30 Servings/Container


EFS Electrolyte Drink

So much more than just a hydration mix

The new EFS provides premium nutrition that supports physical and mental performance for elite athletes, redefining the limits of endurance nutrition so you can redefine the limits of endurance.

✓ Improves mental toughness & sharpens your competitive edge
✓ Prevents cramping & helps you hydrate fast
✓ Provides immediate & sustained fuel when you need it most



Fruit Punch & Lemon Lime are Out Of Stock
Estimate in-stock date: 3/11/21

A new way of thinking

When we think about endurance sports, we don’t typically think about thinking, but anyone who’s had their motivation crushed by an obstacle—a looming climb, a 90-degree turn into a headwind, another gap to close—knows that mental toughness and presence of mind at critical moments are almost as important as fitness.

That’s why we designed the new EFS to increase Alpha brain waves while decreasing Beta brain waves so you’ll have the mental toughness it takes to push your body to the limits when it matters most.

“The new EFS drink mix tastes great, helps keep you focused during long and hard training sessions, and fuels the body properly.”

Matt Hanson

5x IRONMAN / 5x 70.3 Champion / Holds the record for the fastest full-distance IRONMAN (7:39:25)


Suntheanine® L-theanine is a mind-over-matter compound for maximizing your brain’s control over exercise performance.

The brain plays a key role in endurance. Keeping your brain in the game strengthens your resolve at those decisive moments that can make the difference between success and failure.

This means you can dig deeper into your reserves and react better when everyone is suffering, because you’ll be less influenced by that little voice inside your head that’s screaming at you to stop.

Suntheanine® is protected by over 40 U.S. and international patents for its various physiological efficacies and L-isomer specific production processes.

Performance benefits

  • Suntheanine® boosts mental toughness to help you push through suffering
  • Industry-leading electrolyte content—nothing is better at preventing cramps
  • Carbs from multiple sources provide immediate and sustained fuel
  • 7% osmolality ensures bioavailability and reduces GI distress
  • Citric and malic acids promote oxygen uptake and energy production
  • New taste profile eliminates the flavor vs function compromise

All you need to push your limits

In addition to unlocking the mental game, EFS pushes cramp prevention and continuous fueling to new levels.

It includes all five electrolytes totaling 1,160mg. That’s twice the amount of traditional mixes, and—since we improved the flavor—it tastes great at full concentration (or beyond).

There’s no need to dilute it and supplement with electrolyte tabs just to make it palatable. It’s also got more carbs from more sources, including complex carbs for prolonged energy and high-glycemic carbs for immediate use.

“It tastes great and I love the way it made me feel.”

Seth Jones

Pro Cyclist (Hincapie Racing Team)

“Definitely love the new flavors of EFS.”

Tina Pic

Pro Cyclist & 6x USA Criterium Champion

Bioavailability is the best ability
From the carbohydrates (osmotically balanced with your body in a 7% solution) to the electrolytes (20-100% better absorption rates), every ingredient in EFS is selected and portioned for faster and easier absorption without GI distress.

The inclusion of citric and malic acids also encourages oxygen uptake and production of ATP (the body’s energy source), helping your cells use the fuel once it’s delivered.

Premium ingredients for purity and purpose
We prioritize purity by using only Suntheanine, the original and cleanest L-theanine, and free-form amino acids, which have a purity level of 99-100%.

We also omit ingredients with no value—even the ubiquitous vitamin C, which features in virtually every other mix despite research that shows it reduces endurance when taken during exercise. EFS still provides immune system support courtesy of theanine, just without impacting performance.

No respect for the status quo
Our approach to product design eschews unexamined ingredients, traditional processes, and trendy minimalism in favor of research-based innovation, premium ingredient sourcing, and the uncompromising expectations of elite athletes. We’re always ready to show our work and support our products with the scientific literature that informs our design choices, but we also know what virtually every athlete and publication using or reviewing our products learns firsthand: First Endurance products speak for themselves, and you can feel the difference right away.

“Beyond the importance of Suntheanine, I think the new flavors are the biggest advancement.”
Jeffrey Rocco, MD

A system that puts endurance first

EFS is for use during exercise to prevent cramps, maintain fuel levels, and support mental toughness when it’s needed most. It can be supplemented with Liquid Shots and PreRace before and during an event, respectively, and Ultragen helps consolidate gains during recovery between sessions.

Regardless of your training load, a daily dose of our MultiV and Optygen lines help you lay a foundation to achieve your goals.

“On-the-bike taste was great. I felt amazing on the bike today! I had a PR on the top half of the climb. Surprised by this, because I had skied hard the day before.”

Doug Davis

Cat I Cyclist


Locked in a Vault – Coming Soon


Q: I am prone to cramping during longer training and racing. Will EFS help me with cramping problems?


A: Nutritionally, cramping stems from electrolyte imbalance, electrolyte depletion and/or dehydration. EFS provides the most potent electrolyte profile available. The combination of all five electrolytes delivers a potent 1160mg per serving, helping to prevent cramping. The 300mg sodium per serving also aids in maximum fluid absorption so you stay hydrated throughout your training and racing. Supplementing with additional salt tabs, electrolyte tabs, or salty snacks is no longer needed when using EFS.



Q: How much EFS should I use during my training and racing?


A: Clinical research shows that a 6-8% solution delivering between 45-60g carbohydrates, >1000mg amino acids, 400-600mg sodium and equivalent balance in all electrolytes should be taken every hour during exercise. Athletes should consume one serving for every 30 minutes of intense exercise. Adjustments should be made based on body weight, training state, heat, individual sweat rates and preference. Use one serving for every 30 minutes as a starting point and adjust as necessary from there.  Additional calories and electrolytes can be added with EFS liquid shots.

Q: I’ve heard that there are benefits to having protein during exercise. Why doesn’t EFS contain protein?

A: EFS contains 2g free form amino acids per serving which is the equivalent in BCAA and glutamine profile to 9g whey protein. Protein naturally contains BCAAs and glutamine.

Clinical evidence supporting the use of BCAAs and glutamine during exercise dates back to 1991. These clinical studies clearly indicate supplementing with as little as 1g free form amino acids improved performance, reduced post-exercise muscle damage, improved muscle glycogen resynthesis, reduced central fatigue and improved rate of perceived exertion. These are the same claims made by the most recent protein study and clearly support a mechanism for improved performance.

In addition to the clinical support, other factors lead to a decision to use these free form amino acids over complete proteins.

  • Proteins are more difficult to digest than amino acids during exercise
  • Proteins don’t taste very good during exercise
  • Proteins can reduce the glycemic index of a drink, further reducing its ability to be quickly absorbed
  • There is considerably more evidence supporting free form amino acids than complete proteins



First Endurance offers everything an endurance athlete needs to maximize endurance and performance.  We designed it to work as a complete endurance system. Each product has a specific purpose and complements the others.

With First Endurance, there’s no more guesswork.