Vitamin C (also known as ascorbic acid) can help reduce muscle soreness, fight off cold’s and increase libido. It is one of the most commonly taken supplements ever, it is nearly universally seen as the healthiest supplement to take, and many foods or drinks advertise the fact that they contain high levels of vitamin c.
There are many commonly believed benefits of vitamin c, some of which are still up for debate, and there are a great many benefits that are pretty much unheard of.
1Vitamin C can protect agains the common cold. One of the most commonly held beliefs is that vitamin c is an effective weapon against catching the common cold. The evidence appears to find that taking vitamin c will not help protect against a common cold unless you are stressed – in which case there does seem to be a case for taking vitamin c to protect yourself (1).
So if you are a regular person, with normal amounts of stress, then taking high levels of vitamin c will not prevent you from getting a cold. However, some studies do indicate that taking vitamin c can help to reduce the length of time that you spend suffering with a common cold (2).
2Vitamin C can boost energy. Vitamin C is often used to help cancer patients to improve their quality of life and to reduce fatigue, but the evidence for this is mixed (3).
A Study on 141 healthy volunteers (office workers) in Nutrition Journal (2012) found that intravenous vitamin c (10g) led to a significant drop in reported fatigue for the entire day after taking it (4).
In a 2013 study by Huck, Johnston, Beezhold, & Swan twenty adults were split into two groups, one received a placebo while the other received 500mg of vitamin c for a period of 4 weeks (5).
This study was performed on volunteers who were clinically obese and also used exercise. While weight loss and fat oxidation were unaffected, fatigue was reduced in the vitamin c group.
After looking at the evidence, it appears that vitamin c could potentially be an effective method for reducing fatigue, but the doses seem to be quite high. 10g of vitamin c per day is a very high dose indeed.
3Vitamin C intake can increase endurance. Your rate of perceived exertion is a measure of how difficult you find an exercise based on a scale (usually 1-10 with 1 representing little to no effort and ten representing maximum effort). For example, a professional marathon runner and a first time jogger would have very different RPE’s while walking 200m at a similar pace.
In the same study we looked at earlier (Huck, Johnson, Beezhold, & Swan 2013) the participants’ RPE scores were improved through the supplementation of 500mg vitamin c. Interestingly, a study in the Journal of Applied Physiology (1983) found that giving ultra marathon competitors 1,500mg of vitamin c had no effect on their RPE score (6).
However, there were many differences between these two studies. Firstly, anyone running an ultra marathon is going to be in peak physical fitness – so vitamin c may be effective, but not in highly trained individuals. Secondly, the dosages were completely different in the two studies 500mg in the 2013 study on obese volunteers, and 1,500mg in the ultra marathon runners study.
4Vitamin C can decrease oxidation (works as an anti-oxidant). Many supplements are sold for their antioxidative properties, and vitamin c is one of them. A 2011 study in the Pakistan Journal of Biological Sciences by Mazloom et alfound that vitamin c supplementation “can decrease fasting and postprandial oxidative stress and may prevent diabetes complication” (7).
A study in Free Radical Biology & Medicine (2011) found that 2 doses of 500mg vitamin c led to a reduction in systemic oxidation compared to a placebo (8).
Other studies have failed to find any significant link between vitamin c supplementation and reduced oxidation.
A study in Pharmacological Reports (2010) by Lagowska-Lenard, Stelmasiak, & Bartosik-Psujek found that “although administration of vitamin c (500mg/day, iv) to ischemic stroke patients since the first day ischemic stroke resulted in elevated serum levels of antioxidants, it did not substantially improve the clinical and functional status of patients after 3 months” (9).
In other words, vitamin c produced an anti-oxidant effect but created no noticeable change.
Another study, this time in the European Journal of Clinical Nutrition (2004) found that taking vitamin c orally did not lead to any changes and did not lead to an anti-oxidant effect (10).
Finally, we have a 2008 study from the Annals of Nutrition & Metabolism which found that “administration of 1,000mg of ascorbic acid plus 400 IU of alpha-tocoherol for 6 months is not useful for diminishing oxidative stress and DNA damage in healthy elderly adults.” (11).
Essentially, as with the other “benefits” there is an equal amount of evidence both for and against the effectiveness of vitamin c at decreasing oxidation.
5Vitamin C may increase sexual activity (but not masturbation). A study in 2002 was published by Brody in Biological Psychiatry (12).
In the study, 81 subjects were either administered a placebo (39 participants) or 3,000mg of vitamin c per day (42 participants).
The subjects were asked to record their sexual activity and masturbation during a 14 day period. The study found that those who took vitamin c had significantly more sexual activity (intercourse) but did not masturbate more. This was more prominent in couples who did not live together, and in women, the study also saw an improvement in mood in those who took vitamin c.
There is definitely a need for more study into this, as at the moment there is only really this one study. If it can be repeated and the same results recorded then this could be a very interesting benefit.
6Vitamin c may help improve well being and reduce depression. Some studies appear to indicate a mood enhancing effect of vitamin c particularly in the elderly. A 2011 study by Zhang, Robitaille, Eintracht, & Hoffer looked at hospitalised patients (a population that commonly suffers from vitamin c deficiency) (13).
The study was a double blind procedure that split the participants into those who received vitamin c and those who received vitamin d.
The study found that patients who were given vitamin c saw improved mood (a 34% reduction in mood disturbance). A similar study in the Journal of Nutritional Neuroscience (2016) looked at 205 volunteers split into two groups, a vitamin c group and a control (placebo) group (14).
The vitamin c group also took 12mg per day of Beta-carotene and 400mg per day of vitamin e so this study isn’t perfect as a test for vitamin c, but both beta-carotene and vitamin e are also anti oxidants so the results are still relevant.
The study found that after 12 months increased vitamin c levels were associated with “more positive mood, greater improvements in global assessments of intellectual functioning and a reduction in everyday errors of memory, attention and action”. So not only does vitamin c appear to improve well being and mood, it also seems to improve cognitive function.
Not all studies found vitamin c to improve mood though, a study in The American Journal of Clinical Nutrition (1981) looked at the effects of vitamin c on 94 elderly inpatients of a hospital (15).
After 2 months the researchers had found no changes in mood or mobility in the group taking vitamin c.
After looking at the evidence, it seems that there may be a small improvement in mood, particularly if people are already suffering from low baseline scores for mood. You may also see results if you have been deficient in vitamin c, but this isn’t guaranteed.
7Vitamin C may help to reduce heart rate and increases blood flow. Lots of studies have demonstrated the effectiveness of vitamin c in improving blood flow in populations that have impaired blood flow (smokers, the obese).
A 2011 study by Fernandes et al found that 500mg of vitamin c helped to improve blood pressure in obese children who were suffering from mental stress (16).
A study in the European Journal of Internal Medicine found that vitamin c was able to improve blood flow, most likely due to it being an effective anti oxidant (17).
A similar study in 2011 by Stewart, Ocon, & Medow looked at people who were suffering with tachycardia syndrome (18).
They found that supplementing with vitamin c led to improvements in blood flow, they also concluded that this was due to the anti oxidant properties of vitamin c.
One of the more interesting studies out there, looked at smokers. A population group that are often at risk of poor blood flow due to the effects of smoking. The study was published in the International Journal of Vitamin & Nutrition Research (2003) and it found that taking 2g of vitamin c before smoking led to a reduction in the negative effect of smoking on blood flow (19).
8Vitamin C may protect your bone density as you age. A 2009 study in Osteoporosis International by Chuin et al looked into the effects of vitamin c on bone mineral density (20).
The study involved 34 post menopausal women (a population that is often affected by Osteoporosis), and split them into 4 randomised groups: Placebo, Antioxidant, Exercise & Placebo, Exercise & Antioxidant.
After 6 months they looked at the results, vitamin c supplementation was found to be as effective as exercise at preventing loss of bone mineral density. Considering exercise is one of the most commonly prescribed methods to prevent osteoporosis, this is quite a big deal. Interestingly, the study found that combining exercise and vitamin c did not lead to any additional benefits.
A similar study in The Journal of Nutrition, Health & Aging (2010) found that 1,000mg of vitamin c combined with vitamin e could help to prevent age-related osteoporosis (21).
9Vitamin C may help to reduce muscle damage and muscle soreness.While muscle damage is in some ways necessary for the building and repair of muscle tissue, too much muscle damage (particularly that experienced by brand new lifters) can prevent you from training (22).
A study in the Journal of Sports Medicine & Physical Fitness (2008) found that taking 1000mg of vitamin c prevented muscle damage in untrained males who participated in 30 minutes of intense exercise (23).
A similar study in the International Journal of Sport Nutrition & Exercise Metabolism (2006) also found that vitamin c (3000mg per day) helped to reduce muscle soreness after eccentric exercise (24).
A study in 1992 explored the effect of vitamin c supplementation on delayed onset muscle soreness (known by many gym goers and sports people as DOMS), it found that there was a significant reduction in soreness in the vitamin c group compared to the placebo group (25).
Unfortunately the study size was very small (19 participants) and the researchers decided that the exercises used may have been too intense, but it’s still an interesting find none the less. But not all studies have found a link between vitamin c intake and muscle soreness reduction. A 2006 study in the Journal of Sports Medicine & Physical Fitness found that taking 3 loads of 1,000mg vitamin c per day for eight days had no effect on delayed onset muscle soreness (26).
Another study in 2004 in the European Journal of Applied Physiology looked at the effect of vitamin c intake on recovery from eccentric exercise (27).
The study found no evidence that vitamin c had any effect on exercise recovery. Similar results were found (or not found, as it were) in a 2011 study by Theodorou et al in the American Journal of Clinical Nutrition (28).
The study lasted 11 weeks, and was a double blind study. There were 28 participants split into a placebo group and a group who supplemented with vitamin C and vitamin E. No significant differences were seen between either group.
There is even a study that found that vitamin c hindered the recovery of muscle function. The study, in the British Journal of Nutrition (2006) found that vitamin C reduces reactive oxygen species (ROS) but had no effect on DOMS (29).
It also found that “ascorbic acid supplementation may inhibit the recovery of muscle function”.
After reviewing the evidence, it’s difficult to come to a conclusion. While some studies have found an improvement in recovery, a reduction in muscle damage and muscle soreness, other studies have failed to find anything, or have found the reverse. Worth trying, if you’ve just started training again, and you’re suffering from DOMS.
Vitamin c is perfectly safe to consume when taken within your recommended daily allowance. That being said, there can be a few smal side effects.
1Vitamin C can cause diarrhea in large doses. Take too much and you can experience side effects such as gastrointestinal distress or diarrhea (30).
Doses of 2,000-6,000mg can lead to diarrhea (31).
2Vitamin C may also lead to dental erosion if you are taking your vitamin c in tablet form (32).
3Vitmain C can lead to kidney toxicity in very rare cases. While not common, if you are consuming very high levels of vitamin c (7,000+mg per day) you could potentially cause kidney toxicity (known as Oxalate Nephrotoxicity). A 2008 case study describes an elderly man who died from renal failure after taking massive doses of vitamin c (33).
According to examine.com, the recommended dosage for vitamin c is around 100-200mg per day (34).
However, if you are an athlete and training at a high intensity you could potentially prevent a cold by taking 2,000mg per day. Anything above that could cause some of the side effects mentioned above. Remember to include all dietary sources of vitamin c when calculating your total.
What are the signs of vitamin C deficiency? Signs of vitamin deficiency include dry and splitting hair; gingivitis (inflammation of the gums) and bleeding gums; rough, dry, scaly skin; decreased wound-healing rate, easy bruising; nosebleeds; and a decreased ability to ward off infection.
Can you overdose on vitamin C? Vitamin C is water soluble, which means that if you take more than your body can use, the excess is usually excreted without causing harm. However you can get diarrhea and cramps from overdosing.
Can you get kidney stones from taking too much Vitamin C? It has been found that too much vitamin C can double your risk of getting kidney stones. However there is no guarantee that you will develop them.
What are the side effects of vitamin C? Side effects may include skin flushing, headache, nausea, diarrhea and an upset stomach.
How much vitamin C should you take when you’re sick? Ingest the same amount as you would normally take. More than 2000 mg is not recommended.
Is ascorbic acid and vitamin C the same? Yes.
What is scurvy? Scurvy, is a severe form of vitamin C deficiency.
Can vitamin C help the immune system? It may not be the cure for the common cold but vitamin C may protect against immune system deficiencies making you more able to resist colds and the flu.
Vitamin C is a fantastic supplement, that may provide many benefits. As with all vitamins and minerals though, there are more benefits to consuming it naturally through your diet than in pill form. Most of the benefits mentioned in this review, were only seen in people who were deficient in vitamin c already. If you are already consuming enough through your diet, then supplementing with vitamin c will provide little benefit.
In fact there is even a risk that combining a vitamin c supplement with a diet that is already high in vitamin c could lead to some nasty side effects. As to the effect of vitamin c on colds, this is still up for debate. Anecdotal evidence rarely counts for much, but many people say that taking vitamin c supplements or drinking orange juice makes them feel better when suffering from a cold.
Whether this is the placebo effect at work or not is hard to say, but there does seem to be some evidence that vitamin c can shorten the time spent suffering from a common cold, even if it doesn’t actually prevent colds in the first place.