Our Stim-Free Pre-Workout Testing Methodology
Pre-workout supplements are one of the most widely used athletic supplements for improving energy, focus and blood flow during workouts. Many pre-workout formulas combine a stimulant with amino acids, nitric oxide boosters, creatine, adaptogens and even thermogenic fat burners.
But what if there was a way to achieve those benefits without the jitters and crashes associated with stimulants? Enter stimulant-free pre-workouts, a growing trend in the fitness world that offers a gentler yet effective alternative.
With so many stim-free pre-workout formulas available, we knew that finding the absolute best ones would involve more than just sorting out the good from the bad. To determine which ones stand above the rest, we developed a custom testing methodology and scoring algorithm.
We score across nine primary categories: cost per serving, sweeteners, energy, hydration, endurance, muscle fatigue reduction, lean muscle support, focus and certifications. Products can also earn bonus credits that boost the overall rating. These categories were developed in collaboration with registered dietitian and doctor of exercise physiology Chris Mohr.
How We Score Stim-Free Pre-Workout Supplements
Our stim-free pre-workout scoring methodology branches off of our broader nutrition product and supplement methodology. We assign each product a score of 1 out of 5 for each of the categories we test in. Those scores are then weighted based on importance and averaged to produce a cumulative score out of 5 for each product, with 1 being the lowest rating and 5 being highest.
Criteria We Evaluate
Cost per serving
Price is an important factor for consumers, and often (though not always) reflects the quality of a product. There are high quality stim-free pre-workout supplements that cost below average, and relatively low quality stim-free pre-workout supplements that cost more than average. Because of this potential discrepancy, this category receives less weight in the overall score.
We rate each stim-free pre-workout based on the price per serving. Here’s the breakdown:
- Less than $1.00 per serving: The highest score is given to the most affordable pre-workout supplements.
- $1.00-$1.49 per serving: This is still a relatively low cost, but edging slightly higher for those who use pre-workout supplements regularly. This range earns an average score.
- $1.50-$1.99 per serving: This range is moving into premium pricing, and may be too expensive for those who use pre-workouts multiple times a week. We give it a low score, but not the lowest.
- More than $2.00 per serving: If price is a barrier, higher than $2.00 per serving is more costly compared to some other options, which could be a challenge for many consumers. For that reason, pre-workout supplements costing $2.00 or more per serving receive the lowest marks.
Sweeteners
Sweeteners may improve the taste profile of a stim-free pre-workout supplement, but they don’t add nutritional value beyond sometimes being a fast-burning energy source. We prefer to see minimal sweeteners in stim-free pre-workout formulas, and we prefer some over others. Here’s how we rate each sweetener:
- Sugar: Added sugar is a refined carbohydrate, and an ingredient most Americans over-consume. The Centers for Disease Control and Prevention (CDC) recommends limiting added sugar to no more than 10 percent of your daily calories. For a daily 2,000-calorie diet, that means no more than 200 calories per day should come from sugar (approximately 12 teaspoons). Based on research from the U.S. Department of Agriculture, adult men consumed an average of 17 teaspoons of sugar per day, and women consumed 15 teaspoons per day from 2017-2018. To avoid health issues like obesity, type 2 diabetes and heart disease, people should limit their added sugar intake. While there often isn't much added sugar in stim-free pre-workout supplements, limiting it as an ingredient is wise, which is why pre-workout formulas with refined sugar receive the lowest score.
- Honey: Honey is a form of added sugar. While it's a different form of added sugar, it’s still sugar, and physiologically there are few differences between the two—none of which have clinical significance. For this reason, we give honey the same low score as sugar.
- Agave: Similar to honey, agave is a form of added sugar with few differences from refined sugar and none that have clinical meaning. It receives the same low score as sugar and honey.
- Maltodextrin: Maltodextrin is a carbohydrate derived from rice, corn, wheat and potato starch. Although it’s not sugar, it acts similarly in the body, so it shares the same low score as all forms of sugar.
- Dextrose: Dextrose is marketed as a high-quality alternative to sugar, but with a glycemic index of 100, it's no different than the other added sugars. It also receives the lowest score in this category.
- Sucralose, Aspartame, Acesulfame: Artificial sweeteners like sucralose, aspartame and acesulfame are non-nutritive, non-caloric sweeteners. They have repeatedly been shown to be safe in the research at moderate amounts. Although a recent WHO report suggested "artificial sweeteners to be possible carcinogens", the dosing that could cause concern is equal to that in approximately nine to 14 cans of diet soft drinks and a much higher dosing than what might be in a stim-free pre-workout supplement. Still, the lack of research on the long term use of artificial sweeteners is the reason we give them a low score, though slightly higher than the score for sugar.
- Erythritol, Xylitol: Erythritol and xylitol are sugar alcohols that provide sweetness with very few calories. We rate them higher than sugar and artificial sweeteners because they contribute to oral health, including reducing plaque, alleviating constipation and triggering secretion of gut hormones that regulate satiety (the feeling of fullness after you eat). One potential downside is that too much of either may cause stomach ache, cramping, gas or even diarrhea, which is why they aren’t given the highest score.
- Stevia: Stevia starts as a plant and is refined and concentrated to create a sweeter end product. Some consumers may be turned off by the sometimes bitter flavor of stevia, but it’s considered safe and is free of calories and sugar. We give it the highest score in this category.
- Monk Fruit: Monk fruit is a non-caloric sweetener that comes from a fruit that's native to China. Its flavor can be less off-putting than stevia, so some appreciate its ability to provide sweetness without the bitter aftertaste. Like stevia, we give it the highest score in this category.
Energy
In non-stimulant formulas, B vitamins and plant extracts are typically used to support the metabolism and improve endurance, still providing a form of energy.
Non-stimulant
- Taurine: Research about the effectiveness of taurine for performance during physical activity is limited and the results are varied. While the data shows promise for taurine to boost performance, the data is mixed and inconclusive at best, which is why we give taurine a lower score in this category.
- Eleuthero Root: There is limited research that shows eleuthero root may improve endurance capacity, but the data is very inconsistent, so we give eleuthero root the me mid-range score as theobromine.
- Vitamins B12 and B6: B vitamins play an important role in metabolism, which is why they are often included in stim-free pre-workout formulas. However, there appears to be no energy boost provided by B vitamins, so they earn the lowest score in this category.
- Niacin: Niacin is an essential B vitamin that may be beneficial for managing triglycerides and cholesterol, but there are no clear benefits for athletic performance. It earns the same low score as vitamins B12 and B6 in this category.
Hydration
Hydration plays an important role in muscle performance and recovery, which is why many stim-free pre-workout formulas include electrolytes. When scoring stim-free pre-workout supplements, we give high scores in this category to formulas that contain these three electrolytes or sources of electrolytes:
- Sodium: Salt is an electrolyte that helps regulate fluid balance in your body and also plays a role in nerve and muscle function.The American College of Sports Medicine (ACSM) suggests consuming 300-600 milligrams of sodium per hour of exercise. If exercising in hot, humid environments or if you're a heavy sweater, more may be needed, so dosing is dependent on a variety of factors.
- Potassium: Potassium is an electrolyte that is also lost in sweat. A dose of 200-500 milligrams may help with hydration when paired with a sodium-rich liquid.
- Coconut Water Powder: Coconut powder is a natural source of potassium, though it’s naturally lower in sodium. It could help with hydration, but those who rely on coconut powder or coconut water as a sports drink may need to consider the addition of sodium.
Endurance
In addition to energy and hydration, pre-workout formulas often contain ingredients intended to boost mental and physical endurance during workouts. Here’s how we score the most common ingredients for endurance.
- Beta Alanine: 4-6 grams of beta alanine has been shown to improve exercise performance by helping regulate acid in muscles, which may prevent fatigue. We give beta alanine the highest score in this category.
- Carnosyn: This is a branded form of beta alanine, so it receives the same high score as beta alanine.
- Ancient Peat and Apple Extract: Data suggests that ancient peat and apple extract may improve endurance by increasing whole-body and blood levels of ATP, which is the energy currency of the body and may boost power and strength in resistance trained athletes. As such, we give them a higher score in this category.
- Rhodiola Rosea: Rhodiola is an adaptogenic herb sometimes included in pre-workout formulas for endurance. There is limited data of inconsistent reliability showing its effectiveness for improving physical performance. Dosing ranges from 200-700 milligrams, which also adds to the uncertainty of its inclusion in pre-workout formulas. While promising, the data are mixed and inconclusive, so we give rhodiola rosea a mid-range score in this category.
- L-Carnitine: L-carnitine plays a crucial role in the production of energy, but adding more to the diet as a supplement doesn't appear to have consistent benefit. It receives a mid-range score because it’s important for energy production, but may not provide a noticeable impact on muscle endurance.
- Eleuthero Root: Limited research shows that eleuthero root may improve endurance capacity, but the data are very inconsistent, so we give eleuthero a mid-range score.
- Astragalus Root Extract: Astragalus root extract is an herb that has been shown in a variety of animal studies to improve exercise performance in animals. However, studies in humans are inconsistent at best, so we give this ingredient a lower score.
- Astragin: Astragin is a branded ingredient derived from astragalus/ginseng that’s marketed to enhance nutrient absorption; however, there is no research showing it to be effective, which is why we give it a lower score.
- Senactiv: Senactive is a branded, proprietary ingredient derived from panax notoginseng and rosa roxburghii. It’s marketed to enhance exercise performance but to date there are no studies on this single proprietary ingredient on exercise outcomes. Because of this, it was given a lower score.
Muscle Fatigue Reduction
This category is similar to endurance, but it focuses on muscular fatigue specifically. We focus on two key ingredients: citrulline malate, which receives the highest score, and beetroot, which earns a slightly lower score.
- Citrulline Malate: In one study, men who supplemented with 6 grams of citrulline malate a day for 15 days experienced a significant reduction in fatigue and an increase in athletic performance in high-intensity anaerobic exercises with short rest times. The same study showed that this dose of citrulline malate might relieve post-exercise muscle soreness. Use of this ingredient may also delay lactic acid accumulation and fatigue.
- Beetroot: Beetroot juice is a rich source of dietary nitrate, which may be used to enhance the availability of nitric oxide (NO) in the body. Using a nitrate supplement may increase NO bioavailability and have the potential to enhance exercise by reducing or delaying fatigue.
Lean muscle support
Pre-workout supplements are commonly used to support muscle growth during strength training, high intensity interval training (HIIT) and cardio exercises. We score stim-free pre-workout formulas in this category based on which active ingredients are included for lean muscle support. Some ingredients are backed by significantly more research showing that they directly support the growth of lean muscle. These ingredients carry high scores in this category. Other ingredients lack research or research has inconclusive results about whether the ingredient is effective for supporting muscle growth. These ingredients are scored lower.
Here are the 11 ingredients we factor into a stim-free pre-workout formula’s score in this category:
- Creatine: Creatine is the most well researched and effective dietary supplement to date, with data suggesting that it contributes to improvements in recovery, lean mass, strength and more.
- Betaine: Some research has shown that 1-2 grams of betaine may help with strength and mass gains, potentially by enhancing the anabolic profile, signaling pathways that communicate to our bodies what they need to grow and ultimately protein synthesis.
- Leucine: Leucine is the most important of the three branched chain amino acids for muscle growth. However, leucine seems to be more effective when part of the whole protein itself versus consuming it as an individual amino acid.
- Taurine: There are limited and varied findings in research about the effect of taurine on physical performance, so we score it lower than creatine, betaine and leucine.
- Isoleucine: Isoleucine is one of the three branched chain amino acids and an isomer (molecule) of the amino acid leucine. Similar to leucine, isoleucine seems to be more effective when part of the whole protein versus consuming it on its own.
- Valine: Valine is one of the three branched chain amino acids. While some data suggest that valine is beneficial to exercise and performance, the majority of the data indicates that individual amino acids don’t provide any benefit when a person is already eating enough protein.
- Zinc: Zinc is one of the most critical minerals in the human body. Some, but not all, research suggests athletes may have additional zinc requirements, but adding this mineral to a diet with sufficient zinc intake doesn’t enhance performance in any way.
- Vitamin D: Vitamin D is an often under consumed vitamin, but not a critical component of a pre-workout formula.
- BCAA: Branch chain amino acids (leucine, isoleucine and valine) have been used extensively by athletes, but data on their use and benefit is inconsistent, and with adequate protein, appears mostly useless.
- Boron: Boron is an essential trace mineral with very early data suggesting it may boost testosterone. However, these data were published nearly 40 years ago, and only shown in postmenopausal women.
- Calcium: Calcium is an essential mineral, but its use in pre-workout formulas is not beneficial for exercise performance.
Focus
Ingredients for focus can be an undervalued benefit of pre-workout formulas, but when properly dosed, they can add to the intensity and intentionality of your workout. Many of the ingredients included in pre-workout formulas need more research to confirm their effectiveness, so evidence-backed ingredients earn a higher score in this category, while ingredients with little or no supporting evidence receive lower scores.
- L-theanine: L-theanine is an amino acid found in tea leaves, and has been studied most extensively in combination with caffeine to measure cognition. Data show promise for the combination of L-theanine and caffeine, suggesting it may be useful in a pre-workout product for improving focus with fewer of the side effects of caffeine.
- Alpha GPC: Alpha GPC is a natural chemical and nootropic often used for its purported benefits for cognition. The research supporting its benefits with athletics is lacking; however one small study found that the seven male participants who supplemented with 600 milligrams of Alpha GPC 45 minutes prior to simulated bench throws had a greater exercise-induced growth hormone increase and 14 percent improved power output.
- Tyrosine: Tyrosine is an amino acid that has been suggested to enhance performance. Few studies have examined this possibility, but one that did (published nearly 20 years ago) found no benefit in terms of exercise performance.
- Huperzine A: Huperzine A is an alkaloid naturally occurring in toothed clubmoss. It may inhibit the enzyme that breaks down acetylcholine (which could play a role in muscle contractions), hence the theory that huperzine A may be of benefit to athletes and those using pre-workouts for exercise. However, a recent study suggests its use should be reconsidered because of the lack of a connection between huperzine A and improved exercise performance.
- Choline Bitartrate: Some pre-workout formulas contain choline bitartrate, an organic compound, because it's been reported that plasma levels of choline deplete during physical exertion. However, no significant effects were seen with choline supplementation on any outcome performance measure in more than one study.
Certifications
The Food & Drug Administration (FDA) doesn’t regulate dietary supplements before they’re released to the market (though they do regulate ingredients and finished products), so it’s important to look for products that have certifications for purity and potency from third-party testing labs. These testing certifications show whether a dietary supplement contains what the brand says it contains in the doses advertised (potency). It also tests for harmful toxins (i.e. mold, heavy metals, etc.), and some check for banned substances (purity).
Nearly all reputable supplement companies test their products in-house for safety and label accuracy, but many brands also make the decision to have their products tested by a third party for even further quality and safety assurance. That’s why we've chosen to give brands who take on this additional responsibility bonus credits.
Smaller, newer supplement companies often can’t afford testing or certifications from high profile third-party testing labs—regardless of the purity or potency of their products—which is why certifications are weighted lower than other categories in our algorithm.
The certifications we look for include:
- Informed Choice (ICFS): Informed Choice offers several certifications, the most recognizable of which being the Informed Sport badge. This certification is critical for athletes who might get drug tested for their sport.
- NSF: NSF is an independent testing organization founded in 1944.
- U.S. Pharmacopeia (USP): USP is an independent, non-profit scientific organization that tests medicines and supplements, founded over 200 years ago.
- USDA Certified Organic: This certification by the United States Department of Agriculture indicates that the product contains 95 percent or more organic ingredients.
Bonus credits
Since the supplement industry—especially pre-workout supplements—is constantly evolving, we pay attention to products and brands that are going above and beyond to stand out. That’s why we incorporate bonus credits into our pre-workout supplement scores to recognize innovation and encourage healthy competition among all brands. All bonus points are equally weighted and cumulatively provide a small boost to the product’s overall score.
Pre-workout formulas are awarded bonus credits for:
- Sustainable Packaging: An ongoing commitment to sustainability. Any company that offers sustainable packaging gets bonus credits because less plastic tubs end up in landfills.
- Antioxidants: With adequate dosing, antioxidants may improve exercise performance.
- Organic Ingredients: Some consumers may feel more comfortable with organic (or mostly organic) products.
- Non-GMO Ingredients: Similarly, some consumers may feel more comfortable with products containing no genetically modified ingredients.
- All-Natural Ingredients: Some consumers may also feel more comfortable with all-natural products.
- No Proprietary Blends: Transparent labels enable consumers to see whether or not the key ingredients are included in clinically meaningful doses.
Summary
There are countless stim-free pre-workout formulas available for consumers, and our job is to determine which products stand above the rest in terms of quality, potency, effectiveness and value. Our stim-free pre-workout testing methodology involves scoring products across nine categories chosen in partnership with nutrition experts. The final weighted score supports our decision to either include or exclude individual products in our “best of” roundups.
For more information on our nutrition and supplement testing philosophy, please refer to Our Nutrition Products and Supplements Methodology page.