Not all third-party testing is created equal. It is not uncommon for supplement companies to pay labs for certificates after conducting minimal to no testing.

Wang K, Jiang H, Li W, Qiang M, et al. Role of vitamin C in skin diseases. Frontiers in Physiology. 2018;9. doi:10.3389/fphys.2018.00819 When shopping for a vitamin C supplement, you’ll want to consider quality, dose, and price. You’ll also want to decide on the form of supplement you’re interested in, such as chewable tablets or a powder. Quality Some people take high doses of vitamin C to boost the immune system, especially during cold and flu season. “Vitamin C is often thought of as a miracle immune-booster, but this isn’t the case,” says Stark. In fact, research suggests that vitamin C supplements don’t prevent colds unless you are exposed to extremely cold temperatures. regularly engage in extreme exercise, or have low vitamin C intake or absorption. They may slightly reduce a cold's duration or severity if taken regularly before the cold starts (but not after symptoms arise). Research has also shown that vitamin C supplements do not help prevent or treat COVID.Medical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy. Böttger, F., et al. (2021). High-dose intravenous vitamin C, a promising multi-targeting agent in the treatment of cancer. Johnston CS, Barkyoumb GM, Schumacher SS. Vitamin C supplementation slightly improves physical activity levels and reduces cold incidence in men with marginal vitamin C status: A randomized controlled trial. Nutrients. 2014; 6(7):2572-2583. https://doi.org/10.3390/nu6072572 The NIH suggests that vitamin C may help reduce a person’s chance of developing heart conditions, as it helps widen blood vessels and increase nitric oxide production, but more research is needed.

Additionally, a systematic review found that vitamin C supplementation was effective in lowering blood pressure in people with hypertension ( 5).If you’re eating a balanced diet rich in nutritious ingredients, like fruits and vegetables, taking a vitamin C supplement likely isn’t necessary. Vitamin C is sometimes combined with zinc and marketed for immune health, but research doesn’t actually support these claims. Too much zinc (more than 40 milligrams for adults) can also lead to nausea, vomiting, and other negative health effects, so be mindful about amounts found in supplements. You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch. Those that take other supplements. If you take a multivitamin or other supplement that contains vitamin C, taking additional vitamin C is unnecessary and may even lead to negative side effects like nausea, vomiting, or diarrhea.

https://diabetesjournals.org/care/article/44/2/618/35482/Effects-of-Vitamin-C-Supplementation-on-Glycemic Third party testing does not test to see if a product is effective or safe for everyone, and it does not ensure the supplement will not interact with other supplements or medications.Research on vitamin C supplements in helping prevent or treat chronic diseases is inconclusive. Studies show a role of vitamin C in treating cancer, cardiovascular disease, and type 2 diabetes; however, there is not enough evidence to support taking high dose supplements or aiming to get more than the adequate amount. Research does support eating more fruits and vegetables to prevent and manage chronic disease, so reach for an extra serving of produce before you grab supplements. Who May Not Benefit from Vitamin C Supplements To ensure that a product contains what it says it does, it’s best to look for one that’s tested by a third-party organization, such as United States Pharmacopeia (USP), Consumer Lab, or NSF International. Mineral ascorbates, such as sodium ascorbate or calcium ascorbate, are less acidic and may be preferable by people who experience digestive side effects when taking regular ascorbic acid. However, there is limited research on whether these forms are actually more well-tolerated ( 16). However, some believe that taking very large doses of vitamin C, or “megadosing,” is beneficial. This may stem from a 1976 paper indicating that high dose vitamin C could prolong the lives of people with terminal cancer. Many manufacturers include more than the RDA since the amount your body absorbs may be less than what is provided in the supplement. However, be sure that the amount included does not exceed the tolerable upper limit (2,000 mg per day for those 19 and older).

When taken as recommended, vitamin C supplements are generally safe for most healthy people,” says Stark. However, that doesn’t mean that you need a supplement. This medicine may affect certain lab tests. Tell all of your health care providers and lab workers that you take ascorbic acid (vitamin C) solution, liquid, and syrup. The Megafood Complex C supplement meets many of our standards for a high quality supplement. It provides a solid 250 milligram dose of vitamin C. Megafood vitamins are not third party verified, but they are certified Non-GMO and vegan and free of common allergens, making them suitable for most people. MegaFood is also a certified B Corporation, meaning they prioritize social and environmental well-being in their business practices. According to the NIH, the recommended daily vitamin C intake for most non-lactating adults is 75–90 milligrams (mg). Can vitamin C damage the kidneys?

Some professional-grade brands can be expensive, but keep in mind that a higher price doesn’t necessarily mean a better product. Supplements that are third-party tested are sent to a lab where they are tested to ensure they contain what they say they contain and are not contaminated with specific high-risk, common contaminants. However, it’s important to note: For those that have trouble swallowing a capsule, a spray like the Garden of Life MyKind Organics Tangerine Spray may be a good choice. It’s easy to consume, doesn’t contain any added sugars or other sweeteners, and is free from major allergens and gluten.