nutrition

What Is the Form of Best Vitamin C for Absorption? The Science Explained

Dr. Carla Montrond Correia ND, CNS

Medically reviewed by

Dr. Carla Montrond Correia ND, CNS

6 min read

a photo of different slices of citrus fruits against light to make them translucent

Vitamin C supplements can help support your health. So, how do you choose the right one? Read on to learn more.

Vitamin C is a water-soluble vitamin that’s found in some foods. It’s added to other foods and is available in supplemental form. It’s an essential vitamin, which means that your body doesn’t make it on its own; it must be consumed from the outside. Vitamin C is mainly found in fruits and vegetables, such as peppers, citrus fruits, broccoli, strawberry, kiwi, and acerola cherries. You also can’t go wrong with a big glass of orange juice.

What does vitamin c do in the human body?

Vitamin C plays a vital role in the health of your body. It helps maintain a healthy immune system, while also helping your body fight off seasonal lung and sinus issues. As an antioxidant, it protects cells against potential damage caused by free radicals. It also plays a key role in facilitating iron absorption. Furthermore, vitamin C helps your body produce collagen, l-carnitine, and some neurotransmitters.

Who would benefit from taking a vitamin C supplement

Vitamin C deficiency is not uncommon, and it typically arises for those who, for whatever reason, have seen a decline in their vitamin C intake. Vitamin C deficiency can also occur in those who are experiencing an increased need for vitamin C without increasing consumption. Some people who are at heightened risk for vitamin C deficiency include:

  • Those who don’t eat the recommended daily servings of fruits and vegetables
  • Those with existing digestive issues
  • Those taking iron supplements
  • Those who smoke
  • Those taking certain medications
  • Older adults
  • Those with certain food allergies

Whether or not you fall into any of these categories, you can talk to a medical professional about your vitamin C levels.

Who would not benefit from a vitamin C supplement

While vitamin C has relatively low toxicity, there are still some groups of people who may want to avoid taking a vitamin C supplement. Some of these groups include:

  • Those with blood disorders
  • Those with excess iron, since vitamin C enhances absorption
  • Those who concerns about blood sugar levels, since vitamin C can increase such levels

If you have concerns about whether you belong to any of these groups, check with a medical professional before deciding on vitamin C supplementation.

Forms of vitamin C supplements

Vitamin C supplements are available in many forms, giving you a variety of options to choose from. You can choose what will work best for you. Some of these forms include:

  • Liquid
  • Chewable
  • Capsule
  • Gummy
  • Powder

If you’re comfortable taking pills – chewable or otherwise – you can check out some encapsulated vitamin C supplements. But if you’d rather mix your supplement into a beverage, the liquid and powdered products might be best for you.

Care/of offers easy-to-digest vitamin C capsules, formulated for easy absorption. We generally recommend you take our supplement with a meal. (More on that below.)

What form of vitamin C is best absorbed?

In general, food sources of vitamin C are better absorbed than supplemental sources. However, in terms of the bioavailability of vitamin C in human subjects, studies have found only very small differences – small enough to have almost no physiological impact. One study did find that kiwi-derived vitamin C was slightly more bioavailable than synthetic vitamin C. Again, though, it’s unclear that this difference would have a physiological impact.

Purest form of vitamin C

The purest form of vitamin C is ascorbic acid.

Quality of vitamin C

When you’re thinking about upping your vitamin C intake, you’ll want to make sure you’re getting high quality, highly absorbable vitamin C. If possible, start with food sources, since those have the highest bioavailability.

Now let’s talk about supplementation. As a general rule, high-quality supplements will include expert formulations and be transparent about sourcing. You should also think about the brand: Is your supplement coming from a popular brand, or is it from a new, untested company? Some companies, like Care/of, test their supplements for purity to ensure that’s what on the label is actually in the supplement – and some, like Care/of, employ third-party testers.

You should also look to see if your supplement choice is free of artificial colors, added sugars, or artificial sugars, all of which dilute the supplement’s effectiveness. Be mindful, too, of whether the supplement is vegan or gluten-free, if these are concerns for you. Care/of’s vitamin C is vegan, gluten-free, third-party-tested, and non-GMO.

Dosage of vitamin C

Vitamin C supplements come in a variety of doses. For healthy adults, the recommended daily allowance (RDA) is 90 mg for men and 75 mg for women. The RDA goes up to 85-120 mg for those who are pregnant or breastfeeding.

For those who are vitamin C deficient, though, a higher dose might be a good idea. In such a scenario, a concentrated supplement is the most efficient option. Care/of’s vitamin C supplement, for example, comes in 250 mg capsules.

In general, you should only take high doses of 1,000 mg or above if recommended by a doctor.

Can you take too much vitamin C?

Vitamin C has low toxicity and generally won’t result in serious side effects if taken in a high dose. Some common potential side effects are diarrhea, nausea, abdominal cramps, and some other gastrointestinal problems. Because of its role in facilitating iron absorption, excessive vitamin C intake could theoretically lead to excess iron absorption. However, among healthy individuals this concern has not been borne out in the research. The tolerable upper limit of vitamin C is 2,000 mg per day.

When to take vitamin C

You can take vitamin C any time of day! If you’re taking a vitamin C supplement, though, it might be best to take it when you take your other supplements. Consistency is the key.

Best way to take vitamin c for absorption

To ensure maximal absorption, the best way to take your vitamin C is with a meal. Again, consistency is key. If there’s a meal you like to take your other supplements with, try incorporating your vitamin C supplement into the mix.

Possible side effects and contraindications

Some possible side effects from vitamin C supplementation include headaches, flushing, nausea or vomiting, and dizziness (mainly from IV use). Major amounts of vitamin C can also increase the risk of kidney issues.

Final takeaways

Vitamin C is an important nutrient for your body, performing a range of important functions. It’s linked to many health benefits, including helping immunity, improving iron absorption, enabling collagen formation, and boosting antioxidant levels. Dietary vitamin C is the most absorbable, but supplemental vitamin C is almost equally so. When selecting a vitamin C supplement, be sure to consider form and quality. Talk to a medical professional about the right plan for you.

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