The Honest Read
This comparison gets framed as a head-to-head, but it's really two tools that belong in different toolboxes — or, better yet, in the same toolbox together. Hexis handles the 22 hours of the day when you're not on the bike. Precision Fuel & Hydration handles the 2 hours when you are. The overlap between them is narrow, and the complementary value is high.
What Hexis does. Hexis runs the FFTWR methodology developed by Dr Sam Impey and Professor James Morton at Liverpool John Moores University — the same periodised nutrition framework adopted by Ineos Grenadiers, EF Education-EasyPost, Tudor Pro Cycling, and other WorldTour teams. The engine sorts your days into seven fuel categories from REST through VERY_HIGH and adjusts your macros accordingly. On a rest day, carbs drop and protein stays stable. On a hard training day, carbs scale up with specific restoration factors. On a competition day, carb-loading kicks in with a 40g bonus and near-full calorie restoration. The system covers breakfast through to your last meal — it's a framework for daily eating, periodised to match what your body actually needs that day. The fuelling calculator runs the same methodology if you want to test the approach.
What Precision Fuel & Hydration does. PF&H started with a simple insight: sweat composition varies enormously between athletes, and most cyclists have no idea what they're losing or what they need to replace. Their sweat testing service ($180 per session) measures your sodium concentration and sweat rate under controlled conditions, then maps you to the right electrolyte strength from their multi-concentration product line. The free Fuel & Hydration Planner builds hour-by-hour race-day plans based on event duration, intensity, conditions, and your sweat data. Their product range — drink mixes, gels, chews — is formulated to slot into those plans. It's precise, science-backed in-ride fuelling.
The gap between them, plainly. Hexis doesn't tell you how many grams of carbohydrate to consume per hour at race intensity, or which electrolyte concentration matches your sweat sodium levels. Precision Fuel & Hydration doesn't tell you how many grams of protein to eat at breakfast on a rest day, or how your daily carb intake should differ between a Zone 2 base day and a VO2max interval day. They're solving different problems. A cyclist who uses Hexis for daily periodisation and PF&H for in-ride fuelling has both problems covered. Most cyclists have neither covered. For the hydration calculator, the free tool estimates your baseline needs.
Do you need both? If you had to pick one starting point, ask yourself where your nutrition is weakest. If you bonk on long rides, can't sustain race intensity past two hours, or have never thought about your sodium losses — start with PF&H. If your daily eating is chaotic, you're unsure how to adjust macros around training, or you're trying to manage body composition without sacrificing performance — start with Hexis. If you're serious about both daily periodisation and race-day execution, use both. They don't conflict; they complement.
On the product model. Hexis is pure software — a monthly subscription that tells you what to eat, built around whatever foods you prefer. PF&H is part software (free planning tools), part testing service ($180 sweat test), and part product company (their own fuelling products). You can use PF&H's planning tools and sweat data with any brand's products, but their formulations are designed to match the plans precisely. The business models are different, which means the cost comparison isn't apples to apples. Hexis is a monthly fee. PF&H is a testing fee plus ongoing product purchases. Compare them on what they do for your nutrition, not on sticker price.
The recommendation. Both are credible, science-backed, and used at the highest level of the sport. They're not competitors — they're collaborators in a complete nutrition strategy. Start with whichever addresses your bigger gap, then add the other when your foundation is solid. If your daily nutrition is already periodised and your in-ride fuelling is dialled, you probably don't need either. But most cyclists aren't in that position.
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FAQ
Do I need both Hexis and Precision Fuel & Hydration?
You don't need both to start, but a cyclist using both has better coverage. Hexis handles daily macro periodisation — what you eat across all meals, adjusted to training load. PF&H handles in-ride fuelling and hydration — what you consume during sessions and races. They solve different problems with minimal overlap. Start with whichever addresses your bigger weakness.
Does Hexis cover hydration?
Hexis provides general hydration guidance but doesn't offer sweat-rate testing, sodium-concentration analysis, or multi-strength electrolyte recommendations. Those are PF&H's core competencies. If hydration and in-ride electrolyte strategy are your priority, PF&H is the specialist tool for that problem.
Does Precision Fuel & Hydration cover daily nutrition?
No. PF&H focuses on in-ride and around-session fuelling and hydration. It doesn't provide daily macro targets, meal-level periodisation, or training-day calorie adjustment. If your question is what to eat across the day based on your training load, that's Hexis's domain, not PF&H's.
Which should I start with?
Ask where your nutrition breaks down. If you bonk during rides, struggle with hydration in heat, or have never had your sweat tested, start with Precision Fuel & Hydration. If your daily eating is inconsistent, you don't adjust macros around training, or you're managing body composition alongside performance, start with Hexis. The entry cost for PF&H is the sweat test ($180); for Hexis it's the monthly subscription (~$20).
Can I use PF&H's planning tools without buying their products?
Yes. The online Fuel & Hydration Planner is free and gives you hour-by-hour carb and fluid targets regardless of which brand's products you use. The sweat test data is yours to apply however you like. PF&H's products are formulated to match their plans precisely, but the planning framework works independently of the product line.