For many people icariins would clearly seem to be the plural of icariin but with Horny Goat Weed (HGW) it’s not that simple! Confusingly, although they are both extracted from the Epemedium plant, they are two different compounds that represent the difference between a good or not so good HGW.

What’s the difference?
The best quality icariin extract is processed only from the leaves but lesser icariins extracts most often intentionally use the entire plant and are considered to be cheap and low quality alternatives. They are rated on the percentage of all plant matter used in their production that may contain as little as 5% to 10% useful icariin flavonols and a large percentage of other mainly ineffective compounds. On the other hand, a quality HGW will be a properly processed Epemedium extract that uses only the leaves with a much higher content of pure icariin flavonols.

What percentage works best?
To further confuse the issue, the effectiveness of icariin in HGW as a dietary supplement is not parallel to increases in icariin content percentage. Like most flavonols, icariin is at its most active when it is still contained within a portion of its original constituent biological parts, meaning that if all the other constituent parts are removed during extraction, leaving 100% icariin flavonols, then those flavonols naturally become less stable and as a result less effective. This is why you should look for an extract of about 50% icariin flavonols as this is considered the optimum effective range. Lower percentages can be expected to be less effective but higher percentages can suffer from “over-extraction” and a less stable extract that can also prove to be less effective than the optimum percentage of around 50%.

Tonvara HGW:50 is an effective Horny Goat Weed extract that is produced to the highest ISO standards with an optimum 50% pure icariin content.