Vitamin C for Guinea Pigs

Here is an in-depth look at Vitamin C for guinea pigs.

If you are after a more specific in-depth look at a typical guinea pig diet, check out my “The Ultimate Guinea Pig Food List” article, I go pretty in-depth about all the foods and diet types your guinea pig could possibly want.

Secondly, if you are interested in finding out if your guinea pig is getting enough vitamin c in his or her diet, feel free to use my vitamin c calculator here.

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What is Vitamin C?

Vitamin C, or L-ascorbic acid, is a water-soluble nutrient. Most mammals and birds have an enzyme in their liver called L-gluconolactone oxidase which converts glucose into Vitamin C. Humans, guinea pigs, the Indian fruit bat, and a handful of other species are the only mammals who cannot make their own vitamin C because they lack this enzyme. Instead, they need to ingest it.

Vegetables and fruits contain Vitamin C in varying amounts. Plants make Vitamin C from glucose, as well, but they do it using a different enzyme and different biosynthetic pathways.

What does Vitamin C Do in the Body?

Vitamin C:

  • Reacts with oxidants that can damage cells, stopping them from creating damage in the cells
  • Helps form and maintain connective tissue, especially collagen. Collagen is the main structural protein component of connective tissue.
  • Converts lysine into L-carnitine. L-carnitine moves fatty acids around in the mitochondria when fats are broken down and helps generate metabolic energy.
  • Is required to synthesize the neurotransmitter norepinephrine.
  • Reduces the number of metal ions in the brain (e.g., iron, copper)
  • Causes Vitamin E to be regenerated
  • Improves the body’s ability to absorb iron.

What Does a Deficiency of Vitamin C Do to the Body?

A deficiency of Vitamin C causes:

  • Oxidative damage to lipids and proteins in the brain.
  • Scurvy (read more here), which is potentially fatal. In scurvy, vitamin C is kept by the brain for the neurons to function, and eventual death from the disease is likely due to a lack of vitamin C for the synthesis of collagen in the body’s cells. Collagen is an important structural component of blood vessels, tendons, ligaments, and bones.
  • Fatigue
  • Connective tissue weakness
  • Frail blood vessels
  • Teeth to Loosen or Fall Out

How Much Vitamin C Does a Guinea Pig Need?

A guinea pig should receive 10-30 mg/kg each day. Young, nursing or sick guinea pigs need higher levels, with a minimum of 30 mg/kg. Since Vitamin C is water-soluble, it does not get stored in the body. The body uses what it needs, and the excess is sent out of the body through the urine.

How Stable is Vitamin C?

Vitamin C does degrade and dissipate fairly quickly. The Vitamin C contained within guinea pig pellet food can degrade by about 50% in about six weeks’ time. Vitamin C is sensitive to light, heat, and oxygen, so you need to store it in a dark area away from heat sources. Also, try to keep it in a closed container. The Vitamin C in most fruit will degrade by about 20% in one month, but the Vitamin C in apples remains stable for 6-8 months (if the fruit lasts that long!).

What Fruits and Vegetables Provide High Levels of Vitamin C?

Here is a table of fruits and vegetables that contain Vitamin C, arranged from highest levels to lowest.

Milligrams per serving
Guava, 1 medium
Red Pepper, raw, 1/2 cup
Grapefruit, 1 pink or red
Orange, 1 medium
Kale, 1/2 cup
Green pepper, 1/2 cup
Brussel Sprouts, 1/2 cup
Strawberries, 1/2 cup
Broccoli, raw, 1/2 cup
Pineapple, 1/2 cup
Kiwi, 1 medium
Cantaloupe, 1/2 cup
Regular cabbage, 1/2 cup
Cauliflower, 1/2 cup
Red cabbage, 1/2 cup shredded
Tomato, 1 medium
Spinach, 1/2 cup
Plum, 1/2 cup sliced
Green Peas, 1/2 cup
Apricot, 1/2 cup sliced
Apple, 1/2 cup sliced
Grapes, 1/2 cup
Romaine Lettuce, 1/2 cup sliced

How Can You Tell if a Guinea Pig Has a Vitamin C Deficiency?

A guinea pig suffering from a deficiency of Vitamin C will usually exhibit these signs and symptoms:

  • Weakness, lethargy, or inactivity
  • Hair or coat becomes rough
  • Swollen joints can be making walking difficult
  • Loss of appetite or weight loss
  • Small spots of bleeding right underneath the skin
  • Internal bleeding due to weakened blood vessels
  • Wounds that don’t heal
  • Diarrhea
  • Discharge from the eyes or nose
  • Poor skin quality, which could result in pain when touching or handling him

How Long Does it Take for a Guinea Pig to Exhibit Signs of Vitamin C Deficiency?

If a guinea pig is prevented from eating Vitamin C, severe deficiency symptoms usually manifest in about two weeks’ time.

Should I Supplement Vitamin C?

If you feed your guinea pigs a healthy, well-rounded diet that includes Vitamin-C-enhanced guinea pig pellets along with plenty of fresh fruits and vegetables, your guinea pig is probably getting enough Vitamin C. However, Vitamin C is water-soluble. That means the body will use what it needs and then get rid of the excess by excreting it through the urine. So to be safe, it is a good idea to supplement your guinea pig’s diet with a Vitamin C supplement. If you are interested in finding the best supplement, check out my article here.

How Much is Too Much?

It is difficult to overdose on Vitamin C. I did some research online for what answers people are giving to the question, “Can guinea pigs overdose on vitamin C”, and I was amazed to find a lot of people saying “Yes, guinea pigs can overdose on Vitamin C”. The fact is that MASSIVE doses may cause some diarrhea. But guinea pigs tolerate high doses of Vitamin C very well. A study published in the scientific journal Toxicology and Pharmacology in 1997 detailed efforts to determine the ability of Vitamin C to protect guinea pigs from Aflatoxin toxicity (a toxin produced by a fungus). In this study, they administered 300 mg of Vitamin C per day to the test guinea pigs, and it did not harm them. The study showed that that amount of Vitamin C protected the guinea pigs from the toxic effects of the aflatoxin toxin.

In another study published in the journal Toxicology Letters in 1999, a group of guinea pigs was given 500 mg of Vitamin C to determine the ability of Vitamin C to protect from alcohol toxicity. The guinea pigs were not harmed by that level of Vitamin C, and the study showed that Vitamin C did decrease damage created by ethanol toxicity.

So the question is, “Can you overdose your guinea pig on Vitamin C?” I say no. If you really went overboard and administered some hugely massive dose (greater than 500 mg/day), then maybe you will create some ill effects. I’ve searched the literature extensively, and I have never found one case anywhere of an animal or a human dying from a Vitamin C overdose.

I am reminded of the book I read years ago by Norman Cousins called “Anatomy of an Illness”. He had a degenerative spinal condition, and his doctors said there was nothing they could do. So he did his own research and came up with his own treatment which included massive doses of Vitamin C injected directly into his bloodstream (25 grams). He recovered from his illness, even though until then, the doctors had said no one recovered from ankylosing spondylitis. Yes, Norman Cousins was not a guinea pig, and guinea pigs have different physiologies than humans. But the point is that Vitamin C is not toxic, even in large doses. Giving a 175-pound human 25 grams of Vitamin C is the equivalent of giving a 2-pound guinea pig 286 mg of Vitamin C. To learn more about the range of illnesses your guinea pig can contract, check out this article here.

What is the Best Way to Supplement Vitamin C?

You have several options when supplementing your guinea pig’s diet with Vitamin C. You can use liquid drops, you can use Vitamin C powder, or you can take some Vitamin C tablets and crush them up.

Ideally, you should NOT add Vitamin C to your guinea pig’s water, however. First of all, you don’t know how much he will be ingesting if you do it that way. Will he empty one full bottle of water each day? Oftentimes, the Vitamin C will change the taste of the water, and as a result, the guinea pig will intentionally drink less water because he doesn’t like the taste of it. Secondly, Vitamin C degrades rather quickly in water. How quickly? Well, that depends on your water. If your water contains metal ions, like copper or iron, the rate of degradation is increased markedly


Furthermore, a study published in Clinical Chemistry showed that when Vitamin C was dissolved in water inside glass and plastic containers, the glass and plastic both helped increase the rate at which Vitamin C degraded (it degraded in less than 24 hours). (Clinical Chemistry
August 2001 vol. 47 no. 8 1463-1464)

How fast Vitamin C degrades depends on pH, temperature, type of container, amount of light, and the amount of headspace in the container. Journal of Pharmaceutical Sciences Volume 53, Issue 10, pages 1248–1251

I could list more studies, but maybe that’s boring you. The point is, don’t put the Vitamin C in the water. It degrades within hours. Specifically, after 8 hours, only about 20% of the Vitamin C in the water is still active.

So what’s the best way to give Vitamin C to your guinea pig?

You could:

  • Put liquid Vitamin C drops directly into his mouth using a titrated dropper.
  • Give a Vitamin C treat. Oxbow makes a Natural Science Vitamin C tablet for guinea pigs that contains 25mg of Vitamin C and is said to be stable for two years, but once opened, must be used within 60 days.
  • Use powdered Vitamin C or crushed tablets and sprinkle it on a moistened green that he likes, like romaine lettuce.

Once again if you are after a more specific in-depth look at a typical guinea pig diet, check out my “The Ultimate Guinea Pig Food List” article, I go pretty in-depth about all the foods and diet types your guinea pig could possibly want.

And lastly, don’t forget to check out my vitamin c calculator here. I actually still occasionally use it if I am having trouble measuring my guinea pig’s intake.