavy or prolonged sweating can impact your body's nutrient balance over time. For athletes and individuals who sweat profusely, maintaining a diet rich in a variety of fruits, vegetables, lean proteins, and whole grains is the most effective way to ensure optimal nutrient levels. Combining this with proper hydration, especially electrolyte-rich fluids for intense activities, is the best strategy for performance and overall health. Consulting a registered dietitian or healthcare provider can provide personalized nutritional guidance.

The Importance of a Personalized Nutrition Plan

Nutritional needs vary significantly based on factors like genetics, exercise intensity, climate, and overall health status. For those with high sweat rates, a generic approach to hydration and nutrition may not be sufficient. Paying attention to your body's signals, monitoring your performance, and adjusting your intake of vitamins and minerals accordingly is crucial. Proper replenishment isn't just about recovering from exercise, it’s about maintaining long-term health and preventing deficiencies that can manifest as fatigue, poor performance, and other health issues.

The Role of Vitamin D in Sweating

An interesting connection exists between sweating and vitamin D. Excessive sweating, particularly on the head, can be an early sign of a vitamin D deficiency. Since vitamin D plays a role in temperature regulation, low levels can cause the body to overcompensate with increased sweating. This highlights the complex relationship between nutrients and bodily functions and the importance of a comprehensive nutritional approach. In addition to diet, getting safe sun exposure can help maintain healthy vitamin D levels.

International Society of Sports Nutrition Position Stand: nutrient timing

Frequently Asked Questions

Failure to replace lost nutrients, especially in individuals with high sweat rates, can lead to dehydration, muscle cramps, fatigue, and decreased athletic performance. Long-term deficiencies can cause more serious health issues.

No, fat-soluble vitamins (A, D, E, and K) are not lost in sweat. They are stored in the body's liver and fatty tissues and are eliminated very slowly over time.

Yes, excessive or prolonged sweating can lead to a depletion of water-soluble vitamins and important electrolytes over time, potentially resulting in a deficiency if not adequately replenished through diet.

For most light exercise, water is sufficient. However, for intense or prolonged exercise lasting more than an hour, a sports drink can help replace the sodium, electrolytes, and carbohydrates lost in sweat.

Foods rich in water-soluble vitamins and minerals include bananas, avocados, leafy greens (like spinach and kale), sweet potatoes, nuts, seeds, and dairy products. Citrus fruits and berries are excellent sources of Vitamin C.

Symptoms can include persistent fatigue, muscle weakness or cramps, and decreased athletic performance. Excessive sweating, especially from the head, can also be an early sign of a vitamin D deficiency.

Yes, sweat rates can vary dramatically between individuals due to factors like body mass, genetics, heat acclimation, fitness level, and environmental conditions. This means some people lose more fluid and nutrients than others and may need to adjust their intake accordingly.