Dopamine is every guy's favorite neurotransmitter. Oo la la - it's the "reward and pleasure neurotransmitter." Of course, if we're not careful, it can turn almost any one of us into one of Pavlov's dogs if we're not careful.
But dopamine is a lot more than just the pleasure hormone. It can actually boost your erections. That's right - dopamine agonists (receptor stimulator) have been studied as actual erectile dysfunction medications. I have had men write in who have taken the dopamine precursor supplement tyrosine - see below - and restored their morning erections. Look at what Wiki wrote about Apomorphine, a dopamine agonist:
"For treatment of erectile dysfunction, it is believed that dopamine receptors in the hypothalamic region of the brain are the main target, as although dopamine receptors in the penis do facilitate erection, they do so far more weakly than those in the brain."  Yes, indeed, the brain has as much to do with erections as the penis.
However, many men living the modern, industrialized lifestyle can find their dopamine levels actually depleted. Several studies have found that higher fat diets, for example, create insulin resistance in the brain, which can significantly drop dopamine levels.  Sitting can lead to depressed dopamine levels as well.  Addictions to fatty and sugary foods, based on an animal study, can lead to overstimulation of the brain reward system and dulled dopaminergic response. 
And the signs of this are everywhere. Migraines are tied to lower dopamine levels. RLS (Restless Leg Syndrome) has also strongly been linked to low brain dopamine levels. Most studies show the prevalence of RLS to be between 5-10% of the adult population for example.  Furthermore, researchers are now discovering that depression, a modern epidemic by any standards, may be related in many individuals to low dopamine levels.  This may explain why SSRI's are so often ineffective.
Is dopamine important? You bet it is: every bit as important to the male as testosterone. Dopamine plays a strong role in libido, motivation, energy, learning and cognition.
Adding to the issues are the fact that there is so little information on ways to naturally raise your dopamine. In my opinion, the great majority of the information out there grossly misses the mark. You will find most sites recommend various supplements, such as L-Theanine (of green tea fame), NADH, Mucuna Pruriens and Withania somnifera (Indian Ginseng). I've even seen cough syrup recommended: the active ingredient, Dextromorphan (DXM), is a dopamine agonist (stimulator)!
CAUTION: Watch out for DXM. Many experts think it leads to Olney's (brain) lesions. And cough syrup is no longer recommended for young children.
In my opinion, these are all avoiding most of the root causes of dopamine depletion. You have to ask yourself if you are seriously going to take these herbs and supplements for the rest of your life? How do you know what the side effects are after decades of use?
Below I list easy ways to boost brain dopamine levels and, unless you have significant neurodegenerative disease, should naturally restore your dopamine levels without a lot of pills and capsules:
1. Exercise. Exercise leads to a dramatic boost in dopamine almost immediately after exercise.  Our bodies were made to move and exercise and it simply isn't natural for us to be sitting for hours in front of a TV or computer. Most of the supplements, herbs and pills to boost dopamine will simply be trying to cover up the fact that we are putting our bodies in motion throughout the day.
2. Stand. If you can't exercise for some reason, then at least stand for awhile. Standing has been shown to be very effective in raising dopamine levels. 
3. Sex. It's no secret that an orgasm boosts dopamine and a whole lot of other brain neurotransmitters. In fact, researchers have shown that an orgasm stimulates the same parts of the brain as that stimulated on the opiates such as cocaine and heroin.
4. High Fat Diets. As mentioned above, watch out for higher fat diets mentioned above as researchers know this can cause issues if overdone. Note that all the Paleo Diets can easily turn high fat. A lot of guys on a Paleo Diet are avid exercisers and so this may compensate, but beware.
5. Eat Less. Interestingly enough, certain stressors can counterintuitively raise dopamine levels. Normally, we think of dopamine as the "reward neurotransmitter." However, a sleepless night can increase dopamine.  And so can a reduction in calories. Researchers believe that reducing calories can help Parkinson's patients, who have experienced 80+% destruction of their dopamine-producing cells.  Most of the supercultures with extreme longevity in the world - see my review on John Robbin's Healthy at 100 - eat lower levels of calories and their brains are largely preserved into their senior years without disease.
6. Flavanoids. A diet rich in flavanoids (berries, tea, raw cacao, etc.) have been found to protect the brain from Parkinson's.  This means that the cells in the substantia nigra, which produces brain dopamine, have been substantially guarded from the oxidative damage to heavy metal and free radical - see below - damage. The more of these healthy cells you have, the higher your brain dopamine levels are going to be.
7. Metals and Excitotoxins. Avoid heavy metals. Iron and copper have now been heavily implicated in causing Parkinson's.  The copper in our pipes, for example, slowly accumulates in tissues and leads to increased oxidative damage in the brain, especially those of the substantia nigra.
8. Excitotoxins. Watch out for excitotoxins. There are many reasons that the blood-brain-barrier (BBB) can be compromised and, if it is, the MSG, autolyzed yeast extracts, aspartame and hydrolyzed proteins (in standard wheys, fast and processed foods) will rip through your neurons like a blender. See my links on Testosterone and Excitotoxins, the Blood-Brain-Barrier and Excitotoxins and Fast Food, Excitotoxins and Whey and Excitotoxins for more information.
9. CoQ10. CoQ10 is a relatively safe supplement that appears to preserve brain dopamine levels. This is one of the reasons that it can play a role in Migraine Prevention and has been found helpful in the treatment of RLS (Restless Leg Syndrome) as well. Preliminary evidence shows that it may slow the progression of Parkinson's  and can provide relief for those with already existing Parkinson's.  The only caution that I know of with CoQ10 is that one study showed that higher levels were tied to breast cancer risk.
10. Protein. If you read my link on Food and Appetite, you will find that protein, if done right, tends to increase brain dopamine levels.
11. Zinc. Zinc has many talents, but one its many benefits is regulating dopamine levels. Getting more zinc may help and this link on Zinc and Testosterone explains how.
12. Tyrosine. Tyrosine is an amino acid very common in high protein foods and even gets its name from the Latin word for cheese. It also can give some people a nice boost in dopamine. Long term safety is not really known and it is recommended that one experiment with 250 mg or at the most 500 mg on an empty stomach (or with a low protein meal). Side effects reported include heart flutter and restlessness. (It is the awareness and alertness neurotransmitter after all.)
13. Sleep. Make sure you get your sleep. Researchers have recently found in several studies that lack of sleep decreases dopamine receptor sensitivity, which then has many negative downstream effects. For more information see my link on Sleep and Dopamine.
14. Music. "Sex, Drugs and Rock 'n Roll!" What do those have in common? They all boost dopamine. Actually, researchers did not know definitively that music boosted dopamine until a 2011 study showed conclusively, using radioactive chemicals that bound to participants' dopamine, that not only did music cause the brain to release dopamine but even the anticipation of music (that we like) could do the same.  Talk about a cheap and easy brain booster!
15. Mucuna Pruriens. This prolactin-controlling, dopamine-increasing extract from the legume called the "velvet bean" has even been used by some in treatment of Parkinson's. Animals studies show that it increase dopamine in certain key areas of the brain.  It will also likely help many men with infertility and testosterone as well.
CAUTION: Melatonin Supplementation. Obviously, getting adequate melatonin before bed is a good thing. Furthermore, supplemental melatonin is part of a multisupplement Sleep Aid cocktail that was recently found to be effective in patients suffering with insomnia. Nevertheless, some caution with supplemental melatonin may be in order, since it low dopamine levels.  Normal melatonin is important, though, and its antioxidant powers likely protect the cells of the substantia nigra.
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