Effects of Taking Vitamin C and D Together on Your Body

Medically reviewed by Alex Yampolsky, PharmD

• Taking vitamin C and D together is generally safe if you stay within the recommended doses.

• Vitamin C and D supplements may enhance immune health and strengthen bones.

• Exceeding the recommended doses of vitamin C or D can lead to side effects like nausea or diarrhea.

Vitamin C and D can be taken together without concerns about interactions. This combination has several potential benefits for your health.

1. Strengthen Immune Support

Obtaining sufficient amounts of vitamin C and D is crucial for a robust immune system. Vitamin C supplements have been shown to enhance immune function and may help ward off infections, including viral illnesses.

Meanwhile, vitamin D plays a significant role in modulating the immune response and reducing inflammation, contributing to your body’s defenses against infection.

Given their combined immune-boosting properties, taking both vitamins may substantially improve your ability to fend off infections.

2. Enhance Resistance to Viral Infections

Several studies suggest that vitamin C possesses antiviral properties. Regular intake of vitamin C may help shorten the duration of common colds.

Vitamin D also lowers the risk of viral infections by bolstering physical barriers, such as the skin and mucous membranes, against pathogens.

Additionally, vitamin D may mitigate the risk of respiratory infections in both children and adults.

3. Accelerate Wound Healing

Research indicates that vitamin D promotes the regeneration of skin cells, which enhances wound repair and minimizes scarring.

Vitamin C plays a vital role in wound healing as well, with studies suggesting it boosts the production of factors essential for recovery. Together, vitamins C and D could facilitate quicker healing.

4. Support Bone Health

A deficiency in both vitamin C and D may lead to diminished bone mineral density and an increased risk of osteoporosis, particularly prevalent among older adults.

Studies suggest that combining both vitamins can help hinder bone loss and foster stronger bones.

Furthermore, taking vitamins C and D may offer additional protection against osteoporosis and fractures.

5. Mitigate Chemotherapy Complications

Vitamin C and D supplementation may improve health outcomes for individuals undergoing chemotherapy.

One study found that both vitamins were associated with fewer complications for patients with leukemia. Although more research is necessary, these preliminary findings are promising.

What Are the Recommended Dosages?

The recommended daily intake of vitamin D varies based on age and pregnancy status, as follows:

• 14 years and under: 10-15 micrograms (mcg), or approximately 400-600 international units (IU).

• Age 14 to 70: 15 mcg (600 IU).

• Age 70 and older: 20 mcg (800 IU).

• During pregnancy: 15 mcg (600 IU).

Recommended daily amounts of vitamin C, based on age and pregnancy status, are as follows:

• 0 to 6 months: 40 milligrams (mg).

• 14 to 18 years: 65–75 mg.

Smokers often require an additional 35 milligrams of vitamin C compared to non-smokers.

Excessive vitamin C intake can cause diarrhea, nausea, and abdominal cramps; however, doses of up to 2-3 grams daily have proven safe for many. Caution is advised for those with hemochromatosis, as it can exacerbate iron absorption risks.

Consuming excessively high doses of vitamin D—100 micrograms (4,000 IU)—may lead to symptoms such as muscle weakness, nausea, confusion, dehydration, and kidney stones.

Vitamin D can also interact with medications like diuretics and statins; consulting a doctor about your prescriptions is advisable.

Are There Any Side Effects to Consider?