The Skinny on Vitamin C Supplements

January 9, 2024
| Created by Hannah Casey, RDN, CD

Oral vitamin C supplements are often touted as a natural way to cure the common cold. But does the science back up this claim? Here is a rundown on whether expensive vitamin C supplements are worth your time and money.  

Vitamin C is an essential nutrient your body needs to form tissues, protect cells from free radicals, and aid in the healing process. Many people claim in addition to these benefits that it can cure or prevent the common cold. No wonder vitamin C supplements are so popular! Unfortunately, I hate to break it to you, but there is minimal evidence to support such lofty claims. 

Evidence shows that oral vitamin C supplements have at best only a minor influence on the duration and severity of colds. Oral vitamin C supplements may shorten a cold by .5-1 day if taken routinely, not if taken at the onset of cold symptoms. Supplements may have a mild impact on cold symptoms; however, severity is hard to classify from person to person, so results vary. Evidence also shows that vitamin C supplements do not prevent a cold, despite dosage levels and duration of use. 

So, why do we believe that oral vitamin C can prevent or cure the common cold? Vitamin C supplementation was first recommended in the 1970’s. Partly since it doesn’t have any life-threatening side effects when taken in large amounts and partly due to a scientist named Linus Pauling, who believed that vitamin C may be a cure-all for a large array of conditions. This information has been passed down for decades and while we now know vitamin C has minimal at best improvements to a cold, many people still choose to buy them. 

The truth is, most Americans get enough vitamin C from their diet. The recommended amount is about 75-90 mg/day, which you can get from a cup of strawberries or an orange. Vitamin C is found in citrus fruits, berries, tomatoes, peppers, potatoes and a slew of other produceThe bottom line is, if you are eating a healthy, well-balanced diet, you are most likely getting enough vitamin C. Oral supplements often include high doses of vitamin C, well over the recommended daily limit. Side effects from taking too much (>2000 mg/day) supplemental vitamin C may include diarrhea, nausea, vomiting, or bloating. An increased risk of kidney stones has also been associated with vitamin C supplementation (>250 mg) in menIt’s important to note that those who smoke, have certain gastrointestinal conditions, or have a limited diet that excludes fruits and vegetables, may benefit from an oral vitamin C supplementBe sure to contact your healthcare provider to determine if supplementation is right for you.  

If vitamin C doesn’t help prevent or cure the common cold, then what does? As far as prevention, ensure you are washing your hands with soap and water, disinfecting surfaces, and stay away from individuals who are sick. Eating a diet that is well balanced and includes fruits, vegetables, whole grains, and protein will also help your body stay healthy. If you are looking for ways to manage cold symptoms you should stay hydrated with tea, water, or broth. Avoid coffee and alcohol until your symptoms have resolved. Consult your doctor about over-the-counter cold medications to alleviate other symptoms.  

So, save yourself some time and money and skip the vitamin C supplements. Instead, opt for a balanced diet that includes fruit and vegetables and practice good hygiene! If you are looking for additional support, reach out to your Harmons dietitian at