Maybe you didn't sleep so well last night, with an unruly spring poking you in the back and your clock ticking thunderously. Perhaps the massive burrito you ate for lunch is now singing the refrain to "Cielito Lindo" over and over as you lapse into an afternoon food coma. Or your boss "suggests" that you stay late to finish the maddeningly boring last bits of the big project. You need a boost to jolt yourself out of your lethargy and amplify your productivity.

Well, you can overclock a PC for better performance, so why not overclock yourself? Is there a simple way to speed up your metabolic rpm, accelerate your mental gigahertz, or increase your intellectual bandwidth? And can you achieve the performance upgrade without shorting out your power supply or overheating and fusing your CPU, thereby transforming yourself into a featherless bipedal doorstop.

In the interest of semiscientific inquiry--and because I'll eat just about anything to put food on the table (wait a minute...)--I took a look at a host of performance enhancers from the mainstream to the exotic to the just plain wacky. My mission: to see which ones provided a boost without inducing psychosis. For each product, I ingested a standard serving in the morning, in lieu of coffee. Enduring the resulting jitters, shakes, nausea, hallucinations, palpitations, and heebie-jeebies, I sweated out the bad stuff to bring you the good stuff.

Though the efficacy of all of these supplements remains largely a matter of conjecture, energy drinks are at the center of a growing controversy over the unknown effects that large quantities of herbal energy boosters can have on the human body. I can't stop you from trying any of these products, but I urge you to exercise caution if you're inclined to experiment--and not to experiment at all if you are under 18, are pregnant (or trying), or have any health problems. With that caveat out of the way, here's the straight dope on so-called smart foods. And remember: I'm not a real doctor.
Drinking It All In

The most accessible over-the-counter power-up--and perhaps the most controversial--is the energy drink. If you're looking for a quick jump-start, just crack open one of these stimulant-rich solutions. Packed with potent pep in the form of sugar, caffeine, and guarana, plus vitamin C and B vitamins, energy drinks can deliver an undeniable boost. But are they safe? Few topics in the nutrition world are more hotly contested.

Cynthia Sass, a registered dietitian who holds a masters degree in public health, says that it all depends. "Caffeine is generally considered safe, but when multiple stimulants are combined, even healthy, young, fit people can experience side effects including spikes in blood pressure and heart rate," says Sass. And energy drinks do pile on the stims. Guarana includes its own hidden dose of caffeine but is listed separately from regular caffeine; ginseng is another natural stimulant. In addition, the gargantuan cans that energy drinks are sold in usually contain two full servings (and sometimes more), so it's easy to exceed a dosage that's comfortable or safe for you.

Of course, the drinks themselves vary widely in flavor and efficacy. As you wander the minimart before your second shift, you encounter a visual cacophony of mysterious concoctions that evidently target very precise subgroups of the sleepyhead demographic, ranging from NASCAR moms to death-metal tweens. Which one should you consume to replenish your essences? I grabbed several of the most popular drinks (sans the ubiquitous Red Bull; I figure that if you're interested in it, you've already tried it) to test the effects--good or bad--on my own physiology.

(Confused about the vaguely medicinal-sounding herbal additives--such as taurine, guarana, and L-carnitine--that crop up in the lists of ingredients? Jump to the "Field Guide to Energy Additives" for a primer on these ingredients.)

Nos High Performance Energy Drink
Taste: 8
Energy: 2

With its low carbonation (typical of energizer drinks), Nos resembles a peach Orangina, making it pretty pleasurable to drink. When cold, it verges on refreshment. It comes fortified with caffeine, ginseng, taurine, and both vitamin C and the B group of vitamins. But in my test, its energy boost seemed rough and short-lived. It certainly increased my energy and awareness, but those effects were attended by a shakiness that was better suited for staccato tapping on a tabletop than typing an e-mail. In short, it was a jaggy rush followed, inevitably, by a case of the yawns.

Glaceau Vitamin Energy (Tropical Citrus)
Taste: 6
Energy: 8

Tropical, but not really citrus, this elixer has more of a passion-fruit nose with a pineapple LifeSavers finish; fans of bubbly will be disappointed to learn that it was nearly devoid of carbonation. Glaceau eschews a mishmash of uppers in favor of "natural caffeine," B and C vitamins, taurine, and ribose (a simple sugar), with good results. The ensuing lift is mellow, with no sharp edges and no crash. Imagine the Fruit of the Loom guys singing in an old-timey barbershop quartet just behind your hypothalamus and you'll have the intensity gauged just about right.

Monster Lo-Carb Energy
Taste: 5
Energy: 7
I ducked and covered in the face of goofy Monster flavors such as Kaos, M-80, and Assault, opting instead for Lo-Carb, which has all the energy goodies but just 10 calories per serving. This variety tasted the most medicinal, with the bubble-gum tang I associate with guarana and a slightly artificial aftertaste. It got my front-side bus humming (without adding to my front-side bulk). With B vitamins and a vague energy blend of the usual suspects, this potion amps up the energy without impelling you to stake out your apartment in anticipation of the carb monsters' arrival.

Full Throttle Fury
Taste: 2
Energy: 4

Coca-Cola's entrant, Full Throttle, is an inferior product bolstered by the brand's shelf power. Fury, the variety I tried, was semipalatable at first, but it soon evolved into an orange-flavored sore throat. The fluid's weak energy boost may help explain why Coke doesn't detail the proportions of the various stim ingredients, instead referring to them as a "3,000mg blend" of caffeine, guarana, carnitine, taurine, ginseng, and sucrose (that's table sugar, folks). I drifted for hours in a limbo of faint nausea while waiting for my stomach to flip right-side up again. Infuriating.

Rockstar Juiced Pomegranate
Taste: 10
Energy: 8

By far the best-tasting energy drink in my roundup, Rockstar's Juiced may be one of the more healthful ones, too, since a pleasing blend of pear, apple and pomegranate juices accounts for 50 percent of its volume. It got my platters spinning with all of the standard-issue stimulants, plus such relatively exotic boosters as ginkgo biloba and milk thistle extract. The resulting lift was characterized by a calm clarity without nerviness or a sudden fall. With this stuff in my tank, I could imagine finding the White Pages a fascinating read. One word of advice, though: Don't dribble the inky, scarlet drink down the front of your favorite T-shirt.

Bawls G33k B33r
Taste: 2
Energy: 8
This r00t-b33r-themed guarana-and-caffeine drink has a medicinal edge that lasts beyond any of the more palatable flavors, but only the first and last sips are truly blech-alicious. Once taken internally it performs to spec, giving you a guarana-and-caffeine-fueled energy jolt that lasts a surprisingly long time. I drank mine for breakfast, and within 5 minutes I was preternaturally alert and awake. A couple of hours later, I could tell that all of my gears were still engaged--and without any of the tense jitters associated with most high-caffeine drinks. If you can get past the somewhat disgusting aftertaste, this drink will wake you up and giving you a bit of jitter-free focus. In fact, it will do so even if you can't get past the aftertaste.

Brain Toniq
Taste: 6
Energy: 2
This caffeine-free mix of choline, plant extracts, algae, and organic agave nectar doesn't taste too bad, and it doesn't get you all loopy and jittery on caffeine. The operating philosophy here is that, rather than flooding your system with misdirected, short-term energy, Brain Toniq helps you think. I don't know about that, but it tastes like a melange of passion fruit, watered-down Hawaiian Punch, and watermelon juice: flavorful up front, but ending with the consistency of left-open-for-a-day soda. The beverage helped me focus a bit. I didn't write complicated algorithms or make mind-blowing discoveries after drinking it, but it did chill me out. In fact, I felt restless before drinking Brain Toniq; but after consuming it, I felt content to hang out at home and write reviews.

Potions, Powders, Pills, and... Chips?

Not all energy boosters come in tall aluminum cans. Here are four alternative ways to amp up your mind and body.

Living Essentials 5-Hour Energy (Berry)
Taste: 8
Energy: 8

You've probably seen these little bottles at the corner store by the register and wondered if they were any good. Wonder no more--they're not bad. They taste less medicinal than I had expected, and they go down in one or two gulps. The liquid concoction hit me with eye-opening speed, lifting the morning fog with gale-force winds. This clean-burning fuel has also only 4 calories, one-fiftieth of the load of a typical 16-ounce energy-drink can. But it should be called 3.5-Hour Energy--that's when the Sandman shuffled softly back my way.

TwinLab Choline Cocktail
Taste: 4
Energy: 10

Holy smokes: This stuff tastes terrible! Sickly sweet and thick to boot--four tablespoons of this powder could make a spoon stand up in water, and the potion never loses its unpleasant, vitamin-laced flavor. A giant of a bygone era, Choline Cocktail was at the forefront of so-called smart drinks in the '90s, and inveterate supplement-takers are accustomed to chugging ill-flavored drinks--back then, it tasted relatively good. But Choline Cocktail's assaultive flavors aside, a laundry list of vitamins, plus choline, DMAE, ginkgo, and guarana, grab you by the ears and shake you into razor-sharp alertness. And it does taste better than most laundry.

Now Brain Elevate
Taste: N/A
Energy: N/A

The one stand-alone tablet I tested for this story is devoted solely to mental enhancement, so I added it of a small cup of coffee. Brain Elevate recommends a regimen of a single pill one to two times daily. The vegetarian, mostly herbal formula contains choline, ginkgo, rosemary leaf extract, and gotu kola. It doesn't stimulate the central nervous system, but I did notice a sense of increased clarity and vigilance. And though it's pricey at $22 per 60-capsule container, one bottle can last for 30 to 60 days of regular use--and longer if you skip it on the weekends.

Engobi Energy Go Bites
Taste:
5
Energy: 7

Got a problem with drinking? Then stop spilling coffee in your lap and get your caffeine fix in a solid, crunchy form. Engobi Bites come in two flavors: Lemon Lift and Cinnamon Surge. Regrettably, both flavors offer the savor and texture of deep-fried cereal, with a Splenda aftertaste. Promotional material on the bag--obviously meant to replicate the trust-me enthusiasm of an unsolicited endorsement--says, "Prepare to get wired. I mean really wired," and it's not far off the mark. [Editor's note: He's not kidding. These things taste like pure, fried sucralose, and they gave me a lasting case of the jitters in my fact-checking tests.] Scarfing down a package left me a bit twitchy and uncomfortable (but by no means tired). Occasional grazing through an afternoon might be a good way to keep your caffeine level up, especially if the company proceeds with its plans to produce a savory version of the chips. Now that would be crunchtastic!

Good, Old-Fashioned Energy Boosters

According to the experts, you don't need performance enhancing drinks, powders, or pills to get a physical and mental edge at work. In fact, such substances may actually be counterproductive. With the right diet and behavior, you can build and maintain energy for peak performance all day. To keep your system in perfect working condition, start by eating a solid breakfast every morning; then avoid obvious dietary pitfalls, snack sensibly, along and indulge in an occasional boost from natural caffeine (as in coffee). The effects may not be as immediate as what you'd get by downing a can of JoltMaster 1000, but they're better for you in the long run.

To say that breakfast is the most important meal of the day is an understatement; it sets the stage for your energy level over the remainder of your waking hours. Dr. Gerard Mullin of Johns Hopkins University says that the best approach is to combine protein--a slow-burning source of energy, such as an egg--with a complex carbohydrate such as a banana or a bowl of oatmeal. And other fruits can't hurt: Dr. Mullin and Cynthia Sass (a nutrition director for prevention) agree that berries are hard to beat--especially the dark ones, which contain powerful antioxidants that Sass calls "little bodyguards that protect healthy cells from aging and free radicals produced by stress, exercise, contaminants in the environment, and so on." Some fruits also contain polyphenols that protect against cancer. For an afternoon power-up, it's wise to stick to fruits or a handful of nuts in lieu of vending-machine candy bars.

And don't worry too much about drinking caffeine. Not only is coffee generally safe, but recent studies have shown that it may have a number of positive side effects, ranging from protecting against Parkinson's disease to lowering heart attack risk. That information isn't a license to abuse coffee, of course. A quattro macchiato will not only spin you out, but download a bunch of calories into your system as well. A better approach is to sip green tea throughout the day; you'll get a mild boost and a dose of antioxidants besides.

Field Guide to Energy Additives

What's lurking in your favorite energy drink? Consult this guide to the common energy-boosting additives to find out what you're assimilating.

B Vitamins
None of the B vitamins bestow energy, but all of them help with biological processes. Though they are numbered (B with a subscript number), you may see them listed by their chemical names: thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folic acid (B9), and cobalamin (B12). Most energy drinks pile on the B's.

Vitamin C
Like the B vitamins, C does nothing for energy, but vitamin C is the O.G. of antioxidants, slaying free radicals (renegade, destructive ions) left and right. As a secondary benefit, it'll keep scurvy away. Arrrr!

Taurine
A major component of bile (yum), taurine may help promote weight loss by regulating insulin levels in the body. The jury remains out on its energy-conferring potential, but just about every energy drink includes it as an ingredient.

L-Carnitine
Remember mitochondria from high school biology? They're the "powerhouses of the cell" that help convert food into energy. And L-carnitine helps them get the job done. It's also an antioxidant.

Caffeine
This stimulant has had a long and healthy relationship with humans. Found in coffee, tea, and (in smaller quantities) chocolate--not to mention in energy drinks--caffeine helps the world wake up and stay awake.

Ginseng
Known primarily as an aphrodisiac, ginseng also seems to have a stimulant effect, most often noticed in the symptom of insomnia. Siberian ginseng, though popular, is not a ginseng at all, as it is not a member of the Panax (ginseng) genus.

Guarana
A South American berry seed, guarana contains about five times the percentage of caffeine that a coffee bean does. Other alkaloids in guarana may increase resistance to stress and increase memory retention, as well as having antioxidant and antibacterial affects.

Gotu Kola
This is not the same thing as kola nut (the flavoring in cola drinks). A medicinal herb that has been in use for thousands of years, gotu kola is said to promote youthfulness and increase mental clarity and memory. These claims have not been confirmed by research.

This story originally appeared on PCWorld