15 doctors weighed in:

Are there negative side effects to taking large doses of slow release vitamin C to avoid colds?

15 doctors weighed in
Dr. Lawrence Rosen
Pediatrics
3 doctors agree

In brief: Yes but mild

Typically large doses of vitamin c are well tolerated as long as you're well hydrated - GI adverse effects like diarrhea or nausea can occur at very high doses.

In brief: Yes but mild

Typically large doses of vitamin c are well tolerated as long as you're well hydrated - GI adverse effects like diarrhea or nausea can occur at very high doses.
Dr. Lawrence Rosen
Dr. Lawrence Rosen
Thank
Dr. Raj Syal
Obstetrics & Gynecology
2 doctors agree

In brief: Yes

Mega doses of any vitamin is not recommended.
The benefits are not proven and marginal at best. A good multi vitamin should suffice.

In brief: Yes

Mega doses of any vitamin is not recommended.
The benefits are not proven and marginal at best. A good multi vitamin should suffice.
Dr. Raj Syal
Dr. Raj Syal
Thank
Dr. Vasu Brown
Anti-Aging Medicine
1 doctor agrees

In brief: Creates kidney stone

If the body pH is acidic you can test this by urine or saliva litmus test and this is not in the normal range between 6.
8-7.4 then you need to make sure before you take vitamin c your body is in alkaline range. Otherwise you can potentially create kidney stones and calcify other areas too. Vitamin c can be used upto 1000mg per day for colds and vitamin c flush high dose done for constipation.

In brief: Creates kidney stone

If the body pH is acidic you can test this by urine or saliva litmus test and this is not in the normal range between 6.
8-7.4 then you need to make sure before you take vitamin c your body is in alkaline range. Otherwise you can potentially create kidney stones and calcify other areas too. Vitamin c can be used upto 1000mg per day for colds and vitamin c flush high dose done for constipation.
Dr. Vasu Brown
Dr. Vasu Brown
Thank
Dr. Kathryn Mercer
Obstetrics & Gynecology
1 doctor agrees

In brief: No

There really isn't any huge harm in taking too much vitamin c as it is water soluble, and what you don't absorb will be excreted in your urine.
On the other hand, there isn't much evidence that it prevents disease.

In brief: No

There really isn't any huge harm in taking too much vitamin c as it is water soluble, and what you don't absorb will be excreted in your urine.
On the other hand, there isn't much evidence that it prevents disease.
Dr. Kathryn Mercer
Dr. Kathryn Mercer
Thank
1 comment
Dr. Nicole Bullock
A good multivitamin / prenatal vitamin will also help with your overall immune health. Vit D and DHA (=omega 3 = fish oil) are also good for the immune system. Don't forget the basics .... drink plenty of water, get good sleep, wash your hands and avoid contact with sick people!
Dr. Padmavati Garvey
Obstetrics & Gynecology
1 doctor agrees

In brief: Yes

There are negative side effects to taking too much of any vitamin.
It is debatable if vitamin c supplements even work in preventing colds. Our body needs minute amounts of vitamins. Taking more vitamins does not mean your body will work better. You are better off eating and orange and washing your hands frequently.

In brief: Yes

There are negative side effects to taking too much of any vitamin.
It is debatable if vitamin c supplements even work in preventing colds. Our body needs minute amounts of vitamins. Taking more vitamins does not mean your body will work better. You are better off eating and orange and washing your hands frequently.
Dr. Padmavati Garvey
Dr. Padmavati Garvey
Thank
1 comment
Dr. Philip Rosenblum
I absolutely agree with this answer. I have seen a large number of patient's taking 1000-2000 mg of vitamin C daily for years, complaining of heartburn and other gastro-intestinal complaints also for years. Stop the Vitamin C and many of these symptoms will recede. Most people fail to recognize side effect from their supplements, but worry tremendouly about them in a prescription medication.
Dr. Michael Rothman
Internal Medicine

In brief: Yes

Mega dose vitamin c can actually be dangerous.
It is true that vitamin c is water soluble & you will excrete any vitamin c that you don't use. However, in order to excrete vitamin c in your urine, you must also excrete minerals as well. Therefore, excess vitamin c can lead to mineral deficiencies, especially a copper deficiency. Be very cautious in megadosing any vitamin or mineral or amino acid.

In brief: Yes

Mega dose vitamin c can actually be dangerous.
It is true that vitamin c is water soluble & you will excrete any vitamin c that you don't use. However, in order to excrete vitamin c in your urine, you must also excrete minerals as well. Therefore, excess vitamin c can lead to mineral deficiencies, especially a copper deficiency. Be very cautious in megadosing any vitamin or mineral or amino acid.
Dr. Michael Rothman
Dr. Michael Rothman
Thank
Dr. Megan Bird
Obstetrics & Gynecology

In brief: Yes

Some women who take high dose vitamin c get diarrhea from it.
Otherwise it is pretty low risk.

In brief: Yes

Some women who take high dose vitamin c get diarrhea from it.
Otherwise it is pretty low risk.
Dr. Megan Bird
Dr. Megan Bird
Thank
Dr. Sheila Goodman
Obstetrics & Gynecology

In brief: No

High doses of vitamin c are unlikely to hurt anything since you'll just put any extra c into your urine.
On the other hand, high dose c has been shown to have no effect in preventing colds. The best way to avoid colds is frequent hand washing.

In brief: No

High doses of vitamin c are unlikely to hurt anything since you'll just put any extra c into your urine.
On the other hand, high dose c has been shown to have no effect in preventing colds. The best way to avoid colds is frequent hand washing.
Dr. Sheila Goodman
Dr. Sheila Goodman
Thank
Get help from a real doctor now
Dr. Keegan Duchicela
Board Certified,
11 years in practice
16M people helped
Continue
108,000 doctors available
Read more answers from doctors