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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, researchers 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.

The potential benefits of resveratrol are based on hundreds of studies, and include assisting with the cardiovascular system, liver, calorie restrictions and mimetic and athletic endurance; prevention against cancer, joint disease, Alzheimer’s, aging, cataracts, macular degeneration, Lyme disease, Neurodegenerative diseases, Parkinson’s, Multiple Sclerosis, and cell damage, as well as having anti-aging and anti-inflammatory properties.

Resveratrol Studies (Resveratrol Health Benefits)

Click on any of the links below to find out more about Resveratrol:

What Should You Know Before Purchasing Resveratrol?

Its not surprising that consumers are confused about resveratrol. Resveratrol is a general name for a product that is available in various prices and purities: 5%, 10%, 20%, 50%, and 99%.  It’s all about labeling. If a manufacturer does not indicate the purity on the label (which most do not), 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 beneficial substance in resveratrol. “Resveratrol” does not mean trans-resveratrol.

If all manufacturers would disclose the purity content of their product, there would be no confusion at all. In principle buying resveratrol is as straightforward as buying gold: Both are available in a variety of purities, but with gold there is no confusion. Why? In order to protect the consumer, the law requires the dealer/jeweler to indicate the purity content by stamping the purity on each item they sell (e.g. 5K, 14K, 24K etc.). Unfortunately, the same law does not apply to dietary supplements and essentially leaves the door open to fraud.

Since the FDA does not require the purity content of dietary supplements to be indicated on the label, it is not surprising that manufacturers who offer low-purity resveratrol do it solely for financial gain, and therefore do not disclose the purity content of their products. Instead, they go a few steps further by using misleading descriptions such as “Extra Strength”, “Super Potency”, “High Purity”, “Pure Resveratrol” and other intentionally deceptive statements while offering low purity resveratrol. It is important to note that most resveratrol sold in the USA and abroad (about 90% of the market) is of a low purity: 20%-50% or less. Remember, if the label does not clearly indicate the amount (or percentage) 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 400-500 mg of trans-resveratrol is the minimum daily amount that is needed to promote the benefits of this product for healthy individuals (an even higher dosage may be required for individuals with certain health conditions). Every label should include the purity information. Below are examples of valid and invalid supplement fact labels in regards to purity.

Consumers should be aware that even though the initial cost of lower purity resveratrol supplements may seem lower, the actual cost can work out significantly higher than the cost of pure trans resveratrol. For instance, consumers who purchase supplements of 50 percent purity must take double the dosage to achieve the same results. Consumers who take supplements of 20 percent purity must take five capsules to match the effectiveness of a single pure trans resveratrol capsule.

Below are samples of “Supplement Facts” labels. In order to emphasis on the purity content, certain information which does not relate to the subject matter (e.g. “Inactive Ingredients”, “Directions”, etc., but legally must be posted as a part of every label), was purposely omitted from the sample labels below.


Label A
















Label B



























When total “Resveratrol” or “Trans-Rresveratrol” content is not disclosed, its impossible to calculated or establish purity content. (Unless indicated as “standardized to ‘x’ Percent” as disclosed in the first two sample labels above.)


FDA Dietary Supplements Labeling Guide >>>


What is “Pure” Resveratrol?

“Pure Resveratrol” refers to a product that should contain only TRANS RESVERATROL, the active ingredient and beneficial substance in resveratrol. It is important to note that pure trans resveratrol does not cause any side effects compared to lower purity products which often contain emodin and other substances (other parts of the plant) that may cause gastrointestinal problems in sensitive individuals.

As a reference for consumers, the physical appearance of resveratrol from 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 (almost) odorless, while low purity resveratrol is brown and has a distinctive strong 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 purities 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 only Trans-Resveratrol is the beneficial health substance in resveratrol products, while its CIS form contains no health benefits. High purity resveratrol products always contain a high volume of trans-resveratrol, while lower purity products contain greater amounts of CIS-resveratrol (and emodin) and lower amounts of trans-resveratrol (the beneficial part of the plant).

Side Effects – (Resveratrol 99% Vs Resveratrol 50%)

Pure resveratrol means the product is 99 percent pure trans-resveratrol – the beneficial, active ingredient of resveratrol. Resveratrol-50 on the other hand contains only 50 percent trans-resveratrol. The other 50 percent is made up of ingredients that are natural parts of the plant but which have no health benefits. These ingredients include CIS-resveratrol and emodin which may cause gastrointestinal side effects such as stomach aches and diarrhoea. The lower the purity of the product, the higher the emodin content and potential risk of side effects. These ingredients also account for the darker color and stronger odor of Resveratrol-50, as opposed to Resveratrol-99, which is white, has no odor, and causes 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 purely a myth. Grape resveratrol is only available in purities of up to 5%-8% trans-resveratrol, as opposed 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 concentrations of trans-resveratrol. Prior to processing, knotweed can be stored at 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 benefits. Another product that may be confused with grape resveratrol (or resveratrol), is grape-seed, which does not contain any 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 the name given to the 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.

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.

Mega Resveratrol was a pioneer in introducing high potency resveratrol products to consumers 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 can even be generally unsafe for consumption.  All of our resveratrol products are made with no excipient (inactive) 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.