Immunotherapy has revolutionized cancer treatment by using the body’s immune system to fight cancer cells. However, not all patients respond to this treatment, and researchers are constantly exploring ways to make it more effective. Recent studies have shown that vitamin C, when given intravenously at high doses, may provide a significant boost to immunotherapy.

The Power of Vitamin C:

Vitamin C has long been a topic of debate when it comes to its anticancer effects. Previous studies focused on its direct impact on tumors, but they often used mice with compromised immune systems. However, a new study by Magri et al. took a different approach by studying mice with fully functional immune systems. Their findings shed light on how vitamin C interacts with the immune system and immunotherapy.

Supporting the Immune Response:

The study revealed that a strong immune system is essential to maximize the anticancer effects of vitamin C. In various types of tumors, such as breast, colorectal, melanoma, and pancreatic cancers, vitamin C was found to enhance the immune response. It achieved this by increasing the infiltration of immune cells into the tumor microenvironment, leading to a slowdown in cancer growth. The effects were particularly dependent on the presence of T cells, which play a crucial role in immune responses.

Cooperation with Immunotherapy:

Vitamin C not only boosted the activity of CD8 T cells, known for their role in killing cancer cells, but it also showed cooperation with immune checkpoint therapy (ICT). ICT uses antibodies to target specific molecules and has shown success in treating certain cancers. However, only a subset of patients benefits from this therapy. The combination of vitamin C and ICT proved to be promising, even in tumors with a high mutational burden that typically do not respond well to immunotherapy alone.

Implications for Future Research:

The results of this study provide a strong rationale for conducting clinical trials that combine high-dose vitamin C with immunotherapy. While vitamin C deficiency has been linked to impaired immunity, this research highlights its potential in boosting the immune response against cancer.


Vitamin C has shown promise as a valuable addition to immunotherapy. By enhancing the immune response and cooperating with immunotherapy, it may improve treatment outcomes for cancer patients. Although more research is needed to fully understand its benefits and optimize its use, these findings open up new possibilities for combination therapies. As we continue to explore the potential of vitamin C in cancer treatment, we may unlock new strategies to enhance the effectiveness of immunotherapy and provide hope to a broader range of patients.