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Vitamin C, Mega-Dose Products


Supplements Descriptions

by Gary F. Zeolla

This article will review five different products. But first, some general comments on what would be an optimal intake of vitamin C.

Optimal Vitamin C Intake

The Daily Value (DV) for vitamin C is 60 mg, while the RDA for adult men is 90 mg. But many believe these levels should be higher. Some even believe they should be a lot higher, along the lines of several grams a day. However, such levels would be impossible to attain from foods.

In my article Folly of Mega-Dose Supplements, I state:

My point is this, God would not have created our bodies in such a way so as to require levels of nutrients that are impossible for us to attain from the foods that He created for us to eat. For those who do not believe in God, the argument still holds. The human body would not have evolved to require levels of nutrients that were impossible to attain from the foods human beings were eating throughout their evolution.

In-between these two levels would be the following, "Some studies suggest that adults should take between 250 mg and 500 mg twice a day for maximum benefit" (University of Maryland Medical Center).

500-1000 mg a day is a level that might be able to be attained from diet, but that would require eating a LOT of fruits and vegetables and concentrating on only eating ones that are rich in vitamin C. But even 500-1000 mg would be a mega dose of vitamin C, supplying 833 - 1,666% of the DV. As such, such levels carry potential risks:

When a high intake of vitamin C is discontinued suddenly, the body may perceive this as a deficiency. It is a type of withdrawal effect, and could be particularly serious in a newborn whose mother took large amounts during pregnancy (Parsonnet, Mia. M.D. What’s in Our Food? Madison books: New York, 1996., p.46).

However, one of the possible benefits of such amounts is, "Treating allergy-related conditions, such as asthma, eczema, and hay fever (called allergic rhinitis)" (University of Maryland Medical Center). I have a serious problem with allergies, so that is why I fell for such hype and experimented with different vitamin C supplements containing mega-doses of vitamin C.

Twinlab's C 500 Caps

This was the first vitamin C supplement I tried. It is a basic vitamin C supplementing, containing 500 mg of vitamin C in the form of ascorbic acid, and with no other active ingredients. There are many such vitamin C widely available. But I went with this one for the following reasons:

First, it is very inexpensive. Second, the vitamin C is crystalline vitamin C, which is a pure form of vitamin C. Third, there are few additional ingredients (just cellulose, gelatin, purified water, and MCT [medium chain triglycerides, a kind of fat]). Fourth, there are no artificial ingredients.

For a while, it seemed like this supplement was benefiting me. Specifically, the basic allergic reactions like a runny nose, sneezing, and itchy eyes seemed to be less pronounced when I took this product. But it didn't help with other problems I get when I am exposed to something I am allergic to, namely, nasal congestion, a feeling of bugs crawling over me, and worse of all, not being able to sleep at night. But still, there was some benefit. I even tried starting and stopping it a few times, and when I did, the a runny nose, sneezing, and itchy eyes would increase, but then lessened as soon as I started to take it.

However, after taking it for a while, I ended up with problems, mainly, I ended up urinating frequently, including waking up at night to do so. It simply was not worth losing sleep over, so I had to stop using this product. It's possible that my tissues were already saturated, so any more intake was simply being excreted.

However, if you are still intent on taking a basic vitamin C supplement, then Twinlab's C 500 Caps is better than most. It is available from iHerb and Amazon. For iHerb, use coupon code HOP815 to get $5.00 off your first order. But as for me, I stupidly experimented with other products.

Natrol's Ester C with Bioflavonoids

Each capsule of Natrol's Ester C with Bioflavonoids contains 500 mg of vitamin C in the form of calcium ascorbate, along with 200 mg of citrus bioflavonoids. It also contains 50 mg of calcium from the calcium ascorbate.

Most vitamin C supplements use ascorbic acid. But, as the name implies, this form is acidic. Some find that this upsets their stomach. But the calcium in the Ester C "buffers" the ascorbate and thus might lessen any stomach upset. It is also claimed that calcium ascorbate is better absorbed than ascorbic acid, but there is little evidence to support this claim.

However, this Natrol's Ester C has citrus bioflavonoids added to it. This is how vitamin C is found in nature, in "complex" with bioflavonoids. Bioflavonoids are said to be antioxidants in their own right and help to increase the absorption of vitamin C. As the name implies, such bioflavonoids are found in citrus fruits like oranges. They are especially concentrated in the "white" portion on the inside of the rind. It is for this reason that it is recommended when peeling an orange that you leave as much of the white part on as possible.

Given all of this, the idea of combining bioflavonoids with vitamin C seemed to make sense, and that is why I tried this product. However, after as short while, it made me drowsy. Initially, this helped me to sleep at night. But then, I began feeling drowsy during the day, even if I only took it at bedtime. And then even worse, I began having episodes of dizziness, so I had to stop taking the product.

I assumed at the time that the problem was due to the vitamin C being in the form of calcium ascorbate. This was different from the the ascorbic acid in the C 500 Caps, which did not cause this problem. But whatever the case, I was not able to take this product long enough to know if it was more beneficial than regular vitamin C or not, but on thing is sure, it is more expensive. But if you want to try it, it is available from iHerb and Amazon. But it is now called Natrol, Easy-C.

Twinlab's C Plus Citrus Bioflavonoids

I assumed the drowsiness and vertigo problems with the Natrol Ester C were due to the vitamin C being in the form of calcium ascorbate. But later, I tried Twinlab's C Plus Citrus Bioflavonoids. It also contains 500 mg of vitamin, along with 325 mg of bioflavonoids. However, the vitamin C is in the form of ascorbic acid. But after a few days, I again experienced the vertigo. Needless to say, I stopped the product. What this meant was it was the bioflavonoids that was causing the problem.

And I am not alone. According to, dizziness is one common side effect of bioflavonoids. But there are many others. And note, this comes from a website about drugs. That is because bioflavanoids were thought to have an anti-cancer effect and thus were included in such drugs. However, newer research shows they might actually cause cancer and could harm a developing pre-born baby if taken by a pregnant woman. The reason for these problems is the amount of bioflavonoids found in drugs or supplements is much greater than could be attained from food. You would have to eat about 50 pounds of lettuce to attain the amount of bioflavonoids found in the previous product and about 80 pounds for the amount in this product (The Scientist).

As such, it is no surprise I had problems with both of these products, and I do not recommend them. But if despite these very real potential dangers, you are intent on trying this product, it is available from iHerb and Amazon.

Twinlab's "Ultra Harvest" Premium Natural C

Another product I tried was Twinlab's Premium Natural C, a part of its "Ultra Harvest" line of products. Each tablet contains the following:

Vitamin C (from nutritional yeast) - 250mg - 417% DV
Iodine (from nutritional yeast) - 23mcg - 15% DV
Citrus Bioflavonoid (from nutritional yeast) - 100mg
Green Algae - 25mg
Herb Blend - 100mg

Quoting Twinlab's description, "Twinlab's Ultra Harvest supplements are premium formulas that offer all natural, high quality nutrients derived from whole-food sources to provide you with the most effective formulas for achieving optimal health and wellness." That means the difference between this product and the above products is the nutrients are food based not synthetic.

With it being food derived, I hoped it would not cause the same problems as synthetic vitamin C with bioflavonoids. This product is considerably more expensive than any of the above three products. But given my severe allergy problem and the problems I had with the above three products, I figured it was worth a try. I took one tablet for two days, and the second night, I couldn't sleep a wink. That is what happens to me when I consume something I am allergic to.

My guess at the time was the problem was not caused by the vitamin C or bioflavonoids but by the "herb blend." This is a mixture of nine different herbs. I normally shy away from products with such a mixture or items as inevitably I am allergic to one or more of them. But I really wanted to try a food-based vitamin C supplement, and this was the only one I could find at the time.

Needless to say, I stopped taking the product. And I have since realized that paying the extra money for "food based" supplements is not worth it. Such supplements are no better absorbed or utilized than so-called synthetic nutrients. And I must not be the only one, as this product and Twinlab's entire "Ultra Harvest" are no longer available.

Nature's Way Alive Organic Vitamin C
(100% Whole Food Complex)

It wasn't until after my problem with the above product that I came across this one. Like the above product, the vitamin C in Nature's Way's Alive Vitamin C is food based. But unlike the Twinlab product, this Nature's Way product only contains vitamin C, but with all of the naturally occurring bioflavonoids and other co-factors. Moreover, rather than yeast, the vitamin C is derived from four different fruits (Acerola, Goji, Amla, and Kiwi), and as an added plus, they are all organic.

This Alive Vitamin C is available in two forms, capsules and a powder. The latter is cheaper, but I went with the former. I used to believe it is best to spread out one's intake of supplements if possible. With the capsules, it is easy to do so. Each capsule contains 125 mg of vitamin C, so I could easily take one capsule with each of up to four different meals. The powder contains 500 grams/ teaspoon, so it would be hard to measure out a smaller dose, and even harder to split it up over two to four doses.

It should also noted that the reason it takes four capsules of the Alive Vitamin C to attain 500 mg versus just one capsule for the first three items above is due to the "whole food" aspects of the Alive Vitamin C. The product contains not just the vitamin C but also significant amount of the bioflavonoids and co-factors found in the original fruits.

However, the downside to this product is it is the most expensive of all of the products described on this page. But given my allergy problem, I decided it was worth a try. I decided to take three capsules a day, one with each major meal.

I took it for several days, but I ended up with the same problem as with the Twinlab product; I had problems sleeping at night. I've never eaten the first three fruits used to derive the vitamin C from, but maybe I was allergic to one or more of them. But whatever the case, I stopped taking it. And that ended my experimentation with mega-doses of vitamin C.

Nature's Way's Alive Organic Vitamin C is available from iHerb and Amazon. When ordering from the former, use code HOP815 to receive $5.00 off your first order.


I had a problem with every mega-dose vitamin C product I tried. This could have been due to being allergic to one or more of the ingredients. Or more likely, it is because taking mega-doses of vitamin C causes a negative reaction in my body. Given that I get about 250 mg in my diet, and another 90 mg from my multi, that is probably more than enough, so any more is simply unnecessary and problematic. In fact, the basic allergic reactions like a runny nose, sneezing, and itchy eyes have not been problematic for some time, even when I am not taking a specific vitamin C supplement, so I am already getting what I need. Unfortunately, I still have other allergy problems, like not sleeping at night, but mega-doses of vitamin C are not in any way helping with that, but making things worse.

This all confirms what I wrote in my book God-given Foods Eating Plan, "God did not intend for us to get our nourishment from pills. He put all that we need in the foods He provided for us. But we need to eat a variety of these God-given foods" (p.15). As such, it would make no sense for there to be benefit from mega-dose supplements.

But if you want to to experiment with different doses of vitamin C, such are available from iHerb and Amazon. For iHerb, don't forget to use coupon code HOP815 to get $5.00 off your first order. But if you do, I would recommend avoiding products with bioflavonoids and the unnecessary expensive of "food based" vitamin C, and just stick with basic products like the Twinlab's C 500 Caps. At least that way, you won't waste unnecessary money and will lessen the chances of adverse reactions. That is why that product is the only on this page with a rating hither than one star.

Vitamin C, Mega-Dose Products - Supplement Descriptions. Copyright 2008, 2017 by Gary F. Zeolla.

The above article was posted on this site June 1, 2008.
It was updated June 21, 2017.

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