Grape seed and skin contain several active components including flavonoids, polyphenols, anthocyanins, proanthocyanidins, procyanidines, and the stilbene derivative resveratrol.  Now, does grape seed extract lower bad cholesterol?
High cholesterol, a significant cardiovascular risk factor, is prevalent in the American population. Many drugs lower circulating cholesterol levels, but they are not infrequently associated with severe side effects. Accordingly, natural means to lower cholesterol levels safely would be welcomed. 
Grape seed proanthocyanidins extract, whose principal ingredients are proanthocyanidins; most are strong antioxidants. Vigana GB and co-workers from University of Ferrara, Italy, supplied 150 mg of a grape procyanidin extract twice a day to healthy male heavy smokers for four weeks. At the end of the study, subjects did not show significant improvement on total cholesterol, bad cholesterol and triglyceride! .............Why? 
In a study of rats suffered from nephrosis, researchers from Children's Hospital of Michigan observed grape seed extract (at dose of 10 mg/100 g) could also lower serum cholesterol and even triglyceride levels.  Please, that “1 pound = 453.6 grams” and the dose is 40 mg of grape seed extract per 100 g of rat weight, this means “human need to take a few grams of that grape seed extract to achieve the effect of lowering bad cholesterol”.
Combined with other actives, that one may not need to have such high doses to low bad cholesterol. In 2000, researchers from Georgetown University Medical Center supplied 40 human subjects twice a day with high cholesterol (210-300 mg/dL) with either placebo, chromium polynicotinate 200 microg, grape seed extract 100 mg, or a combination of chromium polynicotinate and grape seed extract at the same dosage. Two months later, the average percent change in the total cholesterol from baseline among groups was: placebo -3.5%, grape seed extract -2.5%, chromium polynicotinate -10%, and the combination -16.5%. Again, the combination of chromium polynicotinate and grape seed extract significantly lower bad cholesterol, i.e. LDL, when compared to placebo. 
A few more words…..
The effectiveness of a grape seed extract depends on its extraction ratio, purity, dosage form, composition, dose and the users’ conditions as well. Discuss with your doctor before taking any supplements.
___________________________________________________________________________________________ Reference:  Preuss HG, Wallerstedt D, Talpur N, Tutuncuoglu SO, Echard B, Myers A, Bui M, Bagchi D. Effects of niacin-bound chromium and grape seed proanthocyanidin extract on the lipid profile of hypercholesterolemic subjects: a pilot study. J Med. 2000;31(5-6):227-46.  Mattoo TK, Kovacevic L. Effect of grape seed extract on puromycin-aminonucleoside-induced nephrosis in rats. Pediatr Nephrol. 2003 Sep;18(9):872-7. Epub 2003 Jun 26.  Vigna GB, Costantini F, Aldini G, Carini M, Catapano A, Schena F, Tangerini A, Zanca R, Bombardelli E, Morazzoni P, Mezzetti A, Fellin R, Maffei Facino R. Effect of a standardized grape seed extract on low-density lipoprotein susceptibility to oxidation in heavy smokers. Metabolism. 2003 Oct;52(10):1250-7.  Nassiri-Asl M, Hosseinzadeh H. Review of the pharmacological effects of Vitis vinifera (Grape) and its bioactive compounds. Phytother Res. 2009 Jan 12
manufacturer, you should be able to find the contact information on the label.
There are always new information. Please, send me an email (email@example.com) to correct my mistake(s). Reasonable care has been taken in preparing this document and the information provided herein is believed to be accurate. The information is not intended to be a substitute for professional medical advice. It is important to seek the advice of a physician about any medical condition or symptom or the benefits and side effects of a supplement or a drug product. Finally, please, do not transfer the article to other website. Thank you. ALL RIGHTS RESERVED.