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Is Too Much Saw Palmetto Bad for You?

Native Americans used saw palmetto to treat urinary problems in men and female breast disorders. In the 1870s, it gained popularity among Western doctors as a treatment for prostate problems and other urologic disorders. The exact mechanism of action remains unknown, but it appears to affect sex hormones, such as testosterone. Most commonly used as a treatment for benign prostatic hyperplasia, it blocks the production of excess androgens, or male hormones, that trigger the growth of prostate cells. This anti-androgenic activity suggests it might benefit other disorders affected by excess production of male hormones, such as acne and polycystic ovary syndrome; however, whether it offers any benefits for these purposes has not been formally studied. Saw palmetto seems generally safe, and staying within doses normally used for this condition will unlikely cause significant problems. If you think taking saw palmetto will address a particular health problem, talk to your doctor about an appropriate amount to take and any associated risks.

How Much is Too Much?

No amount of saw palmetto has been officially deemed ‘’too much.’’ This does not mean however, that taking large amounts will not produce any negative effects or that it will offer any additional therapeutic benefit. Saw palmetto might cause some adverse reactions, and these are more likely to manifest if you take high doses. It is also possible that you could suffer side effects normally not associated with this supplement if you take more than the typically suggested dose.

Dosing Guidelines

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Studies examining the actions of saw palmetto on enlarged prostate have used doses of 160 mg twice a day or a one-time dose of 320 mg of extracts that contain 85 to 95 percent sterols and fatty acids. The University of Maryland Medical Center notes this herb comes in a liquid form but that this type of supplement lacks scientific study, making it difficult to know if it would offer any type of therapeutic benefit. It reports a suggested dose of 5 to 6 mL daily. If consuming actual saw palmetto berries, notes a traditional dose of 1 to 2 g. Unless your doctor advises you otherwise, do not take more than these commonly recommended doses.

Bleeding Risk

Saw palmetto might increase the effectiveness of anticoagulant medications, according to the Memorial Sloan Kettering Cancer Center. Medications such as these have highly individualized doses, and taking supplements that either promote or slow blood clotting -- particularly in large amounts -- could necessitate a change in your dosage. Do not combine saw palmetto with these medications in any amount without talking to your doctor first. It also notes a potential for this supplement to increase bleeding during surgery. If you have a planned surgery, stop using this supplement at least two weeks prior.

Damage to the Liver and Pancreas

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The University of Pittsburgh Medical Center reports cases of individuals who suffered liver inflammation after taking saw palmetto supplements. It notes, however, that animal studies found that even high doses do not appear to damage the liver in any way and that these reactions might have resulted from other factors. This herb might also cause problems with the pancreas, and cases of pancreatitis have been reported. Whether or not the saw palmetto was actually responsible for these adverse reactions is not clear, but if you have any condition that affects your liver or pancreas, if you take medications that tax one or both of them, it is especially important to talk to your doctor before taking saw palmetto.

Decreased Estrogen Levels

Medline Plus reports saw palmetto can lower estrogen levels in the body. Consult your physician before taking saw palmetto if you are currently undergoing hormone replacement therapy or if you are taking contraceptives that contain estrogen. Taking this herb along with estrogen replacement therapy or oral contraceptives might decrease their effectiveness.