It's not a bad product but you could add individual ingredients together to make up a more effective and cheaper product. You can buy Nattokinase by itself for relatively cheap. Then add an ACE inhibitor at an effective and proven dose and the combination would be much cheaper than what you are paying for that product. The other ingredients aren't going to do much. You can get 500mg vitamin c tablets (especially ascorbic acid which that product contains) for pennies.
This study was based on in vitro observations that naringin isolated from grapefruit induced red cell aggregation and evidence that clumped red cells are removed from the circulation by phagocytosis. The effect on hematocrits of adding grapefruit to the daily diet was determined using 36 human subjects (12 F, 24 M) over a 42-day study. The hematocrits ranged from 36.5 to 55.8% at the start and 38.8% to 49.2% at the end of the study. There was a differential effect on the hematocrit. The largest decreases occurred at the highest hematocrits and the effect decreased on the intermediate hematocrits; however, the low hematocrits increased. There was no significant difference between ingesting 1/2 or 1 grapefruit per day but a decrease in hematocrit due to ingestion of grapefruit was statistically significant at the p less than 0.01 level.
You have to be careful with grapefruits especially on various medications but it has been shown to regulate hematocrit to an extent. Whilst the data is mixed I have seen quite a few people use it with great success. Although I wouldn't be too concerned with your H/H unless they were extremely high.