Medically Reviewed

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

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

Vitamin C is an essential nutrient that is popular for its antioxidant benefits and healthy immune system support. It’s naturally found in many foods, but can also be taken as a supplement. When you’re deciding which vitamin C is best for you, it can be confusing to understand the differences between liposomal vitamin C and ascorbic acid, as well as how other forms of the nutrient work in the body. This guide explains the benefits of this important nutrient and how to make the most of it if you choose to take it in a supplement form.

What does vitamin c do in the human body?

Vitamin C is a water-soluble nutrient that is essential for human health. Your body cannot make it, so it has to come from food or supplements. As one of the most researched micronutrients, scientists know that vitamin C plays an important role for many aspects of health, including:

  • Antioxidant defenses to protect cells from free radicals
  • Healthy immune system function
  • Regenerating other antioxidants in the body (including vitamin E)
  • Protein metabolism
  • Making neurotransmitters
  • Collagen production and healthy connective tissue
  • Normal wound healing and tissue recovery
  • Nonheme iron absorption

7 forms of Vitamin C, ranked by absorption

Vitamin C comes in several forms with varying amounts of bioavailability. This means that the body does not necessarily break all of the forms down and absorb them in the same way. More research is needed to understand how each of the forms affects plasma levels of vitamin C in the body.

1. Liposomal Vitamin C

While vitamin C is a water-soluble nutrient, it can be formulated with fat to support how the body receives and uses it. When vitamin C is paired with phospholipids, this is known as a liposomal formulation.

So how does it work? Typically vitamin C from foods or most supplements is broken down in the stomach. But the highly acidic environment of hydrochloric acid may affect how much supplemental vitamin C makes it to the next phase of digestion. To help vitamin C survive through the stomach, its water-soluble molecule is encapsulated in a liposome. This forms a shield around the nutrient, protecting it from the acid, and transporting it into the small intestine. Since most fat digestion takes place in the small intestine, the vitamin C is released there after enzymes from the gallbladder and pancreas facilitate lipid breakdown.

Researchers have found that this form of vitamin C leads to higher circulating concentrations of the nutrient compared to other oral forms that are not liposomal.

Liposomal vitamin C can include phospholipids from different sources. Some common ingredients these dietary supplements may contain include sunflower oil, palm oil, or soybean oil. If you have food allergies, be sure to carefully read labels to know where the lipid ingredients are sourced from.

2. Vitamin C with Bioflavonoids

Many natural sources of vitamin C, like acerola cherries, also contain additional phytonutrients known as bioflavonoids. These compounds further enhance the antioxidant properties of vitamin C and help the body to break down and use the nutrient more efficiently.

There are many types of vitamin C formulations with bioflavonoids. Care/of Vitamin C is sourced from acerola cherries and is paired with bioflavonoids (quercetin, rutin, and hesperidin). Each of these on their own also have health-supportive characteristics.

  • Rutin has been found to support normal, healthy functions, body systems, processes, and organs, like neurological, respiratory, gastrointestinal, cellular energy, metabolic, reproductive, liver, and kidney wellness.
  • Quercetin supports antioxidants, cellular defenses, healthy immune system function, and responses to seasonal and environmental exposures.

Natural food sources of vitamin C, like citrus fruits, contain bioflavonoids, so the human body is used to receiving these beneficial nutrients together. By keeping them together in supplement form, it may enhance how the body can put the nutrients to use, although research has been inconclusive on showing this as a consistent effect. Still, bioflavonoids have benefits of their own, and can even be found as standalone supplements. When paired with vitamin C, it’s two-for-one nutritional support.

3. Ester-C (Calcium Ascorbate)

Calcium ascorbate is a form of vitamin C known as a mineral ascorbate, or buffered vitamin C. Because the nutrient is paired with calcium, it is considered to be less acidic in the digestive system, although human clinical research does not necessarily confirm this. Buffered forms of vitamin C are often used for people who feel gastrointestinal discomfort from ascorbic acid forms. This theory is based on animal research and has not been confirmed with human trials. Some also claim that by buffering vitamin C with minerals, it stays in the body longer, but studies do not support this conclusion either.

Ester-C also provides smaller amounts of calcium, typically around 100 mg per serving. The mineral is absorbed in the digestive tract along with the vitamin C, so this form can contribute to daily calcium needs.

4. Sodium Ascorbate

Sodium ascorbate is another form of buffered vitamin C that uses sodium instead of calcium. People who follow low sodium diets need to consider that the sodium in the supplement absorbs along with the vitamin C, so it should be factored into the daily sodium intake.

5. Ascorbic Acid

Ascorbic acid is used broadly to refer to vitamin C, since this is the form found naturally in fruits and vegetables. It can also be synthetic (made in a laboratory) and used in dietary supplements. Ascorbic acid is a widely used form of vitamin C. Research has found that both the natural and synthesized forms have the same absorption rate. Natural forms of vitamin C that include bioflavonoids, fiber, and other nutrients from whole foods may have an advantage over synthetic ascorbic acid on its own; however, there is a need for more well designed studies and standardized extracts to analyze any potential advantages and bioavailability of one form in comparison to the other.

6. Other Mineral Ascorbates (Potassium Ascorbate, Magnesium Ascorbate, Zinc Ascorbate, etc.)

Buffered vitamin C can be formulated with other minerals, including potassium, magnesium, zinc, and manganese. Less commonly, vitamin C may be buffered with chromium or molybdenum. Like calcium ascorbate, these sources of vitamin C also provide smaller amounts of the minerals that they are buffered with. Some types of buffered vitamin C supplements may include more than one mineral, such as calcium and magnesium.

When consuming minerals from supplements, it’s important to consider the total daily amount you’re getting. There are established tolerable upper intake levels (ULs) for most minerals. When you take a multivitamin, buffered vitamin C, and any other nutritional supplements, you could be getting minerals from many sources. Be aware of this and always ask your doctor before starting any supplements.

Read supplement labels carefully, but generally, the other buffered vitamin C supplements typically contain the following mineral amounts:

  • Potassium ascorbate: About 175 mg of potassium per serving (no UL has been set for healthy adults)
  • Magnesium ascorbate: About 75-100 mg of magnesium per serving (the UL is 350 mg for adults)
  • Zinc ascorbate: Between 10-40 mg of zinc per serving (the UL is 40 mg for adults)
  • Manganese ascorbate: Around 1 mg per serving (the UL for adults is 11 mg for adults)

Keep in mind that minerals can interact with other medications, so always make sure that your doctor knows about all of the supplements and OTC medicines you take, along with anything that you are prescribed.

7. Ascorbyl Palmitate

Ascorbyl palmitate is a fat-soluble esterized form of vitamin C. However, it is not the same as liposomal vitamin C. Ascorbyl palmitate has the same oral bioavailability of ascorbic acid on its own, since the ascorbic acid and palmitate are separated in the initial digestive process. However, when this form of vitamin C is used in multivitamins or other formulations with fat-soluble nutrients, the ascorbic acid likely helps to protect fat-soluble nutrients, which can be more likely to degrade from oxidative processes.

When it comes to topical vitamin C formulations, ascorbyl palmitate may be more bioavailable than other forms.

Vitamin C supplement types (pills, gummies and beyond)

Vitamin C supplements are available in many forms, including:

  • Capsules
  • Chewables
  • Liquids
  • Powders
  • Gummies

It’s all about choosing the delivery method that works best for you. If you struggle to swallow capsules, a chewable or gummy may be better. Some forms, like liposomal vitamin C, may only be available in certain types of products (like liquids or capsules).

Care/of vitamin C capsules are formulated for easy absorption.

What mode of vitamin C is best absorbed?

Vitamin C that comes from food has the most benefits. But overall, when comparing types of vitamin C supplements, the nutrient form matters more than the supplement type (capsule, gummy, chewable, etc.). Based on results from this study, liposomal vitamin C may have the highest ability to deliver vitamin C to the bloodstream. However, the form of vitamin C used was in tablet form and the doses were not disclosed. As a result additional well designed studies need to be done to understand which forms of vitamin C are most effective. According to other studies,many forms of vitamin C have similar absorption. When you pair vitamin C with bioflavonoids, you also maximize the support you get from the added components.

Quality of vitamin C

When you choose a vitamin C dietary supplement, you want to make sure that you are getting the best quality. There are several factors that you should keep in mind:

  • Third-party testing for purity and potency
  • Non-GMO
  • Free from ingredients of concern (vegan, gluten-free, etc.)
  • Form of the nutrient
  • Amount of the nutrient

Brand transparency is important. Care/of uses third-party testing not only to establish trust with you, but also to demonstrate that our formulations are manufactured with integrity (they contain what the label says they do).

Dosage of vitamin C

The Recommended Dietary Allowance (RDA) for vitamin C depends on a person’s age and stage of life.

  • Adults born female: 75 mg
  • Pregnancy: 85 mg
  • Adults born male: 90 mg
  • Lactation: 120 mg
  • Tobacco users: An additional 35 mg per day

In some cases, healthcare professionals may recommend greater than the RDA.

Can you take too much vitamin C?

The tolerable upper intake level (UL) for vitamin C is 2,000 mg for adults, but this does not mean that everyone can safely consume this amount. Higher dose intakes of nutrients should not be done without medical supervision.

Who would benefit from taking a vitamin C supplement?

Vitamin C is found in many foods, so while deficiency is not common, inadequate intake is more likely when specific factors are present, such as:

  • Decreased intake of fruits and vegetables
  • Gastrointestinal conditions
  • Restricted diets from food allergies or sensitivities
  • Tobacco use
  • Certain medications
  • Older age

There are other reasons why you may not be getting enough or why you may benefit from more vitamin C. Your healthcare provider can discuss the best way to support your nutritional needs.

Who would not benefit from a vitamin C supplement?

If you eat a diet that is rich in vitamin C foods, with several servings of fruits and vegetables each day, you may not need additional vitamin C. This may be true if you eat a diverse diet and also take a multivitamin that contains vitamin C. In this case, a vitamin C supplement is unlikely to cause harm, but may not produce additional benefits if you already consume a lot of vitamin C from foods.

When to take vitamin C

You can take vitamin C at any time of the day. If you already take other supplements, or take other medications, ask your doctor when it’s best to take your vitamin C.

Best way to take vitamin c for absorption

Vitamin C supplements usually absorb best when taken with a meal. Follow the instructions on your supplement and take as directed by your healthcare provider.

Possible side effects and contraindications

Vitamin C is considered to have low toxicity, but can still lead to gastrointestinal upset like nausea, diarrhea, and cramping. When consumed in higher amounts, it may lead to fatigue, lethargy, vomiting, or headaches, though this is more common from intravenous (IV) vitamin C than oral dietary supplements.People who have certain health conditions may need to avoid vitamin C supplements, especially at higher doses above the upper limit.

The Bottom Line

Vitamin C is an important nutrient for many aspects of wellness. From a healthy immune system to improving non-heme iron absorption, vitamin C is a vital antioxidant that the body can’t make. Vitamin C is found in many foods, and as a supplement, is available in many forms. Liposomal vitamin C and vitamin C with flavonoids are high-quality, well-absorbed supplements, but your medical provider can advise you on how much vitamin C you should take each day and the best form to meet your needs.

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