Which Is Better for Immunity and Energy?

Posted by AweSamo January 29, 2026
Which Is Better for Immunity and Energy?

Key Takeaways

  • Magnesium helps support energy production by activating ATP.  
  • Vitamin C directly supports immune cells and may shorten cold symptoms.  
  • Talk to your doctor before starting on magnesium or vitamin C supplements.

When your energy is low or you’re getting sick more often, magnesium and vitamin C are two supplements you might consider. While both support overall health, they may influence immune function and energy levels in different ways.

Magnesium Supports Immune Cells

Magnesium is an essential mineral involved in hundreds of processes in the body, some of which support normal immune function. Rather than fighting infections directly, magnesium helps immune cells communicate and keeps inflammation at bay.

Low magnesium levels have been linked to ongoing, low-grade inflammation, which can make immune responses less efficient over time. Research shows magnesium supports immune cells involved in the body’s immediate response and its ability to remember and fight infections over time.

Magnesium also helps maintain a healthy gut microbiome. Because much of the immune system is located in the gut, this support plays an important role in immune defense.

Vitamin C Plays a More Direct Role in Immunity

Vitamin C plays a more direct role in immune defense. It concentrates inside certain immune cells, such as neutrophils, where it helps support functions like movement toward infection sites, engulfing pathogens, and killing microbes.

Vitamin C also acts as an antioxidant, helping protect immune cells from oxidative stress during infections. Low vitamin C levels are associated with impaired immune defense and a higher risk of infections, particularly respiratory infections.

Research shows that regular vitamin C intake does not reliably prevent colds in the general population, but it may slightly shorten the duration and reduce the severity of cold symptoms. These benefits are more noticeable in people with low vitamin C intake or during periods of physical stress.

Taking more vitamin C than the body needs does not further strengthen immunity and may increase the risk of side effects, such as gastrointestinal upset.

Magnesium Supports Cellular Energy Production

Magnesium plays an essential role in how the body makes energy. It is needed to activate ATP, the molecule cells rely on for energy, and without enough magnesium, this process becomes less efficient.

Low magnesium levels can interfere with energy production at the cellular level and may contribute to fatigue. Magnesium also supports normal muscle and nerve function and helps regulate sleep, all of which can affect how energized a person feels during the day.

People with low magnesium intake or higher needs due to stress, intense exercise, or certain health conditions may notice improvements in fatigue when magnesium levels are restored.

Magnesium supports energy production at a basic level. It does not create an immediate energy boost, but helps the body produce and use energy more efficiently over time.

Vitamin C Supports Energy Indirectly

Vitamin C does not directly create energy. Instead, it supports energy metabolism in more indirect ways. It is required for the production of carnitine, a compound that helps transport fatty acids into mitochondria, where they are used to generate energy.

Low vitamin C levels have been associated with fatigue and reduced physical work capacity, likely due to impaired metabolism and increased oxidative stress. Correcting a deficiency may help reduce feelings of tiredness in people with low vitamin C intake.

However, vitamin C does not act as a stimulant, and supplementation is unlikely to increase energy levels in people who already meet their daily needs.

Recommended Daily Amounts

Here’s how much adults typically need per day:

Magnesium:

  • Adult women: 310–320 milligrams
  • Adult men: 400–420 milligrams

Vitamin C:

  • Adult women: 75 milligrams
  • Adult men: 90 milligrams

Supplement Safety and Other Considerations

Magnesium supplements can cause diarrhea or stomach upset, especially at higher doses. People with kidney disease should avoid magnesium supplements unless advised by a healthcare provider.

High doses of vitamin C may cause gastrointestinal discomfort and, in some people, increase the risk of kidney stones.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. National Institutes of Health. Magnesium: Fact Sheet for Health Professionals.

  2. Lima F da S, Santos MQ dos, Makiyama EN, Hoffmann C, Fock RA. The essential role of magnesium in immunity and gut health: Impacts of dietary magnesium restriction on peritoneal cells and intestinal microbiome. J Trace Elem Med Biol. 2025;88:127604. doi:10.1016/j.jtemb.2025.127604

  3. Ashique S, Kumar S, Hussain A, et al. A narrative review on the role of magnesium in immune regulation, inflammation, infectious diseases, and cancer. J Health Popul Nutr. 2023;42(1):74. doi:10.1186/s41043-023-00423-0

  4. Maier JA, Castiglioni S, Locatelli L, Zocchi M, Mazur A. Magnesium and inflammation: advances and perspectives. Semin Cell Dev Biol. 2021;115:37-44. doi:10.1016/j.semcdb.2020.11.002

  5. Carr AC, Maggini S. Vitamin C and immune function. Nutrients. 2017;9(11):1211. doi:10.3390/nu9111211

  6. National Institutes of Health. Vitamin C; Fact Sheet for Health Professionals.

  7. Cepeda V, Ródenas-Munar M, García S, Bouzas C, Tur JA. Unlocking the power of magnesium: a systematic review and meta-analysis regarding its role in oxidative stress and inflammation. Antioxidants. 2025;14(6):740. doi:10.3390/antiox14060740

  8. Oregon State University, Linus Pauling Institute. Magnesium.

  9. Zhang Y, Chen C, Lu L, et al. Association of magnesium intake with sleep duration and sleep quality: findings from the CARDIA study. Sleep. 2022;45(4):zsab276. doi:10.1093/sleep/zsab276

  10. Tardy AL, Pouteau E, Marquez D, Yilmaz C, Scholey A. Vitamins and minerals for energy, fatigue, and cognition: a narrative review of the biochemical and clinical evidence. Nutrients. 2020;12(1):228. doi:10.3390/nu12010228

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By Morgan Pearson, MS, RD

Morgan Pearson is a registered dietitian and health writer with expertise in nutrition, mental health, and fitness. She has several years of experience developing evidence-based health content and enjoys translating complex research into accessible, engaging information.

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