Best Amino Acid Supplements: Top 5 of 2024

You don't have to be a bodybuilder or an athlete to benefit from essential amino acid (EAA) or branched-chain amino acid (BCAA) supplementation. Amino acids are the building blocks of protein, providing your body with the means for cell growth and repair and contributing to overall health. This fast-growing market is estimated to value almost $50 billion globally by 2030.

These supplements are generally taken around workouts to help your body build muscle and improve athletic performance. They can also boost your endurance and reduce post-workout soreness and fatigue.1

All amino acid supplements are not created equally, however. This guide breaks down our top five picks for best amino acid supplements in 2024 based on their effectiveness, cost, safety, and customer satisfaction.

If you don't have time to read our complete guide, glance over our top picks below.

At Innerbody Research, we extensively test each health service or product we review, including amino acid supplements. We’ve used these products before, during, and after workouts to see if any or all of them had any effect on our experience. We critically assess the entire ordering process to save you from any surprises and prepare you for each company’s customer service standards and logistical quality.

In addition to actually trying these products for ourselves, our team pored over hundreds of scientific publications regarding amino acids, exercise performance, and muscle building. More than 1,000 hours of concerted research went into making this page as helpful as possible.

Additionally, like all health-related content on this website, this review was thoroughly vetted by one or more members of our Medical Review Board for accuracy. We’ll continue monitoring the landscape to try new amino acid supplements that come along and keep this article current.

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions involving staying healthy and living healthier lifestyles.

One person's needs from an amino acid supplement may be different from another’s, but there are still undeniable objective criteria we use to evaluate the potential of these supplements. Those objective criteria include efficacy and safety — determined by their ingredients and doses — as well as cost. We also applied subjective criteria like taste and customer service experience to round out our rankings.

Efficacy and safety held the most sway in our product rankings. And since we actually tried these products, we can speak to which ones taste the best, which is going to be a sticking point for many. Cost was less of a factor, considering the relatively similar prices you find among groups of flavored or unflavored EAAs. And while our customer service experiences are worth noting, they only partially influenced our considerations; we’ve ordered many, many products, and the fact is that you may end up having a more positive or negative shipping experience based on supply chain issues, your expectations, or simply your luck of the draw.

Let’s take a closer look at each criterion in more detail to better understand how we came to our conclusions.

Effectiveness

Winner: Naked Nutrition EAAs

The effectiveness of a given amino acid supplement will depend in part on what you want to get from it. If you’re just looking for a little boost in energy and overall health, a supplement with a lower dose of amino acids might suit you. But if you’re looking to build muscle or increase exercise performance in general, you’ll want something more robust. And since so many of these supplements are powders that you mix into a liquid, getting a stronger product is typically smart; you can easily cut a dose in half if the serving is larger than you want.

Of course, strength isn’t the only issue here. Balance is also key. An amino acid supplement that doesn’t contain all nine essential amino acids will have a more specific function than a balanced product containing every one of them. Studies show that, in terms of muscle protein turnover, if any of the nine essential amino acids are absent during absorption, muscle protein synthesis will likely fail to overtake the rate of protein breakdown.6 That’s not to say a supplement like Transparent Labs BCAA Glutamine will be ineffective. It just means that its efficacy is more limited, forcing you to consider supplement timing and meals that can provide additional amino acids.

To that end, we found Naked Nutrition’s EAAs to offer the most potential for efficacy across a variety of needs. It contains just over 9g per serving of nine essential amino acids in good balance, with a 2:1:1 ratio of the three BCAAs and higher doses of the other six amino acids than many competitors’ products. And since each bottle contains 50 servings at a very reasonable price, anyone hoping to build muscle better through supplementation can easily take a double dose or more so long as they clear it with a doctor first.

Safety

Winner: Transparent Labs BCAA Glutamine

Safety is an important consideration when buying any dietary supplement, in large part because the Food and Drug Administration (FDA) regulates these products differently than conventional foods and drugs. When considering safety among amino acid supplements, we looked at the following factors:

• Manufacturing methods
• Ingredient transparency
• Food allergens
• Fillers and additives
• Third-party testing

Transparent Labs BCAA Glutamine is the winner in this category based on its clear labeling of ingredient amounts and its inclusion of high-quality fermented BCAAs and glutamine. You’ll even see doses in the “other ingredients” section, where almost every other company in the U.S. lists the ingredients but not the doses of things like citric acid, silicon dioxide, or natural flavor.

Transparent Labs also utilizes a third party to perform testing that looks for potential contaminants like mercury or E. Coli. The site also lists certificates of analysis you can check against the lot number printed on your product, though sometimes the publication of these certificates lags behind product sales. The lot to which our BCAA Glutamine belonged was one number higher than the latest published data. That means you might have to check back if you’re genuinely interested in the results of Transparent Labs’ third-party testing, but the effort remains steady, and we believe it speaks to the product’s overall safety.

Taste

Winner: Type Zero Clean Amino Burn

One of the advantages of actually trying these products for ourselves is that we can give you a real-world account of their taste. This is a subjective measure, and not everyone will share the opinions of a few product testers, but if you're concerned about flavor — and trust us, you should be — you'd be wise to consider our findings.

Despite being our top overall pick, taste is where Naked Nutrition EAAs doesn't shine. It's not a knock on the company or the product, though; that's an unflavored amino acid supplement, and no unflavored amino acid supplements taste good on their own. Some liquids are better suited to concealing the taste of an unflavored amino acid. To name a couple that we'd recommend, consider smoothies (with a lot of tart, acidic ingredients) and bone broths.

Our team put together ratings for how each of our top five amino acid supplements tasted, as well as how well they each mixed into a liquid. For taste and mixture assessments, we used 11 ounces of cold water with plain crackers as palate cleansers.

Here are our results:

As you can see, nothing came close to Type Zero for taste. This is partly because it uses erythritol and stevia for sweetness, rather than stevia alone (Transparent Labs) or sucralose (RULE1). Of course, recent research has associated erythritol with a heightened risk of major adverse cardiovascular events (MACE), and it’s gotten a lot of attention in the news. The study is compelling, and it highlights the need for further research to ensure the ingredient’s safety; it does not establish causality between erythritol and MACE.

Type Zero’s product didn’t mix in quite as well as the unflavored version did — which left almost no discernable presence in clear water. There is a little clumping and settling with all of the flavored products if you use a fork to stir the mixtures together. In a plastic mixing cup with a mixing ball inside or in a blender, any of these powders will mix well.

Cost

Winner: Bulk Supplements EAAs

At first glance, the cost of many amino acid supplements seems pretty similar, with prices typically ranging between $25 and $40. But there are a few variables you might not initially consider that can render one purchase more economical than the next. For example, both Transparent Labs BCAA Glutamine and Naked Nutrition EAAs bear a $40 price tag. Both companies also offer 10% off that price when you subscribe. But Naked Nutrition’s EAA bottle contains 50 servings compared to the 30 you get from Transparent Labs. And Naked Nutrition also takes an extra 10% off your first shipment, bringing down the cost of your initial investment.

However, no one seems able to compete with the prices of Bulk Supplements. This company also has a package containing 50 servings, but it costs about $16 less than Naked Nutrition’s. What you ultimately sacrifice in the deal is the ability to know exactly what you’re getting with each dose, as Bulk Supplements conceals its ingredient-specific dosages behind a proprietary blend. It’s not a bad gamble to take if budget is your primary concern, and you can take an additional 5% off of your purchase price using discount code INNERBODY5.

Bulk Supplements also has the lowest threshold at which you receive free shipping, but it has some of the highest shipping fees if you don’t reach that point. It’s not typically enough to offset the savings you find on the products themselves, but it's worth noting.

Customer service

Winner: Naked Nutrition

Customer service and satisfaction are essential considerations when buying dietary supplements because not everything works for everyone. We look for things like ease of contact, efficiency of communication, good return policies, and reasonable shipping times to make this determination.

None of these companies offer a money-back guarantee. Each has its own specific return policy, all of which require that the product is still unopened. The longest of these windows (30 days) is shared by Transparent Labs, Type Zero, and Bulk Supplements. RULE1 and Naked each give you about two weeks.

Despite not having the best return policy, we still gave the win for customer service to Naked Nutrition thanks to a few factors.

We want to give an honorable mention to RULE1 here, as well. In addition to having shipping speeds that matched Naked’s, the company included 11 free samples in its packaging, along with a pair of stickers and a rubber RULE1 bracelet. The samples included protein powders, BCAAs, mass gainers, and a weight management blend.

The chart below offers a quick glimpse into how our top-rated amino acid supplements compare. These price comparisons do not account for subscription plans or bulk purchases, which can often earn significant savings. Also, note that the cost per month is based on one daily serving of a given product’s serving size. Some containers come with around 50 servings, so the monthly cost will be a lower number than the actual price of the container.

Amino acids are molecules commonly referred to as the building blocks of protein.2 Often, this brings to mind muscle-building, as protein is typically associated with strength training.3 But the body uses amino acids to form proteins essential for numerous bodily functions, including:

• Developing cells
• Repairing body tissues
• Digesting food
• Creating neurotransmitters and hormones
• Promoting energy
• Boosting immunity
• Maintaining healthy hair, skin, and nails

There are three types of amino acids with respect to the human body, which we’ll discuss in-depth below. They are:

• Essential amino acids (with BCAAs as an important subgroup)
• Nonessential amino acids
• Conditionally essential amino acids

Essential amino acids

Essential amino acids are those we have to attain from dietary and supplement sources because our bodies can’t produce them. Naturally, these are the kind that amino acid supplements focus on contributing. There are nine essential amino acids, including:

We can naturally derive essential amino acids from protein-rich food sources. You’ll find essential amino acids in:

Complete proteins (like the first eight items on the list above) contain all nine essential amino acids. On the other hand, incomplete proteins have some — but not all — essential amino acids.

Contrary to popular belief, vegetarians and vegans can easily get all of their essential amino acids from plant-based sources, albeit in lower concentrations than what meats contain. Amino acid supplementation can help ensure those with restricted diets still get all the protein-making compounds they need for optimal health.

BCAAs

While not formally a separate kind of amino acid, many over-the-counter amino acid supplements focus on BCAAs or branched-chain amino acids. These consist of three essential amino acids:

• Leucine
• Isoleucine
• Valine

You’ll usually see these three amino acids in a 2:1:1 ratio (e.g., 1,000mg leucine, 500mg isoleucine, and 500mg valine).

BCAAs are popular among bodybuilders and athletes because they’ve been shown to support muscle growth and tissue regeneration and have also demonstrated the ability to reduce delayed onset muscle soreness (DOMS) in clinical trials.4 Of course, muscle protein synthesis is a complex process that is in constant battle with muscle protein breakdown. BCAAs alone may not be sufficient to elevate protein synthesis to a rate high enough to overtake protein breakdown in the absence of the other essential amino acids. BCAA supplements can still play an important role in fitness and strength training, but you may need to time their use more strategically, which we’ll discuss below in our section on muscle protein synthesis.

Nonessential amino acids

Nonessential amino acids are still critical for health and wellness, but our bodies can produce enough of them independent of dietary sources. The nonessential amino acids are:

• Alanine
• Arginine
• Asparagine
• Aspartic acid
• Cystine
• Glutamic acid
• Glutamine
• Glycine
• Ornithine
• Proline
• Serine
• Tyrosine

These amino acids are mostly made from glucose and support tissue growth, immune function, red blood cell creation, and hormonal regulation, among other tasks. It’s rare to see any of these amino acids in amino acids supplements, which typically concentrate on essential amino acids. But glutamine makes an appearance in two of our top five supplements (Transparent Labs and Type Zero). Of the 11 traditional nonessential amino acids (which exclude citrulline and ornithine), glutamine is among the most thoroughly researched for several impressive benefits, including cognitive support and an ability to maintain and even repair intestinal linings.5

Conditionally essential amino acids

Significant stress or illness can cause our bodies to produce too few nonessential amino acids, which can result in numerous complications, especially around invasive surgeries. These nonessential amino acids then become “conditionally essential,” and they can include:14

• Arginine
• Cysteine
• Glutamine
• Tyrosine
• Glycine
• Ornithine
• Proline
• Serine

Since these conditional amino acids are still important to keep our body functioning, it’s crucial to ensure that we maintain healthy levels of them. Unfortunately, few amino acid supplements include them, with the notable exception of glutamine. You’ll also find arginine in Type Zero’s Clean Amino Burn. If you’re going into surgery any time soon, be sure to talk with your doctor about supplementing for specific conditionally essential amino acids.

Amino acid supplements are designed to either ensure your body has sufficient essential amino acids to maintain its health or that it has enough amino acids to improve certain health parameters, including muscle growth and maintenance.

Amino acid sources mostly contain some or all of the essential amino acids. When you consume these (either in supplement form or in your daily meals), your body puts them to work for various tasks, from cognition to immunity. One of those tasks is muscle protein synthesis, a process that deserves significant attention, considering the interest in amino acid supplements among athletes and weightlifters.

How amino acids influence muscle protein synthesis

If you consume around 1,800 calories per day, and around 20% of those come from protein (the typical American diet), you could spend a few hours pumping iron in the gym without seeing many results. You may trick yourself into thinking you’re at least “toning” your muscles, but that’s not a real thing. People think they’re getting toned because they’re burning fat through strength training and revealing the shapes of the muscles they already had. Building muscle is a more complex process that requires a somewhat strict management of both calories and proteins.

At every moment of every day, your body is engaged in muscle protein turnover.6 It breaks down muscle tissue to create nonessential amino acids and supply other cells with energy. But it’s also constantly building new muscle tissue with essential amino acids you get from your diet. This turnover is never perfectly balanced. Immediately after a protein-rich meal, muscle protein synthesis occurs at a higher rate than breakdown. Strength training has also been shown to instigate this particular balance, which we often refer to as the anabolic state.

Once your body is done absorbing those new amino acids, the balance shifts in favor of muscle protein breakdown. This shift typically takes a few hours. You’ve entered the “catabolic state” when your body’s muscle protein breakdown occurs at a greater rate than protein synthesis. One of the reasons that bodybuilders and Hollywood superhero actors have to eat small, protein-rich meals every couple of hours is to avoid the catabolic state and maximize muscle protein synthesis.

But no one on our testing team has a personal chef or a major movie studio paying us millions of dollars to do nothing but get in shape (yet), and maybe you don’t either. And this is where amino acid supplements come in.

How and when to take an amino acid supplement

Since one person’s goals with an amino acid supplement may be different from another’s, it’s hard to prescribe one dosage or regimen over another. But let’s focus on exercise performance and strength training for a moment.

You may notice that you don’t get the same amount of each amino acid in a supplement. BCAAs usually make up the largest portion of a given dose. This is true in amino acid supplements designed for exercise performance and general health alike. That’s mainly because studies have shown BCAAs to be among the most important amino acids for protein synthesis in general and muscle protein synthesis in particular. But equally relevant studies have shown that in the absence of the other six essential amino acids, BCAAs might not be enough to instigate protein synthesis on their own.3 That’s why complete proteins are so important.

Leucine, the BCAA that appears in twice the concentration of the other two BCAAs in most supplements, tends to get the party started by activating the mechanistic target of the rapamycin (mTOR) pathway.7 This pathway runs throughout the body and regulates everything from gene transcription to cellular apoptosis. It’s also a major regulator of growth via muscle protein synthesis. You can loosely think of it as the switch that turns muscle protein synthesis on, and you can imagine leucine is the hand that flips the switch.

Once that pathway is active, protein synthesis depends on all nine essential amino acids to maintain an anabolic state and actively build new muscle tissue. This not only builds muscle in the vicinity of strength training, but it can also prevent muscle loss from catabolism during and after intense cardiovascular workouts.6

Taking all of this information into account — the specific role amino acids play in regulating anabolic and catabolic states, their active times in the body during nutrient absorption, and the typical dietary habits of most Americans — we believe the ideal time to take an amino acid supplement is immediately before, during, or after a workout. If you’re someone who likes to eat a big meal right after working out, you’ll want to take your supplement before you exercise. If not, or if you tend to lose steam in the middle of a workout, it would be wise to take your supplement immediately prior to or during your workout (and to take one that contains some added electrolytes).

The only time we’d recommend an amino acid supplement immediately after a workout is if you don’t intend to consume much food for at least an hour afterward, and especially if fat loss is a primary fitness goal for you. Amino acid supplements contain very few calories compared to food sources or protein drinks, so you can use them to prevent muscle protein breakdown for a couple of hours after an intense workout while successfully managing your caloric intake to help burn fat.

If you’re more interested in a BCAA supplement than an EAA supplement, we’d recommend using it alongside a protein-rich meal to ensure you’re getting some of the most important essential amino acids (especially for meals that contain many incomplete proteins). You could also use a BCAA-laden pre-workout mix before hitting the gym, more as a way to stave off muscle loss for intense cardio than as a way to increase muscle building.

Amino acid supplements, particularly BCAA supplements, have appealed to athletes and bodybuilders for years, and they can be an excellent component of a fitness plan. But some research indicates that essential amino acids may improve other health parameters, as well, including blood glucose management, immunity, and the inhibition of tumor growth.8 The potential for these benefits requires further study, but it’s promising that some of the research at this point has been so positive.

For otherwise healthy individuals, there isn’t much risk involved in amino acid supplementation, so anyone trying to lose fat, build muscle, or just maintain their health could benefit from it.

Who shouldn’t use amino acid supplements?

Unfortunately, some of the positive potential we see in amino acid studies implies other dangers. For example, because amino acid supplements can impact blood glucose levels, they may interfere with diabetes or thyroid medications. Some research even indicates that amino acid supplementation may be associated with a higher risk of developing type 2 diabetes.15 If you're taking any ongoing medications or have a chronic medical condition, you should consult your doctor before beginning any new dietary supplement.

You also might not need a supplement if you already get sufficient dietary essential amino acids. And if you’ve found an economical and time-efficient way to eat like a bodybuilder every couple of hours, you likely get plenty of amino acids that way.

If your interest in amino acid supplements comes from a long-term inability to gain muscle after intense strength training, there may be other factors at play. Your amino acid intake can be well above sufficient for muscle growth in healthy individuals, but you may have low testosterone or a more severe condition that you’d want to address directly.

Amino acid supplements are inappropriate for children under 18 and pregnant or lactating individuals.

Amino acid supplements are generally safe for non-pregnant, non-lactating adults. They produce few side effects, but those that can occur include:

• Headaches
• Diarrhea
• Nausea
• Flushing

Because amino acid supplements impact blood glucose levels, it’s essential to talk to your doctor before use if you take diabetes medications or have any chronic medical condition.15

And while this isn’t necessarily a safety concern, you should always investigate the source of your amino acids. BCAAs, in particular, have been sourced from things like human hair in recent years. These are typically supplements that come from unscrupulous sources, often selling their products for suspiciously low prices. For the most part, if a product is labeled as vegan or fermented, it most likely comes from corn, soy, or another vegetable source.

Of course, that leads to an allergy consideration. Those with soy or nut allergies should be careful when selecting an amino acid supplement. To that end, Naked Nutrition is among the finest sources of allergen-free supplements, and its EAAs are certified vegan, non-GMO, and free of gluten, soy, and dairy.

Some amino acid supplements contain erythritol, which has been in the news recently due to a prominent study linking it with a higher risk of cardiovascular events such as stroke.16 The study was large enough to be statistically significant, and the media have done a great job turning the findings into a doomsday notice for anyone who’s ever ingested the ingredient. But there were several shortcomings in the study that limit the applicability of its findings.

For starters, the study population was almost entirely over 60 and already at risk for cardiovascular events. Many had obesity or diabetes, and no consideration was given to race, ethnicity, socioeconomic status, or habits such as smoking or alcohol consumption. This isn’t to discredit the study by any means, but it should calm fears of erythritol somewhat. It may be wise to avoid products containing large amounts of erythritol if you’re over 60, have high blood pressure or another cardiovascular risk factor, or have a history of cardiovascular disease and stroke in your family. This would be out of an abundance of caution at this point, and we’ll update our considerations as more data comes in.

Best overall and cleanest ingredient profile

Naked Nutrition is a company dedicated to transparency, providing its ingredients without fillers, added flavors, or proprietary blends. In Naked EAAs, you get a vegan powder with three potent branched-chain amino acids in effective doses. The other six essential amino acids are present in higher doses than we’ve seen in most comparable supplements. There are only ten ingredients present: nine essential amino acids and sunflower lecithin.

Here’s the complete list:

• Leucine: 2,400mg
• Isoleucine: 1,200mg
• Valine: 1,200mg
• Lysine: 1,200mg
• Threonine: 1,200mg
• Methionine: 900mg
• Phenylalanine: 450mg
• Histidine: 450mg
• Tryptophan: 250mg

Of the three amino acid supplements on our list that offer all nine essential amino acids, these are the highest quantities of non-BCAA amino acids we could verify, and the BCAAs are dosed only a hair below those in RULE1’s Essential Amino 9, which has 5g of BCAAs to Naked’s 4.8g.

Taste and mixability

In testing, Naked Nutrition’s EAAs had the highest score for mixability in the group, but it also had the lowest score for taste. To be fair, none of our testers have ever found an unflavored amino acid supplement to be palatable. Without flavoring, this kind of supplement typically tastes the way burnt hair smells, though somehow also more bitter than that. The taste lingers, too. In our initial testing setup, we didn’t think we’d need a palate cleanser, but we started with Naked’s EAAs and immediately realized it would be unfair to the next supplement in the lineup for us not to provide crackers to testers between products.

On the mixing side, Naked’s EAAs all but disappeared into 11 ounces of cold water when stirred in a glass with a fork. There was no clumping and almost no clouding whatsoever. This is good news; if it mixes that well into cold water, it will mix easily into just about anything else. And you won’t want to mix an unflavored amino acid supplement into plain water. You’ll be mixing it into something with flavor — like a tart juice or a smoothie, for instance, or savory bone broth — and you won’t need to worry about the flavor of the supplement by itself.

Pricing

Each 1.1lb tub contains 50 servings, making Naked’s daily serving less than half the cost of most other brands. It’s still a little more expensive than Bulk Supplements’ EAA Powder, though. You can earn additional savings by enrolling in Naked Nutrition's subscription program, which takes 20% off your first shipment and 10% off subsequent shipments.

Naked Nutrition provides free U.S. shipping on all orders over $99. For orders under $99, shipping starts at $7.00. The company also has a loyalty rewards program for frequent customers that builds up points you can redeem against future purchases. You can earn points by taking the following actions:

A single container of Naked Nutrition EAAs would require 3,500 points to get for free. If you do all of these things that are worth bonus points (including celebrating a birthday), you’d still have to spend $825 on additional products. If all you ever get from Naked is the EAAs on a subscription basis, you’d have to buy around 23 containers just to earn one for free. There are two additional tiers to Naked’s rewards program, and spending $750 within a year bumps you up to a tier in which the money you spend is with five points per dollar instead of three. Ultimately, it makes too small a difference between $750 and $825 to even do the math.

The only other company we review here that has a loyalty program is RULE1, and it requires you to spend a lot less to get a free bottle of its amino acid supplement.

Best for gut health

Transparent Labs BCAA Glutamine is a workout and recovery supplement containing three branched-chain amino acids with vitamin C, glutamine, and coconut water powder. It’s gluten-free and non-GMO, and it contains no artificial preservatives, coloring, or sweeteners. We chose Transparent Labs BCAA Glutamine as our best option for gut health primarily thanks to its 5g dose of glutamine. That also makes it a wise choice for those concerned with immunity.9

Numerous studies have implicated glutamine as a key player in gut health, particularly as it pertains to tight endothelial junctions, which are typically compromised in leaky gut syndrome, a disorder only recently gaining recognition in the medical community.10 There is also somewhat substantial evidence that vitamin C can positively influence the balance of gut bacteria.11

Transparent Labs BCAA’s full ingredient list includes:

• Leucine: 4,000mg
• Isoleucine: 2,000mg
• Valine: 2,000mg
• Glutamine: 5,000mg
• Coconut water powder: 1,000mg
• Vitamin C (ascorbic acid): 1,500mg

Transparent Labs BCAA Glutamine is the only supplement in this guide and one of the few supplement companies we’ve reviewed in any health sphere to include doses for its inactive ingredients. The quantities are listed on the labels of the containers we received, but they aren’t listed on the website’s label images. Here’s that list:

• Citric acid: 1,500mg
• Natural flavor: 1,150mg
• Stevia: 515mg
• Calcium silicate: 257.5mg
• Silicon dioxide: 257.5mg

Only a few people for whom these measurements will matter, but it speaks to the company's dedication to transparency that it would include them with such specifics.

Taste and mixability

BCAA Glutamine didn’t mix into water quite as well as the unflavored options on our list, but it also didn’t suffer from any clumping as others did. It mixed in cleanly, filling the water with a dense pink color appropriate to its flavor (we tried the tropical punch). The flavor was middling. It was sweet enough, thanks to the stevia. But without erythritol to combat stevia’s natural bitterness, there was something of an unpleasant aftertaste to it. Ultimately, neither its taste nor its mixability would be a reason to avoid it, though they shouldn’t be the main reasons you buy it.

Available flavors include:

• Sour Green Apple
• Tropical Punch
• Strawberry Lemonade
• Blue Raspberry

Pricing

Transparent Labs currently offers BCAA Glutamine as a one-time purchase or on a subscription basis. In addition to offering 10% off, a subscription unlocks free shipping that would otherwise only be available on orders over $149.

Here’s what the pricing looks like:

Buying from the company website ensures a 60-day customer satisfaction guarantee, and all orders over $99 include free shipping in the U.S. Shipping for orders under $99 starts at $7.99.

Best tasting

Despite being a relatively young company, Type Zero offers a handful of powders and capsules aimed at physical and mental fitness. That catalog includes three amino acid supplements:

• Clean Amino Burn
• Vegan BCAAs + Electrolytes
• L- Glutamine

Clean Amino Burn contains the most amino acids of these three options, with all three BCAAs, arginine, glutamine, citrulline, tyrosine, and phenylalanine present. While glutamine has been shown to aid in everything from exercise performance to gut health, the inclusion of arginine is interesting here. Arginine is typically used as a nitric oxide booster aimed at increasing blood flow to improve workouts. It’s also frequently found in male enhancement supplements for its purported ability to bolster erectile performance, though this claim requires more evidence.

Type Zero’s Clean Amino Burn is the only supplement in our guide to contain caffeine, which can add some extra energy to your workouts. However, if you’re someone who works out at night, it might keep you up later than you’d like. Type Zero offers a stim-free pre-workout, but it’s a very different formula, and it only contains the amino acids arginine, citrulline, and tyrosine.

Type Zero used to conceal its ingredient quantities behind proprietary blends, but the company has since decided to list each ingredient quantity individually, and we’re pleased by this course correction. Previously, there were three blends: the Vegan BCAA Complex, the Weight Management Complex, and the Electrolyte Complex. Now, the ingredients are ordered only by their quantities.

Even when the company had its ingredient quantities concealed, we could still see the ingredients themselves, and it appears as though that profile has changed. Gone is the dose of coconut water powder from the electrolyte blend, but new to the mix is a 15mg dose of evodiamine, an alkaloid compound with noted effects against obesity, pain, and cognitive decline.17

Here’s the full, updated ingredients list for Type Zero’s Clean Amino Burn:

Taste and mixability

Our testing team’s preference for Type Zero on the basis of taste was unanimous. We tried the peach mango, and after tasting Naked Nutrition’s unflavored EAAs, we had pretty low expectations for the category. But this was the one supplement of the entire lot that our testers looked forward to tasting on their own in the future. The only significant downside to Type Zero’s flavors is that many of them go in and out of stock too frequently.

Available flavors include:

• Peach Mango
• Piña Colada
• Watermelon Rush
• Fruit Punch

Clean Amino Burn wasn’t our highest-rated option in terms of mixability, but it did almost completely dissolve, leaving only a few small clumps stuck to the bottom of a glass. Preparing the powder with water in a shaker cup, rather than stirring it in a glass as we did, would likely eliminate all such clumps.

Pricing

Type Zero’s pricing is pretty straightforward, mostly due to the company’s lack of subscription or bulk savings opportunities. Here’s a look at how the company’s three amino acid-based supplements are priced:

The glutamine supplement also comes as a two-pack, which is the closest Type Zero gets to bulk discounts. It brings the cost of each container down to about $30.

Shipping from Type Zero used to cost a flat $5 on all orders, but the company has since instituted a $35 free shipping threshold. That’s the lowest free shipping threshold among the companies in our guide by $24. And if you don’t meet the threshold, Type Zero’s $5 charge is still the lowest shipping charge in this guide.

Best pre-workout

Other than Naked Nutrition’s EAAs, RULE1 Essential Amino 9 is the only product in our guide with verifiable quantities of all nine essential amino acids. Its BCAA dose is slightly higher than what you’ll find from Naked Nutrition, but the doses of its other six amino acids are noticeably smaller.

RULE1 includes 500mg of electrolytes in its formula, which is one of the aspects that earned it our best pre-workout title. Type Zero’s Clean Amino Burn actually provides double that quantity, but its inclusion of caffeine makes it unsuitable for nighttime exercise, whereas RULE1 can accompany workouts at any time of day or night. And since RULE1 also has a complete protein profile, it easily makes sense as a top pre-workout option.

Here’s a look at the ingredients:

• Leucine: 2,500mg
• Isoleucine: 1,250mg
• Valine: 1,250mg
• Lysine: 900mg
• Threonine: 850mg
• Phenylalanine: 450mg
• Methionine: 150mg
• Histidine: 100mg
• Tryptophan: 50mg

RULE1’s 500mg electrolyte blend includes:

• Sodium chloride
• Potassium chloride
• Magnesium oxide

Of course, you may still want that extra pep from caffeine, which is why RULE1 makes an alternative Essential Amino 9 + Energy — an identical formula but for the addition of 130mg caffeine from tea leaf extracts.

One possible sticking point with RULE1 is that it makes no claim that its BCAAs are suitable for vegans or vegetarians, which led us to believe they weren't. We reached out to the company and discovered that it sometimes uses vegan ingredients (typically fermented corn) and sometimes not. When it uses non-vegan ingredient sources, its BCAAs come from poultry. Whether or not you get vegan BCAAs is a matter of chance, as the company doesn't label its shipments one way or another. RULE1 claimed supply shortages when we asked why there was inconsistency in its ingredient sourcing, but other companies seem to have no problem consistently producing vegan BCAAs.

Taste and mixability

RULE1’s taste won’t be for everybody. It’s certainly better than an unflavored amino acid powder dissolved in water, but it has an artificial taste that didn’t appeal to our testers (we tried the black cherry limeade). This is likely due to the sucralose used as a sweetener, but the use of artificial flavors couldn’t have helped. And despite all that, we could still taste that distinctive, unvarnished amino acid flavor lingering in the background. If mixing it with water were your only option, it’d be a better choice than an unflavored powder, but since you can't add RULE1 to things like smoothies or bone broth the way you can an unflavored amino acid supplement, its taste becomes a more serious hurdle.

RULE1 comes in six flavors:

• Rainbow Candy
• Peach Mango
• Blue Razz Lemonade
• Black Cherry Limeade
• Fruit Punch
• Sour Watermelon

It’s possible that one of these other flavors would perform better than the black cherry limeade, but we aren’t holding out hope.

RULE1’s Essential amino 9 mixed about as well as Type Zero Clean Amino Burn. In the “cool water” test, it stirred in almost completely with just a few small clumps and a little settling out at the bottom of the glass. It would mix in completely with a shaker cup or blender.

Pricing

You can only purchase RULE1 Essential Amino 9 one transaction at a time, with no discounts for bulk purchases and no option to subscribe. A single container costs $29.99, or roughly $1/serving.

The only way to save a little money on your RULE1 purchases is to be part of its reward program, which is free to join and offers points for the following activities:

A single container of Essential Amino 9 costs 6,000 points. To get that many, you’d have to sign up, follow the company on Instagram, celebrate a birthday, and purchase just under $450 worth of goods. If all you buy from the company is this product, it will take you about 14 months to get your first free container and 20 months per free container after that. Naked Nutrition is the only other company in our guide to offer a loyalty program, but its system is both more complicated and less rewarding.

Shipping from RULE1 costs $10 for orders under $100 and is free on orders above that point. This is the most expensive shipping among its closest competitors, though some of them have higher thresholds for free shipping.

Best budget pick

Bulk Supplements consistently offers top budget picks for many of the products we test and review. There’s rarely anything fancy about its offerings, but each product is subjected to third-party testing after being manufactured in NSF-certified and FDA-registered facilities.

You can get Bulk Supplements EAA Powder in a handful of sizes, from a small 100g pouch to a 55lb drum. The savings at the 55lb level are absurd, but so is the thought of keeping a giant barrel full of EAA powder in your kitchen! Instead, to make our value determination, we looked at the 500g package. This delivers the same number of servings as Naked Nutrition’s EAAs, which could be considered a runner-up for the budget-conscious.

There are some trade-offs, however. Instead of a convenient container with a measuring scoop, Bulk Supplements ships its EAA Powder in pouches with no scoop in sight. You’ll have to measure your powder with a scale, at least until you get to a point where you can eyeball it. And despite having the highest amino acid dose of the products in our guide, Bulk Supplements keeps individual quantities a secret in a “proprietary blend.” We dislike that lack of transparency.

Taste and mixability

Bulk Supplements scored almost identically to Naked Nutrition in terms of both taste and mixability. Like most unflavored amino acid supplements, this one tastes bad but mixes well. We found that Naked Nutrition’s EAAs mixed into cold water more thoroughly and with a little less effort than Bulk Supplements’ EAA Powder, but the difference was negligible. Again, you won’t be drinking this or any other amino acid supplement in plain water; we only use it as a benchmark for mixability. It’ll mix well into any flavored beverage or smoothie, which (if robust enough) will mask the natural flavor of the powder.

Pricing

As we mentioned above, Bulk Supplements offers its EAA Powder in several quantities. We’ll use a handy chart to break it down for you, but note that prices for this product fluctuate quite often, typically going up or down by a few dollars:

Any purchase of 1kg or less is too inexpensive to qualify for the $59 free shipping threshold, so you’ll end up paying $10 to ship each order.