The Food & Drug Administration classifies resveratrol and all its supplements as a non-toxic compound, but there are potential side effects that one ought to be aware of. While a lot of studies have been carried out with very little resveratrol dosages to dosages of up to 2 grams and above, the studies didn't show any adverse side effects, but you have to be informed.
These negative side effects have been reported by a few users of the supplements. It might be because of their genetic makeup, or because they used the supplements in combination with other drugs, or even because of an under dosage or over dosage. While chances of the side effects affecting you are very minimal, it's always advisable to follow manufacture instructions, and to discontinue in case such side effects occur.
- Stomach cramping - brought about by using low quality resveratrol supplements that contain high concentrations of an ingredient known as emodin
- Diarrhea - the same causes of stomach cramps cause diarrhea - poor quality supplements
- Joint pains - displaying arthritic signs and symptoms, with stiffing of the joints especially on ankles and wrist
- Feeling numb on fingers and toes (extremities)
- Becoming sensitive to temperature changes
- Discolored urine
- Experiencing a blood pressure rise immediately after taking the supplements
While these are not life threatening, they're known to disappear after a few days. But with good quality resveratrol supplements, these negative effects are less likely to occur. Note that these problems are reported by users and there is no scientific backing as yet. Therefore, these side effects might as well be from a 'placebo effect' wherein an individual is convinced in their minds beyond any doubt that what they're feeling is real, although it might not be the case.
To summarize, the positive effects of taking Resveratrol each day by far outweigh the possible negative effects. Look at it like this: you'll get a tremendous amount of benefits if you run daily, but you'll get tired after each session...