Vitamin C Supplement Effectiveness

Vitamin C Supplement Effectiveness

Crystal Zabka-Belsky
3 minute read

Vitamin C Supplement Effectiveness

Are vitamin C supplements effective?

Yes, Vitamin C supplements can be an effective means of promoting immune health when addressing a deficiency. Having said that, as described by the Harvard School of Public Health (Vitamin C | The Nutrition Source | Harvard T.H. Chan School of Public Health), Vitamin C deficiency is rare in developed countries, making the need for supplementation less likely. However, supplementation is a popular trend and it is important to note that the body has a threshold of need and usage capacity for all vitamins and minerals in the body. Once this threshold is maximized, taking additional megadoses of Vitamin C will not provide additional benefit and could actually do more harm than good. Simply stated, once you have reached the amount of Vitamin C that the body needs by food, supplements, or a combination of the two, additional Vitamin C is very unlikely to protect you any further.

How many vitamin C supplements should people take?

The amount of Vitamin C needed in supplement form is determined by the amount of Vitamin C obtained from food on a daily basis.  According to the Dietary Reference Intakes (Dietary Reference Intakes for Calcium and Vitamin D - NCBI Bookshelf (, adult females need to achieve 75 mg per day, while adult males need 90 mg per day. This amount of Vitamin C can be easily achieved with food intake (Vitamin C - Health Professional Fact Sheet ( For example, ½ cup of raw red bell pepper or one medium orange will provide all of the Vitamin C that both adult females and males need in a day! Eating just ½ cup of cooked broccoli or ½ cup fresh strawberries will get both females and males halfway to their daily goal! 

Are there any downsides to taking vitamin C supplements?

You can definitely get too much of a good thing! As highlighted by the Mayo Clinic (Too much vitamin C: Is it harmful? - Mayo Clinic), exceeding the tolerable upper limit of 2000 mg per day with megadoses of Vitamin C supplementation in an effort to boost the immune system can actually lead to toxicity symptoms such as diarrhea, nausea, vomiting, heartburn, abdominal cramps, headache and insomnia. In addition, reliance on supplements often discourages people from eating whole food sources, reducing their intake of other important nutrients like fiber, vitamins and minerals.

Should everyone be taking vitamin C supplements?

Not necessarily! With a consistent balanced intake, individuals can easily achieve their Vitamin C needs, eliminating the need for supplementation. In today’s fast-paced world, I recommend that individuals refocus their finances on seeking strategies to include wholesome ready-made meals by exploring meal prep delivery services in their area. Money will be better spent on having healthy meals delivered (Clean Eatz Kitchen - Healthy Meals Delivered) than jumping on the supplement bandwagon!


Crystal Zabka-Belsky, MS, RDN, CSSD, LMNT, LDN

Resident Dietitian, Clean Eatz Kitchen


« Back to Blog