Debunking the Myth: Can you get vitamin C from the sun?

October 6, 2025 •

3 min read

While many people believe they can absorb vitamins directly from sunlight, a common dietary misconception is that sun exposure provides vitamin C. The truth is that humans must rely on dietary intake for this essential nutrient. So, can you get vitamin C from the sun? The short answer is no, and understanding why is key to proper nutrition.

Quick Summary

The sun does not provide vitamin C, a nutrient sourced only from diet or supplements. Sunlight synthesizes vitamin D in the skin, a fact often confused with how the body obtains vitamin C.

Key Points

Sunlight and Vitamin C: It is a myth that sunlight is a source of vitamin C; our bodies do not produce it in response to sun exposure.
The Sun-Vitamin D Link: Sunlight enables the body to synthesize vitamin D through a separate biochemical process involving cholesterol in the skin.
Dietary Necessity for Vitamin C: Humans must obtain vitamin C from food or supplements because we lack the enzyme required for its internal production.
Best Vitamin C Sources: Beyond citrus, excellent dietary sources of vitamin C include bell peppers, broccoli, kiwi, strawberries, and other fruits and vegetables.
Water-Soluble vs. Fat-Soluble: Vitamin C is water-soluble and not stored in the body, necessitating daily intake, unlike fat-soluble vitamin D which is stored.
Vital Functions: Vitamin C is critical for collagen formation, immune defense, and acting as an antioxidant.
Preventing Deficiency: Relying on the sun for vitamin C can lead to deficiency, with severe cases resulting in scurvy.

The Sun's True Vitamin Synthesis

The sun plays a vital role in synthesizing vitamin D, which is essential for health, but this process is distinct from how the body obtains vitamin C. When skin is exposed to ultraviolet B (UVB) rays, a chemical reaction occurs involving a cholesterol derivative in the skin. This produces previtamin D3, which then converts to vitamin D3. Unlike water-soluble vitamin C, vitamin D is fat-soluble and can be stored in the body. However, factors such as skin tone, location, time of day, and sunscreen use impact vitamin D production from sunlight. Moreover, excessive sun exposure to maximize vitamin D can increase the risk of skin cancer and premature aging.

Why Humans Can't Synthesize Vitamin C

Humans cannot produce their own vitamin C (ascorbic acid) because of a genetic mutation that led to the loss of the enzyme L-gulonolactone oxidase. This enzyme is crucial for the final step of vitamin C synthesis from glucose. Consequently, humans must obtain vitamin C from external sources, making it an essential dietary nutrient. This lack of internal production is why the sun cannot provide us with vitamin C.

The Critical Functions of Vitamin C

Vitamin C is essential for preventing scurvy and plays many other vital roles:

Collagen Synthesis: It's necessary for producing collagen, which maintains healthy skin, bones, and blood vessels. A deficiency impairs connective tissue formation.
Antioxidant Protection: Vitamin C protects cells from damage by free radicals linked to aging and disease.
Immune System Support: It helps the immune system function correctly and protects white blood cells from damage.
Iron Absorption: Vitamin C improves the absorption of nonheme iron from plant foods.

Dietary Sources of Vitamin C

Since the sun isn't a source, getting enough vitamin C depends entirely on diet or supplements. While oranges are known for vitamin C, many other fruits and vegetables are excellent or even richer sources.

Good dietary sources include:

Vegetables: Bell peppers, broccoli, Brussels sprouts, kale, cauliflower, tomatoes, cabbage.
Fruits: Strawberries, kiwi, guava, cantaloupe, papaya, pineapple.

Making Sense of It All: Vitamin C vs. Vitamin D

Understanding the differences between these two vitamins is key:


Feature	Vitamin C (Ascorbic Acid)	Vitamin D (Calciferol)
Source	Found in fruits and vegetables; must be consumed through diet or supplements.	Produced in skin from sunlight (UVB); found in fortified foods and supplements.
Body Production	Cannot be synthesized by humans.	Synthesized in skin with UVB exposure.
Solubility	Water-soluble; excess is excreted.	Fat-soluble; stored in the body.
Absorption	Absorbed into bloodstream via small intestine.	Absorbed via lymphatic system after breakdown.
Storage	Not stored; requires daily intake.	Stored; toxicity possible with excessive supplements.
Primary Function	Collagen synthesis, immune function, antioxidant.	Calcium absorption, bone health, muscle function.

Conclusion: The Takeaway for Your Diet

The idea that the sun provides vitamin C is a myth. While sunlight aids vitamin D production, vitamin C must come from your diet. Ensure adequate intake by eating a variety of fruits and vegetables. Supplements are an option for those with dietary restrictions. A balanced approach to sun exposure for vitamin D, coupled with skin protection, is recommended. Knowing how your body gets each vitamin allows for better health choices.

For more authoritative information on Vitamin D synthesis and health, consult the National Institutes of Health's Office of Dietary Supplements fact sheets.

Frequently Asked Questions

Yes, sunlight is a primary source for the body's synthesis of vitamin D, which is essential for bone health and immune function.

Humans lack the enzyme L-gulonolactone oxidase, which is necessary for the final step in the synthesis of vitamin C from glucose. This makes us dependent on external dietary sources.

Vitamin C is water-soluble, meaning the body cannot store it, and any excess is excreted. In contrast, vitamin D is fat-soluble and can be stored in the body's fat and liver.

Most people can get enough vitamin C from a varied and balanced diet rich in fresh fruits and vegetables. If you have specific dietary limitations, a supplement may be beneficial.

While citrus fruits are an excellent source, other foods like red peppers, kiwi, and broccoli actually contain higher concentrations of vitamin C per serving.

Excessive sun exposure increases the risk of skin cancer, photoaging, and potential damage to the skin, eyes, and immune system. It's crucial to balance sun exposure with protective measures.

Early signs can include fatigue, muscle aches, and dry skin. Severe deficiency can lead to scurvy, causing bleeding gums, poor wound healing, easy bruising, and joint pain.