Vitamin C is C-riously important for your immune health. And your immune system plays a big part in how your body reacts to the world. Immune cells can help you fight harmful germs. But those immune cells might accidentally fight your healthy cells if you experience allergies.

So, could there be a benefit to taking vitamin C for allergies? Here’s what the science says.

Does vitamin C work for allergies?

One small study with 71 participants showed positive results, but it’s not clear whether supplementing with vitamin C can help reduce allergy symptoms. Vitamin C does have lots of other well documented health benefits, though, so it’s worth a try!

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Vitamin C is a water-soluble nutrient. Unlike fat-soluble vitamins that tend to stick around longer in your cells, you need to make sure you’re getting enough vitamin C every day.

Even though vitamin C is found in a ton of foods like fruits and vegetables, it’s pretty common in Western populations for folks to have low blood levels of vitamin C. In fact, vitamin C deficiency is the fourth most common nutrient deficiency in the United States.

Having low vitamin C levels can negatively impact your bod in a number of ways, like weakening your immune system. But just because getting enough vitamin C is necessary for your overall health, it doesn’t mean that peeps with allergies necessarily need to supplement with extra vitamin C.

In fact, there’s not a lot of evidence that supplemental vitamin C benefits peeps with allergies who have adequate vitamin C intake.

Overall, the research behind using supplemental vitamin C for allergies is pretty limited. Plus, most of the available studies focus on intravenous (IV) vitamin C, not oral supplementation.

That’s an important callout because IV vitamin C is completely different from oral vitamin C supplements. This IV treatment usually contains much higher doses, and it’s typically given in a clinical setting.

High doses of vitamin C through an IV seem promising

The same small study above with 71 participants showed that high dose IV vitamin C helped reduce allergy symptoms like sleep issues, itching, and stuffy nose in adults with allergic respiratory disease or allergic skin disease.

Peeps were given an average of 7 to 26 doses of 7.6 grams (g) of vitamin C over a period of 3 or 12 weeks, depending on the type of allergy.

FYI: This is *way* more than the 250- to 1,000-milligram (mg) doses typically found in oral vitamin C supplements. Plus, IV treatment means it’s delivered directly into your bloodstream, so it has different effects than oral vitamin C.

Vitamin C may affect your histamine levels

A small 2013 study with 89 people found that when peeps with and without allergies were given high dose 7.5-gram injections of vitamin C, it led to a significant reduction in histamine. Histamine is a compound that plays a key role in the body’s inflammatory response.

Histamine’s released from cells in your immune system and causes allergy symptoms like itching and stuffy nose. So, theoretically, reducing the amount of histamine in your system may help reduce allergy symptoms.

Vitamin C may help folks with asthma

A small 2013 research review that included 3 studies (79 participants total) found that supplemental vitamin C in varying doses between 1 and 5 g may be effective for reducing asthma attacks and bronchial sensitivity in people with asthma.

Plus, a small, older 2005 study suggested that vitamin C supplements may help peeps with asthma decrease their dose of corticosteroid medication. But there’s no current research backing up these findings.

A 2014 research review showed that vitamin C supplementation may be helpful for reducing exercise-induced airway narrowing, which is common in people with asthma.


Although these findings are interesting, there’s not a lot of evidence to support the use of vitamin C supplements in treating any type of allergic condition.

That doesn’t mean vitamin C isn’t important for your immune or overall health. It definitely is. It’s just not yet clear whether supplemental vitamin C specifically benefits all peeps with allergies.

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Even though the jury is still out on whether or not peeps with allergies should be taking extra vitamin C in supplement form, it’s clear that vitamin C is important for health in general.

If your diet is deficient in vitamin C, your immune system could be compromised as a result. This could worsen allergic conditions as well as increase your susceptibility to infection.

Plus, vitamin C has powerful anti-inflammatory and antioxidant properties. Low vitamin C levels could contribute to increased inflammation and cellular damage, which could worsen allergy symptoms and negatively impact your overall health.

It’s always important to get enough vitamin C

If your diet is high in foods and beverages that are rich in vitamin C, then your vitamin C needs will most likely be covered. The problem is, many peeps don’t get enough vitamin C through their diets.

If your diet is low in vitamin C and you can’t make up for it with vitamin C-rich foods (like citrus fruits, peppers, and kiwi) and drinks (like orange juice and enriched bevvies) then it may be a smart idea to take a supplement.

Keep in mind that smoking cigarettes significantly increases your vitamin C needs by 35 mg per day. If you smoke regularly, you need to be aware of your vitamin C intake to keep up your levels.

If you’re interested in taking a vitamin C supplement, it’s a good idea to know how much you actually need.

Generally, adult men require 90 mg per day, while women need 75 mg per day. Pregnant and breastfeeding women require 85 and 120 mg per day, respectively.

A research review argued that most of us need between 100 and 200 mg per day to achieve optimal vitamin C levels in our cells and reduce disease risk.

Choosing the right vitamin C supplement

Most supplements provide between 250 and 1,000 mg of vitamin C per dose, which is typically more than you need daily. However, supplemental vitamin C, even when taken in high doses, is considered safe.

It’s generally recommended that adults not exceed 2,000 mg of vitamin C per day. (This includes vitamin C from food and supplements.)

When you’re searching for a vitamin C supplement, look for vitamin C in the form of ascorbic acid or liposomal vitamin C.

One study suggested that liposomal vitamin C, which is encased in tiny lipid spheres called liposomes, is a better pick than nonliposomal forms of vitamin C.

Is vitamin C safe?

Vitamin C is considered safe, even if you take it in high doses.

But it could lead to side effects like diarrhea, cramping, and nausea if you take excessively high doses (more than 3,000 mg). That’s simply because your bod can’t absorb all that vitamin C!

Where does the extra vitamin C go? It leaves your body through your urine. But for some folks that are more susceptible to certain types of kidney stones, high doses of vitamin C could increase their risk of developing kidney stones.

Peeps with certain medical conditions (like iron storage disorders) and folks undergoing chemotherapy or radiation treatment should check with their doctor before taking vitamin C supplements.

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There’s no doubt that having optimal vitamin C levels is super important for overall health. But it’s not clear if taking supplemental vitamin C is helpful for peeps with allergies.

It’s important to focus on overall diet quality, making sure you’re eating plenty of nutrient-dense foods rich in vitamin C like fruits and veggies.

If you have allergies and want to learn more about how diet and supplementation may help you, work with your doctor or a registered dietician.