Grape seed extract is touted as holding the key to improving an array of health conditions, from hemorrhoids to diabetes to cancer. Some extract marketers and purported health news internet sites even promise that it will boost your testosterone levels. However, the jury is still out on many of grape seed extract’s effects. You’ll find grape seed extract available in liquid, tablet and capsule form. Always consult a doctor before trying a new supplement.
Grape seed extract contains oligomeric proanthocyanidin complexes, which are commonly called OPCs, linoleic acid, which is an omega-6 fatty acid, vitamin E and flavonoids. It also has some resveratrol, a compound that’s similar to the OPCs, according to the University of Maryland Medical Center.
While grape seed extract is touted as beneficial for treating a host of health issues that are related to free radical damage such as cancer and heart disease due to its combination of antioxidant compounds like OPCs, just one compound in it is singled out as offering possible testosterone-boosting benefits. While grape seed extract does have some resveratrol, this substance is mainly found in grape skins. Some grape seed extract formulations offer “grape seed extract with resveratrol.”
Much of the research backing resveratrol’s potential testosterone-boosting benefits has been done on rats, not humans. For example, S. Shin, lead author for a 2008 study published in the “Archives of Pharmacal Research,” found that resveratrol raised blood testosterone concentrations along with testicular sperm counts in rats. Another study in the 2005 “Journal of Nutrition” found that rats that received resveratrol daily gained enhanced sperm counts as well as higher testosterone levels, says lead study author M. Emília Juan. Resveratrol also has a theoretical anti-estrogenic effect, according to Oregon State University. Despite the fact that benefits found in animals don’t always translate to benefits in humans, you’ll find websites citing these studies and their theoretical anti-estrogenic activity as proof that resveratrol will boost your testosterone levels.
Some of the studies that show benefits in humans that are attributed to resveratrol involve removing cells from people and combining them with the substance in test tubes, notes Holly Phaneuf, author of “Herbs Demystified.” These don’t always translate into realistic results because of the way the body metabolizes utilizes resveratrol, Phaneuf notes. Your body may metabolize it too quickly for effects that appear in test tubes to show up in real life. As of 2010, little was known about resveratrol in humans, notes Oregon State University. In all, scientific evidence is lacking for using grape seed extract to boost testosterone in humans and for most of the conditions it theoretically improves, according to UMCM. In fact, the only good evidence is related to using the extract to treat edema and chronic venous insufficiency, note the experts at UMMC. The OPCs in grape seed extract show some promise for treating erectile dysfunction, notes Steven Bratman, author of the “Collins Alternative Health Guide.” However, this is theoretical, similar to the potential boost to testosterone levels or the extract’s potential in treating many other health conditions.
If you take grape seed extract in an effort to boost your testosterone levels, it’s considered safe at recommended doses for up to 12 weeks, advise the experts at UMMC. Doses range from 10 mg to 300 mg a day, so it’s important to consult a doctor before determining the best dose for you to try. Also, talk to your doctor about possible drug interactions. Few are reported, but the OPCs in the extract may increase your risk for bleeding if you take it along with blood-thinning medicines such as aspirin or warfarin or if you have a bleeding disorder.
- PubMed: “Archives of Pharmacal Research”; trans-Resveratrol relaxes the corpus cavernosum ex vivo and enhances testosterone levels and sperm quality in vivo; S. Shin et. al; 2008
- “Journal of Nutrition”: trans-Resveratrol, a Natural Antioxidant from Grapes, Increases Sperm Output in Healthy Rats; M. Emília Juan et al.; 2005
- Oregon State University: Resveratrol
- “Herbs Demystified”; Holly Phaneuf; 2005
- University of Maryland Medical Center: Grape Seed