Hopefully, you've already my Top Five Erectile Supplements with solid research and few side effects. These top five can heal about two thirds to three fourths of guys with erectile dysfunction according to the studies. However, there are a number of other very helpful supplements that can improve erectile strength directly and/or indirectly that I wanted to include as well:
Don't forget to read my links on the following, all of which can be just as helpful as supplementation: Erectile Repair Guide, Kegels, the Erectile Strength Diet and Exercise. Always get to the root of your problem or eventually heart and arterial disorders will stop your sex life dead in its tracks.
Here is a list of secondary erectile dysfunction supplements with some reasonable evidence:
1) Caffeine. Believe it or not, caffeine may actually improve erectile dysfunction. This theory is still in the beginning stages, but a recent study on diabetic rats showed that "caffeine consumption improved the erectile function of diabetic rats by up-regulating cavernous cGMP".  Be careful about tanking up on caffeine though: it is too early to tell if the study results will translate to non-diabetic humans.
2) Citrulline. Citrulline is an amino acid present in watermelon, fish, eggs and a few other foods. It is a pre-cursor, or building block, of L-Arginine and, as such, is an erectile dysfunction supplement that increases blood flow and Nitric Oxide throughout the body. I have been able to find no side effects at this point, although one would expect that it would have, at a minimum, some of the profile of L-Arginine itself. No one really has much of a doubt that Citrulline will increase Nitric Oxide levels - the debate is really "how much?". Many individuals have plenty of Arginine in their systems and, in that case, citrulline is unlikely to help much. If you want a more natural route, a recent study showed that citrulline exists in substantial quanitites in watermelon rinds.  That ought to get you some attention at your next BBQ, when you chow down on a half dozen watermelon rinds while everyone else is enjoying coleslaw and beer butt chicken. You may have the last laugh, though, as a Web MD article s states that "a typical 4-ounce serving of watermelon (about 10 watermelon balls) has about 150 milligrams of citrulline". In other words, you don't even have to eat the rind to get a goodly amount.
3) Vitamin C. Several studies have shown that Vitamin C keeps Nitric Oxide in your system longer, something almost any good erectile dysfunction supplement should do, and thus should be a mild help with erectile dysfunction. One study showed that hypertensive patients actually had a measurable increase in dilation of the veins in the forearm for patients given Vitamin C.  This should translate to dilation of the arteries bringing blood to the penis as well. CAUTION: Vitamin C has done well in many studies and has many possible side effects including cancer and hardening of the arteries. Read about The Possible Dangers of Vitamin C before you make your decision to take it. (And consult with your doctor of course.) NOTE: Regular Vitamin C is very acidic and hard on the stomach: you may want to consider the Ester-C form for just that reason if you do decide to take it. One interesting benefit of 1.5 g/day of Vitamin C i is that it actually decreases cortisol levels and cortisol lowers testosterone and is very hard on the brain.
4) CoQ10. A study from Germany showed that men with sub par endothelial function were helped by taking CoQ10. That should translate to improved erectile dysfunction. What they found was that blood flow was increased to arm vessels simply by increasing this one nutrient.  This was verified by one recent European study showed something similar: taking 300 mg/day of CoQ10 helped endothelial function by relaxing veins - yes, that means more blood flow throughout the body including the penis - and increasing the body's key antioxidant SOD (which protects your incredibly valuable Nitric Oxide). .  So, yes, even a run-of-the-mill, non-exotic supplement like CoQ10 can improve erectile dysfunction and impotence.
5) Folic Acid. A recent meta-analysis, a study of studies, revealed that folic acid supplementation improved endothelial function and that should improve erectile dysfunction as well. Better blood flow and arterial dilation are good for your sex life and should improve erectile dysfunction while it's at it. After all, you want all the veins in your body, especially the ones in the penis, to be able to expand easily and allow the blood to move freely. Furthermore, researchers found that the higher the dose, the better the result.  Scientists speculate that folic acid's potency may stem from its ability to lower homocyteine levels, which is one of the leading predictors of heart disease. In fact, scientists found that elevated homocysteine levels were as strongly correlated to heart disease as high cholesterol and triglycerides.  Folate also protects the Brain as well. CAUTION #1: There is some new evidence that too much Folic Acid can lead to colon cancer.  See this link for details. But, it should be added, many studies have found that Folic Acid supplementation actually lowered cancer levels.  Again, though, the safest way is always to get what you need through what you eat. CAUTION #2: You may have read that Vitamins B6 and B12 can lower homocyteine levels as well. Be careful about taking B6 and B12 supplements. These usually come in megadoses that can cause memory damage and/or exacerbate acne. See this link f for details.
6) Magnesium. Make sure you are getting enough Magnesium. Studies have shown that adequate magnesium can decrease some of the effects of Metabolic Syndrome and lower inflammation (c-Reactive Protein, a.k.a. cRP) levels which are devastating to your endothelium.  To improve erectile dysfunction and impotence, you definitely want to consider Metabolic Syndrome one of your arch-enemies. If you're eating a healthy diet, such as the Mediterranean Diet, that is so often recommended on this site, then you have little to worry about. But if you're eating like a typical Westerner, consider taking this inexpensive supplement. Magnesium is so critical that I have devoted a separate link to the subject.
7) Gingko. Gingko, like Pycnogenol, strengthens the activity of Nitric Oxide Synthase (NOS), making it a viable erectile dysfunction supplement.  Furthermore, animal studies have shown that Gingko relaxes in a dose-dependent fashion arteries, including those all-important ones supplying blood to the penis. Direct evidence that Gingko improves erectile dysfunction and impotence in a significant way is still lacking, but any herb that increases Nitric Oxide will help males struggling in this area. (This is an herb can be purchased inexpensively even in places like Wal Mart.) NOTE: Gingko Biloba is often tauted as improving erections in men with erectile dysfunction that had resulted from taking antidepressants. However, the studies have actually shown mixed results in this area. CAUTION: Care should be exercised with this supplement as Gingko thins the blood and has several drug interactions including NSAIDs and anticoagulants.<.
8) Tongkat Ali/Eurycoma Longifolia Jack.&. A libido enhancer worth mentioning because it has done well in studies on rats and because it is frequently in ex. A libido enhancer worth mentioning because it has done well in studies on rats and because it is frequently in ex. A libido enhancer worth mentioning because it has done well in studies on rats and because it is frequently in ex. A libido enhancer worth mentioning because it has done well in studies on rats and because it is frequently in expensive supplement preparations in health food and nutritional stores. No human studies have been done to date from what I have read, except for one that shows an increase in muscle mass . And, unfortunately, the animal studies were all conducted by one researcher.
9) Tribulis Terristris This is much-hyped in nutritional stores and bodybuilding sites as a testosterone booster. The truth is that it has a few animal studies behind it in this area but little else. Tribulis works on testosterone by increasing Leutinizing Hormone, but this has a muted effect the older a guy gets. However, Tribulis is an old friend and a lot of guys swear by it. The reason is that Trib is very likely a jack-of-all trades. We cover that here in a link on Super Sexual Herbs. .
10) Yohimbe. . One of the ways this herb seems to work is by increasing blood pressure. That’s the last thing anyone, especially those over 40, needs. So, yes, this can improve erectile dysfunction and impotence in the short term. However, it is probably dangerous to your long term health.
11) Chrysin. Estrogen can crowd out testosterone and so an estrogen inhibitor can boost testosterone. 6-OXO was recently banned by the FDA, leaving Chrysin, which is a questionable estrogen-inhibitors at best. For a more detailled look, read this link on Estrogen. .
12) Saw Palmetto/Pygeum/Stinging Nettle. All three of these herbs have a solid and generally safe track records and all three are known for their ability to block the enzyme that conversts regulard testosterone into DHT, one of the male androgens infamous for causing hair loss and enlargening the prostate. This is exactly how the hair restoration drug Propecia (formerly called Proscar) works, i.e. by blocking this same enzyme. But here is what your doctor and pharmacist will not tell you: Propecia can result in estrogen-like symptoms including enlarged male "breasts", loss of sex drive, decreased semen volume, erectile difficulties and so on. Saw Palmetto, which is the "natural" equivalent of Proscar produces these same symptoms in a certain percentage of men. Pygeum and Stinging Nettle also block this same enzyme and thus, to one degree or another, probably produce these estrogen effects. Bottom line: these herbs are simply not worth the risk. Start wearing a hat if you're that sensitive about your scalp.
13) Carnitine. An Italian study demonstrated that taking 2 g/day of propionyl-L-carnitine along with 2 g/day of its cousin acetyl-L-carnitine, actually improved erectile function more than that of the a group taking testosterone.  A later study showed that 2 g/day of propionyl-L-carnitine actually significantly improved erections in men who were unresponsive to Viagra alone.  And, as if you wouldn't be happy enough with these results, Carnitine has also demonstrated mood and energy improvements as well. Carnitine is abundant in animal sources: a 3.5 oz serving of beef has a little over 90 mg, pork a little over 20 mg and chicken and dairy a little over 3 mg. A strict vegetarian diet will have very low levels of ingested carnitine. CAUTION: : This supplement should probably be regarded as a short term solution because 1) acetyl-l-carnitine increases free radical damage (which is why it is generally coupled with alpha lipoic acid) and 2) there is some evidence that it may interfere with thyroid function.
CAUTION: Note that this form of carnitine does not appear to be available on a retail basis. Also, carnitine has recently been implicated as a counterintuitive cause of heart disease. It turns out that bacteria love carnitine for fuel and increase levels of TMAO in your blood. TMAO, in turn, "enables cholesterol to get into artery walls and also prevents the body from excreting excess cholesterol."  Carnitine is found in high levels in beef and pork and meat eaters should be cautious in consuming red meats such as this.
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