The best energy shots, according to a registered dietitian

• A high-quality energy shot has a healthy amount of caffeine, minimal harmful or artificial ingredients, and tastes well enough that it's not a chore to drink.
• Energy shots are a popular way for people to get a boost of energy via caffeine or an assortment of vitamins, herbs, or stimulants like guarana, taurine, and ginseng.
• Our top pick, the Forto Coffee Shot, is certified organic, doesn't cause significant jitters, and comes in a variety of available flavors.
• This article was medically reviewed by Samantha Cassetty, MS, RD, nutrition and wellness expert with a private practice based in New York City.

In today's fast-paced world, you're expected to be on your game just about every waking moment. If your brain isn't functioning at peak capacity, your productivity suffers, and you may drop the ball in various areas of your life. While rest is important for recharging — and we strongly encourage going easy on yourself — sometimes you don't have the luxury to take a break. That's when a boost from an energy shot comes in handy.

Coffee is by far the most popular energy supplement people tend to consume. But, as you're rushing from one meeting to the next or high-tailing it to the gym, you don't always have time to visit a coffee shop or take a cup from home. Energy shots are a convenient way to get your caffeine fix when you're on-the-go.

This is the main way I use energy shots. I'm used to taking in roughly 125 milligrams (mg) of caffeine three times per day in the form of espresso from my fancy Saeco Xelsis Espresso Machine. But, when I'm away from home, I need to maintain my caffeine intake to stay alert and avoid headaches. It's not the healthiest lifestyle but it works for me. Plus, I closely regulate my caffeine intake to stay below the recommended daily limit of 400 mg.

Caffeine is the most common stimulant in most energy shots. During the testing for this guide, I tried a few alternatives that were advertised as caffeine-free, but they had little to no effect so none made our guide. They mainly serve as a boost of B vitamins, which mostly just end up in your urine.

The shots I tested had between 40 and 300 mg of caffeine along with herbs, nootropics, megadoses of vitamins, and other stimulants, such as guarana, taurine, and ginseng. Since the caffeine levels and other ingredients vary so drastically, it's important to monitor how often you take energy shots and what effect they have on you. It's also smart to consult with your healthcare provider before altering your diet by adding an energy shot to it.

For safety reasons, I tested the energy shots in this guide over the course of several months with a day or two between each test. I also consulted with Mandi Knowles, a registered dietitian with over 15 years of experience, who gave me guidance in what to look for in an energy shot.

Each energy shot featured in this guide went through several tests in order to thoroughly review them across a variety of categories. The most important factors I considered while testing were performance, caffeine content, ingredients, and taste. Here's how each category factored into what made the guide:

• Performance: Each test had to have an element of subjectivity to them and I tried to limit the variables in the tests as much as possible, but there's only so much one can do — especially for something as opinion-based as performance. The closest I could get to reliably reporting on this was to look at how jittery the energy shot made me feel in the first two hours after taking it. I also assessed how task-focused I was five hours after taking the shot, but since this can vary wildly from person to person, it wasn't a major contributing factor.
• Caffeine content: According to Knowles, it's smart to "prioritize the caffeine first and make sure that it has an acceptable dosage to be effective." She recommends between 100 and 300 mg and that "anything higher should be taken with caution as the upper limit is set at 400 mg for adults (and 85 mg for kids.)" She points out that a typical 16-ounce Grande cup of medium roast coffee at Starbucks contains roughly 310 mg of caffeine.
• Ingredients: I looked for shots that had other positive active ingredients outside of caffeine like guarana, ginseng, or taurine. Energy shots are commonly packed full of B vitamins, but Knowles warned against putting too much stock in these. "When it comes to B vitamins, the claim is they usually help the body make energy, but it really comes down to converting food into cellular energy and not a burst of energy." I also looked for shots that rely on natural ingredients and steer clear of artificial sugars or any confusing chemicals.
• Taste: Taste may be the most important subjective test as it's much more relatable than a shot's performance. I rated the taste and aftertaste of each flavor on a 5-point scale. The anchors on my taste scale were: 1 — "wince when drinking it," 3 – "not good or bad," and 5 – "found I craved the flavor." The aftertaste scale anchors were 1 – "need a chaser," 3 – "neutral aftertaste," and 5 – "I crave more." None of the shots received 5s in taste or aftertaste, though there were a few that got close. I found that while most tasted good, several had unpleasant aftertastes.

Additionally, I took into account each shot's nutritional facts, different buying options (e.g., flavors, potency, and package sizes), how convenient the shots are to carry around, and the cost per serving and how much caffeine you get for a dollar spent.

• Best overall: Forto Coffee Shot
• Best eco-friendly: X-Mode Energy Shots on Tap
• Best budget: SToK Caffeinated Unsweetened Black Coffee Shot
• Best nootropic: Tru Focus Shot