The 7 Best Vitamin C Supplements of 2023

Is a Vitamin C Supplement Beneficial?

Your body cannot make vitamin C, so it has to come from food or supplements. Supplements are effective at increasing blood levels of the vitamin in those that don’t consume enough through food. While consuming extra vitamin C is unlikely to offer benefits in healthy people, vitamin C supplements may help some people reach the recommended 75 milligrams (for women) to 90 milligrams (for men) per day for adults.

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.

In general, the following populations may benefit from a vitamin C supplement:

Those that don’t eat a balanced diet. If you don’t eat many fruits and vegetables, a supplement may be helpful or even necessary.

Smokers. Smokers need an additional 35 mg of vitamin C per day, so if you don’t get that from food, a supplement may be helpful.

People with digestive or malabsorptive disease. Digestive diseases can reduce vitamin absorption as can some cancer treatments and dialysis for kidney disease. Vitamin C supplements can be helpful in increasing blood levels of the vitamin.

Endurance athletes. While vitamin C supplements have not been shown to prevent colds in the general healthy population, some research suggests benefits during periods of intense exercise among endurance athletes.

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

"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.

Those that eat a balanced diet. If you eat fruits and vegetables or drink orange or other fortified juices, it’s unlikely a supplement will offer much benefit. A half-cup of red peppers, six ounces of orange juice, or a large orange can provide all the vitamin C you need. Most fruits and vegetables offer some vitamin C, so if you don’t eat those foods but eat a variety of other produce, you’re likely getting enough from your diet.

In addition, supplements are not designed to replace a healthy diet. If you rely on supplements to get your vitamins, you may miss out on all of the benefits of eating nutrient-rich foods. Research suggests that the sum of all of the nutrients found in food is greater than the individual vitamins on their own as they are in supplements.

Those prone to kidney stones or taking certain medications. “Those that are prone to kidney stones or taking medications like statins, chemotherapy treatments, blood thinners, or estrogen should talk to their healthcare provider first to prevent possible interaction or negative side effects,” says Stark.

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.

How We Select Supplements

Our team works hard to be transparent about why we recommend certain supplements; you can read more about our dietary supplement methodology here. 

We support supplements that are evidence-based and rooted in science. We value certain product attributes that we find to be associated with the highest quality products. We prioritize products that are third-party tested and certified by one of three independent, third party certifiers: USP, NSF, or ConsumerLab. We consulted expert Beth Stark, RDN, LDN to help us choose the supplements on this list.

It's important to note that the FDA does not review dietary supplements for safety and effectiveness before they go to market. Our team of experts has created a detailed, science-backed methodology to choose the supplements we recommend.

What to Look For

Third-Party Testing

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:

1. 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.
2. 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. 
3. The third party certifications we can trust are: ConsumerLab, NSF, and USP. However, these certifications are difficult to obtain and/or expensive for manufacturers, so many companies choose not to get their products tested by one of these three organizations. 
4. Sometimes products tested by these three companies are more expensive to try to offset the cost they pay for certification.
5. Just because a supplement is not tested by one of these three companies, it does not mean it’s a bad product. We recommend doing some research on the reputability of the manufacturer, and calling up the manufacturer and their testing lab to determine their protocols and decide if you feel comfortable consuming the supplement.
   

Form

Vitamin C supplements are available in capsule, gummy, chewable, powder, and liquid form. Gummy, chewable, powder, and liquid versions sometimes contain added sugar, so check ingredients if you’re watching your sugar or carbohydrate intake.

The most common form of vitamin C in supplements is called ascorbic acid. However, it also comes in other forms including sodium ascorbate, Ester-C®, food-based forms, and rose hips. In general, there is no significant difference in these forms as far as how the body is able to use the vitamin C.

Some brands offer something called liposomal encapsulated vitamin C, which small studies have shown may increase the amount that the body is able to use. But it may not be worth the additional cost since doses in supplements are typically significantly higher than the amount your body needs, so your body can likely get enough from other supplement forms.

Ingredients & Potential Interactions

It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included, relative to the recommended daily value of that ingredient. Please bring the supplement label to a healthcare provider to review the different ingredients contained in the supplement and any potential interactions between these ingredients and other supplements and medications you are taking.

Vitamin C supplements may interact with statins and chemotherapy drugs, potentially reducing their effectiveness. If you are undergoing cancer treatment or take any cholesterol-lowering medications, talk to your healthcare provider before starting a supplement.

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.

Some vitamin C supplements contain digestive enzymes, probiotics, and adaptogenic herbs, all of which may come with different risks and side effects, so be sure to check with a healthcare provider before starting a supplement with any of these ingredients.

Vitamin C Dosage

The amount you need will vary depending on age, gender, lifestyle choices like smoking, and other health conditions. The Recommended Dietary Allowance (RDA) for vitamin C is 75 milligrams for women and 90 milligrams for men over the age of 18. Pregnant women need 85 milligrams and breastfeeding women need 115 milligrams.

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).  

How Much Is Too Much?

Although vitamin C is water soluble and your body will get rid of any extra that you consume from food, too much vitamin C in the form of supplements can cause problems. For those who are 19 or older, the National Institute of Health notes a tolerable upper limit (UL) — or the amount you shouldn’t exceed —as 2,000mg per day.