Can You Overdose On Vitamin C?

Written by Angie Arriesgado
can you overdose on vitamin c

As a water-soluble nutrient, vitamin C is not stored in the body. Any excess is simply flushed out, meaning that vitamin C overdose isn’t really a concern for many people. But it can happen on rare occasions. In this blog post, we’ll go over some of the signs you need to watch out for and how to avoid overdosing in the first place.

Is it even possible to overdose on vitamin C?

Yes, overdosing is quite possible but highly unlikely for healthy individuals. You see, vitamin C has low toxicity, even at very high doses. Even if you’re eating a ton of vitamin C-rich foods or taking a couple of capsules more than the recommended serving size of our Intelligent Labs Liposomal Vitamin C supplement, you will generally be fine. Again, the body will readily flush out any excess vitamin C.

How to prevent a vitamin C overdose?

The best way to prevent a vitamin C overdose is by sticking to the recommended daily intake (RDI):

0-6 mos40mg40mg
7-12 mos50mg50mg
1-3 yrs15mg15mg
4-8 yrs25mg25mg
9-13 yrs45mg45mg
14-18 yrs75mg65mg80mg115mg
19+ yrs90mg75mg85mg120mg

As you can see, you don’t need to take huge amounts of vitamin C to get your daily fix! 90mg to 120mg for adults 19+ is quite a low dose.

Just take note though that smokers need to add 35mg/day to the RDI values indicated above. This is because smoking can speed up the oxidation process since their bodies use it up at a faster rate.

And here are the tolerable upper intake levels (UL) for vitamin C:

  • 1-3 yrs – 400mg
  • 4-8 yrs – 650mg
  • 9-13 yrs – 1200mg
  • 14-18 yrs – 1800mg
  • 19+ yrs – 2000mg

If you need to go beyond the UL, please make sure it’s under medical supervision, especially if you’re also taking medication or undergoing treatment for some condition.

How much vitamin C can you take before you overdose?

No specific dosage has been identified as being in “overdose territory”. But it’s been reported that healthy individuals will tolerate a daily dose of up to 4g. The Linus Pauling Institute even claims that doses of up to 10g/day aren’t toxic or harmful to health.

For safety reasons, however, we suggest consulting with your doctor if you plan to take more than the tolerable upper limit (2g/day) for an extended period.  

What are the side effects of taking too much vitamin C?

Taking more than the official tolerable upper intake levels of 2000mg/day is not recommended. If you do, then you may experience acid reflux, nausea, flatulence, bloating, diarrhea, and general abdominal discomfort. Nothing too serious, right? Fortunately, that’s correct. Most of the side effects of excessive vitamin C intake are relatively minor.

However, diabetics beware! Excessive doses of vitamin C can mask low blood glucose readings, that is, it can lead to inaccurate readings of blood glucose levels. This can be scary for diabetics because they may not understand why they’re experiencing the classic symptoms of low blood pressure (shaking, sweating) when their glucose monitor says otherwise. They may opt not to take medication and eventually pass out or even have a seizure!

Another possible side effect of vitamin C overdose is kidney stones. One woman taking 4g of vitamin C daily for several months developed kidney stones. While there are no large-scale studies for this possible vitamin C overdose effect, it’s better not to go beyond the upper 2g limit if you have a kidney condition.

Additionally, individuals who need to limit their iron intake, such as those with hemochromatosis, should stay within the recommended intake. This is because vitamin C can enhance the absorption of plant-based iron, and high doses of vitamin C may lead to excess iron absorption!  

How to treat a vitamin C overdose?

If you notice any of the symptoms listed above, the best thing to do is to cut your vitamin C dosage immediately. Drinking more water may also help to flush out the excess dose faster. Please speak with your doctor if symptoms don’t clear after a short while. 

Can vitamin C be toxic?

Vitamin C is generally known for being acidic, but not toxic. Getting vitamin C toxicity from food isn’t likely. However, taking it from supplements or intravenous injections, where it’s much easier to take high doses, may lead to side effects.

liposomal vitamin c bottle with orange

Who needs to take high doses of vitamin C?

Healthy individuals typically do not need to take high doses of ascorbic acid. But those who are sick and need an immunity booster may benefit from high doses. Vitamin C is also said to help shorten the duration of common colds, which is great for busy individuals who cannot afford to be sick for several days!

Moreover, while this may be quite controversial, cancer patients may also benefit from vitamin C megadoses. Alternative medicine practitioners are certainly huge fans of this approach. More recent studies show that taking megadoses of vitamin C in addition to other cancer treatment options (chemotherapy, radiation therapy, etc.) may be beneficial. But more research needs to be done to confirm these initial findings.

Additionally, high doses of intravenous vitamin C may also help major trauma and burns patients. These patients have increased free radical production in their bodies. Since vitamin C is also a powerful antioxidant, high doses may help with pain management and treatment.  

Is there a form of vitamin C that can prevent an overdose?

Unfortunately, there is none. It all boils down to individual intake. Getting a vitamin C overdose from food is highly unlikely. But it’s easier to abuse intake via supplements or intravenous injections.  

That said, following the recommended daily intake when taking ascorbic acid supplements has an advantage. About 70-90% of ascorbic acid is readily absorbed when taken in doses below 180mg/day. The higher amount you take, however, the lower the absorption rate. So, in the case of vitamin C ascorbic acid supplements, less is definitely more.

If you need to take upwards of 500mg/day and be assured of optimal absorption rates, then a liposomal vitamin C supplement would be a superior choice. The liposomes are made of a phospholipid bilayer which mimics the substance found naturally in all of our cells. The vitamin C molecules are inserted inside these liposomes. So, when the cells absorb the liposomes, they unknowingly absorb the vitamin C molecules within, too!

Check out this blog post which discusses the similarities and key differences between regular vitamin C, ascorbic acid, and liposomal vitamin C formulations.


A vitamin C overdose may not be fatal, but side effects can be uncomfortable. This is why our Intelligent Labs Liposomal Vitamin C supplement’s recommended serving size is only 2 capsules (1000mg/day). It’s still well within the tolerable upper limit, so you can enjoy vitamin C’s health benefits without worrying about overdosing! Lastly, check out this blog post on when to take our Liposomal Vitamin C.