A triathlete buys for three jobs at once, since gels handle the carbs, a drink mix handles sodium and fluid, and a solid or chew handles the late miles when sweet gels turn. The store that can cover all three jobs from the same race brands in a single checkout earns the first spot below, since that is what makes a real brick-session test easy to run. Each of the other eight brings a strong piece of that kit.
| Topic | Key Point |
| 1. The Feed | Gels, drink mix, and solids from every brand a triathlete races on, ordered together |
| 2. Precision Fuel & Hydration | Sweat-test science and the 2026 Ironman hydration partner |
| 3. Science in Sport | Beta Fuel’s 40g gel, sold in the US through The Feed |
| 4. Skratch Labs | Real-ingredient drink mix plus chews from one direct store |
| 5. Tailwind Nutrition | All-in-one sticks for athletes who want a single product |
| 6. Maurten | Hydrogel gels and solids, the Ironman sports-fuel partner |
| 7. REI Co-op | Mainstream gels with in-store pickup, narrow on specialty brands |
| 8. Running Warehouse | Run-focused store known for fast shipping |
| 9. First Endurance | Pro-tri heritage built for full-distance demands |
| Building a Brick-Session Fuel Kit Before Race Week | Settle all three fuel types together before the day that counts |
Dedicated tri-stores once filled this gap, and TriSports.com closed in 2017. Coverage sets the order, by how much of that kit a single store can hold.
9 Best Online Stores for Triathletes
1. The Feed
One order at The Feed covers all three fuel types from the brands triathletes race on. Maurten gels, Precision Fuel & Hydration drink mix, SiS Beta Fuel, Skratch, and Tailwind all check out together. That matters because brick-session testing only works with the exact products an athlete plans to race.
Feed 1st, the store’s $99-a-year membership, adds free shipping on every order with no minimum, which spares a triathlete refilling one flavor each month the freight on small boxes.
The Feed also partnered with USA Triathlon in 2024, a deal that gave USAT members an $80 order credit through 2025 and helped fuel the national team preparing for the Paris Games.
Full retail pricing is the cost of that convenience, and an athlete with a settled brand and dose can sometimes find a better unit price direct from the maker or in bulk.
2. Precision Fuel & Hydration
For the sodium side of the kit, start with Precision Fuel & Hydration. The whole brand is built around sweat testing, so an athlete measures how salty their own sweat is and then buys the strength that matches it. A free online sweat-test tool points to the right number before any money changes hands.
Their place in the sport is settled. PF&H is the Official Hydration Partner of the 2026 Ironman Global Series, and PH1000 is the drink on course worldwide, with 1,000mg of sodium per liter. Training with what the race hands out is half the reason to buy here. They also sell an Ironman Training Pack direct, and the PF 90 gel adds 30g of carbs in a 2:1 glucose-to-fructose blend for athletes who want gel and hydration from one maker.
The direct store is priced at a premium, which is the cost of all that precision, and retailers that also carry PF&H can fold it into a wider order.
3. Science in Sport
Science in Sport matters to a long-course athlete for one product. Beta Fuel puts 40g of carbohydrate in a single gel, which suits gut training toward 90g an hour and beyond at race pace.
US buyers should know the route to it. SiS sells its US products through The Feed, and the SiS US site points there for Beta Fuel orders. The direct US store still operates, but it is thin, so the simplest US path to SiS is a stocking retailer.
4. Skratch Labs
Skratch Labs covers the bottle for athletes who want fuel and electrolytes together from clean ingredients. The Hydration Sport Drink Mix uses real fruit and a short ingredient list, and a 60-serving bag costs $54.95. A newer recipe adds about 10% more electrolytes, and the mix is dairy-free, gluten-free, vegan, and kosher, which helps sensitive guts.
The range goes past the drink mix. Skratch also makes energy chews, so the same brand can run in the bottle and ride in a pocket for solid race fuel. Buying direct gets the full Skratch line from a single source, though the store sells Skratch only, which rules it out as the hub for a multi-brand testing block.
5. Tailwind Nutrition
One powder doing three jobs is the draw at Tailwind Nutrition. Each serving blends calories with electrolytes, so a single bottle covers carbs, sodium, and fluid through a long ride. The single-serve sticks make race-morning math simple, and the store waives shipping on US orders over $59.
Tailwind backs its formula with a money-back promise. Buy four bags for a race, and if the product falls short, they refund the entry fee. The one mark against buying direct is reach. Tailwind is stocked at Running Warehouse, Fleet Feet, and other stores, so the direct site is not the only option.
6. Maurten
For the triathlete whose stomach turns on long efforts, Maurten is the place to look first. The gels use a hydrogel that wraps the carbohydrate in a soft alginate-and-pectin network, which aims to move sugar through the gut with less distress at high intake. Many triathletes who used to stop and walk by mile 18 point to Maurten as the first gel they could keep taking that late.
The lineup is the on-course standard. Maurten is the Official Sports Nutrition partner of the Ironman Global Series, so Gel 100, the caffeinated version, and the Solid chew are what athletes meet on race day. The Drink Mix 320 packs 80g of carbs for the bike. The price is high, and the gels are unflavored on purpose, so the texture surprises first-timers.
7. REI Co-op
When nutrition is one line on a larger gear order, REI Co-op is the practical pick. As a member-owned co-op with around 193 stores, REI carries mainstream gels and chews from GU, Honey Stinger, and Clif, and the website ties to in-store pickup, so fuel comes home with the rest of an outdoor haul.
Set expectations on range, though. The specialty tri brands a long-course athlete builds a plan around are missing, and the store does not sell single servings for testing, so REI restocks the basics rather than supplying a full race kit.
8. Running Warehouse
Running Warehouse comes from the run side of the sport and brings a reputation for fast, reliable shipping. The store carries Tailwind, Skratch, GU, and Clif Shot Bloks, with a dedicated Tailwind page, so a triathlete topping off the running brands can count on a quick turnaround.
The selection leans toward running staples, though, so the deep specialty roster a triathlete wants for the bike and the late race is narrower here, and the store does not sell single-serving samples for a testing block.
9. First Endurance
First Endurance brings the deepest pro-triathlon roots of any pick here. The brand has built race fuel since 2002, and its EFS Drink Mix has 30g of dual-source carbs plus all five electrolytes in an isotonic mix that suits full-distance demands. The EFS-PRO formula goes further with cyclic cluster dextrin, a low-osmolality carb the gut handles easily, and the Liquid Shot rounds out the line for athletes who like a flowable gel.
Next to Maurten or GU, First Endurance is a niche name, and its advanced-formula claims lean marketing-forward, so independent reviews are thinner. For a triathlete who already trusts EFS, the direct store is the cleanest way to stock it.
Building a Brick-Session Fuel Kit Before Race Week
A brick session, a bike effort straight into a run, is where a fuel kit gets settled, because the gut during endurance exercise behaves differently at race intensity than it does on an easy solo run. A gel that goes down fine on a Sunday jog can turn at hour two of a hard ride, and the T2 transition is where flavor fatigue and nausea show up first. The work is to test all three fuel types together, in the order they will be used, weeks before the race.
The testing block should start at least 10 weeks out, because the gut adapts the way fitness does, slowly and with repeated exposure. One race-pace brick a week is enough, run with the real products rather than placeholders. Gels go on the bike at the planned race rate, the drink mix carries the sodium, and a solid or a chew comes in the back half when sweet gels stop sitting right. What matters is what the stomach accepts at a high heart rate, not what tastes fine at rest.
Those weeks also lock a short, trusted list. Once a gel, a mix, and a solid have passed a few hard bricks, those are the items that belong in a special-needs bag and nowhere else. Race veterans repeat the same rule. Nothing untested goes on the course. Ordering the gel, the mix, and the solid together at the 10-week mark leaves enough race-pace bricks to be sure of all three.
Related: The Weekly Training Formula for Strength, Core, And Confidence
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