Hello,
This is my first post on this forum but I think this information could be relevant to somebody.
I decided to start resveratrol supplementation, but since I don't quite believe in the information on the label, I decided to test what is a real concentration of resveratrol in commercial supplements. You can find results below in the following order: company name, batch number, declared concentration, actual concentration.
Swanson Ultra - ??? - 100mg - 109mg
Swanson Ultra - 209085 - 250mg - 281mg
Olimp - 01630314 - 200mg; 200mg
Puritan's Pride - 399272-06 - 100mg - 101mg
Alfa Vitamins - 16660 - 500mg/250mg - 37mg
Myvitamins - 61956 - 125mg - 41mg
Myvitamins - ??? - 125mg - 81mg
Source Naturals - FG18143 - 100mg - 87mg
In case of Alfa Vitamins the label stated "Resveratrol 500mg" but in the Suplement Facts table there is information that there are 500mg of extract with 50% resveratrol content.
To analyzed resveratrol concentration I used HPLC with C18 column. Due to methodology I choose I did not determined concentration of each isomer (cis- or trans-) but the total resveratrol content. The results are average from 3 capsules/tablets. I also did additional analysis for fourth capsule/tablet if concentration was below the declared value like in case of Alfa Vitamins or Myvitamins. In some of the results there is a missing batch number. The reason for that is that some time ago I took resveratrol and I left few capsules to analyze in the future but I throw away package with batch number. In the attachment I add an exemplary result for Myvitamins 125mg (bright) and Swanson 100mg (dark). The lower the peak area the lower the concentration.
I am planning to put those results on another forums, since there aren't many information about declare vs real resveratrol content.
I am sorry if I make any spelling or grammar mistakes. English is not my native language.
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Edited by LC-f, 01 September 2015 - 02:46 PM.
