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Resveratrol A to Z

Resveratrol (res-ver-a-trol)

Resveratrol is a type of polyphenol that can be found naturally in a variety of sources including grapes, Japanese knotweed (giant knotweed), berries, peanuts, dark chocolate and tea.

The French Paradox: Resveratrol, a compound found in red wine, first gained publicity in the early nineties when the CBS television show, 60-Minutes, investigated why people living in France, despite eating diets high in saturated fats, had lower rates of coronary heart disease than people living in the United States. The report concluded that a higher consumption of red wine may play a role in lowering coronary heart disease. Since then, researches have pointed to resveratrol, a substance contained in grape skins (and other plants such as Japanese knotweed), as the compound with the possibility of preventing or delaying coronary heart disease and many other health conditions. 

What Should You Know Before Purchasing Resveratrol?

Its not surprising that consumers are confused about resveratrol products. Resveratrol is a general name for a product that is available in various purities: 5%, 10%, 20%, 50%, and 99%.  In principle buying resveratrol is the same as buing gold. Gold is available in different purities and the law requires the dealer to clearly stamp the purity of the gold on the item (e.g. 5 , 9, 14  or 24 karat). If the resveratrol manufacturer does not indicate the purity on the label, then there is no way of knowing the amount of trans-resveratrol in the product, or if it has any health benefits at all. Resveratrol can provide great health benefits ONLY if it contains sufficient amounts of trans-resveratrol, the active ingredient and the beneficial substance in resveratrol.  “resveratrol” does not mean Trans-resveratrol.

It is important to note that most resveratrol sold in USA and abroad is of a low purity (50% or less ).  Since the FDA does not regulate the purity content labeling of dietary supplements, it is not surprising that manufacturers that offer low-purity resveratrol are doing it solely for monetary gain and therefore they do not disclose the purity content of the product. Instead, they use misleading descriptions such as “Extra Strength”, “Super Potency”, “High Purity”, “Pure Resveratrol” and other misleading statements. Remember, If the label does not clearly indicate the amount of trans-resveratrol, then there is no way of knowing its purity content, or if it even has any health benefits. It is important to note that 250-500 mg of trans-resveratrol is the minimum daily amount that is needed to promote the benefits of this product for healthy individuals, (higher dosage may be required for individuals with certain health conditions).

What is “Pure” Resveratrol?

“Pure Resveratrol” refers to a product that should contain contains only TRANS-RESVERATROL, the active ingredient and the beneficial substance in resveratrol. It is important to note that pure trans resveratrol does not cause any side effects compared to low purity products which contain emodin and other substances (part of the plant)  that may cause gastrointestinal problems in sensitive individuals. As a reference, the physical appearance resveratrol made of Japanese-knotweed varies according to its purity and therefore may help distinguish between a high purity and low purity product.  Pure resveratrol is white/off-white in color, and is odorless, while low purity resveratrol is brown and has a distinctive odor.  The higher the purity is, the brighter the color will be.  Resveratrol obtained from grapes is very expensive to produce and therefore is only available in low purity of 5-8 percent (trans-resveratrol content).

Trans-Resveratrol Vs Cis-Resveratrol

Both trans-resveratrol and CIS-resveratrol are found naturally in grapes, Japanese knotweed and other plants, however Trans-Resveratrol is the beneficial health substance in resveratrol products, while CIS form has no health benefits. High purity resveratrol contains high amount of trans-resveratrol, while lower purity products contain higher amount of CIS-resveratrol and lower amounts of trans-resveratrol.
Due to the  purifying process low purity resveratrol cost about 40-60% less than pure trans-resveratrol. 

Resveratrol 99% Vs Resveratrol 50%

Resveratrol-99 contains 99 percent of pure trans-resveratrol, the beneficial substance of resveratrol, while resveratrol-50 contains only 50 percent of trans-resveratrol. The other 50 percent contain ingredients that are a natural part of the plant but which have no health benefits. These ingredients include CIS-resveratrol and emodin, which may act as a laxative in some sensitive individuals. These ingredients account for the darker color and stronger odor of resveratrol- 50, as compared to resveratrol-99, which is white, has no odor, and has no side effects. Due to the purification process, resveratrol 50% typically costs about 40-50 percent less than resveratrol 99%.

99% Purity Capsules

99% Purity Capsules

50% Purity Capsules

50% Purity Capsules







Grape Resveratrol Vs. Japanese Knotweed Resveratrol

Most resveratrol sold in the USA and abroad is made of Japanese Knotweed.  Resveratrol made of grapes is NOT superior to resveratrol made of Japanese knotweed, this is just a myth.  Grapes resveratrol is only available in purities of up to  5%-8% trans-resveratrol compared to knotweed which is available in up to 99%-100% purity. Pure trans-resveratrol (99%) made of knotweed does not contain emodin and does not cause any side effects. Why the difference in purities?  Its all in the cost.  Unlike grapes, knotweed grows in the wild and contains higher concentration of trans-resveratrol.  Prior to processing, knotweed can be stored in room temperature, while grapes need to be kept frozen. It takes about 250 kilograms of grape skins to produce 1 kilogram of resveratrol that yields only 5% trans-resveratrol product.

Beware of products that are labeled “made with grape resveratrol”. Most of those products are worthless. Usually, a minuscule amount (a few milligrams) of lowest purity grape resveratrol is added to a low purity knotweed resveratrol, a product which is low in price but also in effectiveness.  Again, it’s another marketing gimmick to intentionally mislead consumers for the sole purpose of monetary gain while the product has no health benefit. Another product that may be confused with grape resveratrol (or resveratrol), is grape-seed, which does not contain resveratrol.

It’s clear that the source of resveratrol is not what matters, what is important is knowing the purity of the product you are purchasing. Remember, it’s the amount of trans-resveratrol that counts, not the source of the product.

Micronized Resveratrol

Micronization is a process of reducing the size of a solid material. Some dietary supplements are water-soluble and therefore their absorption rate in the body is higher than the non water-soluble supplements. Since resveratrol is non water-soluble, the only way to increase its absorption and bio-availability rate is to reduce the size of the particle. The smaller the particle size the higher the absorption rate. Mega Resveratrol’s average particle size is 3 µm (0.003 mm), compared to 170 to 220 µm (0.17-0.22 mm) of standard resveratrol. Clinical studies have shown that micronized particle size increases the absorption rate by up to 210%.

Safety and Dosage

Resveratrol has been used for many years and no safety issues have ever been reported. During the last few years, a number of clinical studies confirmed that taking pure trans-resveratrol in dosages of up to 6,000 mg daily is safe and does not cause any side effects.  Unlike pure trans-resveratrol, lower purity resveratrol may cause gastrointestinal side effects due to the content of emodin which may act as a laxative in sensitive individuals.  Mega Resveratrol contains no emodin.

As a reference, the dosage used in the “Harvard Study” was equal to 23 mg per kg or about 500 mg per 50 pounds of body weight. For example: A person that weighs 150 pounds would take 1500 mg daily. This is just a suggestion based on the “Harvard Study”, not a rule.

Resveratrol may enhance the effect of blood thinning medications (i.e. Coumadin, Aspirin, etc.) and increase the risk of bleeding. Consult your health-care provider before taking resveratrol. Individuals with allergic reaction to grapes, red wine or polyphenols, are advised not to consume resveratrol.

Resveratrol Studies (Resveratrol Health Benefits)


Atherosclerosis (Hardening of the arteries)


Joint disease





Macular Degeneration

Lyme disease


Neurodegenerative diseases


Multiple sclerosis

Cell damage

Calorie restriction mimetic

Harvard Study-(PDF file)


About Mega Resveratrol 99% Trans-Resveratrol

Mega Resveratrol 99 is a pharmaceutical-grade supplement, micronized and purified to a minimum of 99% pure trans-resveratrol.

MegaResveratrol.com was a pioneer in introducing high potency resveratrol products and in setting the standards of voluntary third party independent lab testing for purity and safety.

We offer premium grade natural resveratrol supplements delivered in a vegetarian capsule and in powdered form at an economical price.

At Mega Resveratrol we are always trying to improve our products. For example, most dietary supplements and vitamins are made with “inactive ingredients”. These ingredients are added mainly to facilitate the manufacturing process but they have no health benefits. In some cases, these added ingredients may produce an allergic reaction or they even are unsafe.  All of our resveratrol products are made with no excipient ingredients added. That means vegetarian capsules that contain pure resveratrol with absolutely no additives, binders, fillers or preservatives. (i.e. stearate acid, silica dioxide, etc.), just pure resveratrol.

Our natural resveratrol products are encapsulated in the USA in a GMP facility regulated by the FDA. Every batch is tested for purity by an independent U.S. laboratory. Please refer to the Certification Page.

Mega Resveratrol is a proud supplier of pure trans-resveratrol products to pharmacies and research institutions in USA and abroad.  See the About Us page for details. Our customer’s reviews are independently posted and may be viewed at Google Reviews Page.

President’s letter:

April, 2013

There is a difference between our company and most other companies and it’s not only in the quality of the product. It’s in the story behind the company and its foundation.

In 2003 I was lucky enough to walk out of a hospital alive after surviving a heart attack. I felt like a helpless “walking time bomb.” I knew it wasn’t a question of “if” but “when” my next heart attack would happen. I thought I had two choices – I could rely on miracles or on doctors and statins. Neither one prevented my first heart attack.

For two years I searched for something better than statins or aspirin. I was looking for a natural product that would keep my blood flowing, regardless of my cholesterol levels.

I tried different products and in 2005 I found resveratrol. Back then, the maximum purity available was only 20%. That meant that only 20% of each capsule’s contained beneficial trans-resveratrol, the rest was fillers and impurities. With such low purity levels, to achieve a dosage of 1,000 mg of trans-resveratrol I had to take 20-30 capsules daily.

As you can imagine, I was looking for a highly pure resveratrol product. With my business background, I knew I could produce it and in 2007 we started manufacturing 99% pure trans-resveratrol capsules. I founded Mega Resveratrol because I couldn’t resist offering the same high quality product I wanted for myself to other people. Mega Resveratrol is nothing less than what I would take myself.

That same year I had a routine “stress test” at the hospital. The cardiologist couldn’t understand how and why I performed so well until I described my use of resveratrol.

It’s been almost ten years since my heart attack, and I’ve never felt better. My cardiologist now takes resveratrol, and my company provides high quality resveratrol to satisfied consumers, health-care providers and research institutes in the USA and abroad.

As the owner/founder of Mega Resveratrol, I will never reduce the quality of my product in exchange for monetary gain. I will never sell a product that is less than what I personally use. That is my promise and guarantee!!!

D. Efrat, President