Best Supplements for Triathletes
Triathlon stacks three endurance sports with massive weekly training loads. Nutrition isn't a stack — it's a system: daily recovery, race-day fueling, and gut adaptation.
Daily Foundation
- Whey or vegan protein — 1.4–1.8 g/kg/day. Endurance athletes chronically under-eat protein.
- Omega-3 (EPA + DHA) — 2–3 g/day. Inflammation control and recovery.
- Vitamin D3 + K2 — 2,000–5,000 IU. Bone health and immune function.
- Iron — only if ferritin <50 ng/mL. Test, don't guess.
- Magnesium glycinate — 300–400 mg PM. Sleep and cramp prevention.
- Creatine monohydrate — 3–5 g/day. Yes, even for endurance: preserves lean mass and supports neuromuscular function across long blocks.
Pre-Race
- Beetroot nitrate — 6.4 mmol/day, 3–6 days pre-race (best for Olympic distance and shorter).
- Caffeine — 3–6 mg/kg, 45–60 min pre-race. Re-dose mid-race for half/full Ironman.
- Sodium-loading — 1,500–3,000 mg sodium in the 90 min pre-race.
In-Race Fueling by Distance
Sprint (≤90 min)
Water, electrolytes, optional 30 g carbs/hour, caffeine.
Olympic (2–3 hours)
60–80 g carbs/hour, 500–800 mg sodium/hour, water to thirst.
Half Ironman (4–6 hours)
80–100 g carbs/hour (gel + drink mix mix), 700–1,200 mg sodium/hour, caffeine in the back half of the bike and run.
Ironman (9–17 hours)
90–120 g carbs/hour (gut-trained athletes), 1,000–1,500 mg sodium/hour, plus solid food on the bike (rice cakes, bars, bananas). Manage caffeine in pulses to avoid GI crash.
Post-Race & Daily Recovery
- 20–40 g protein within 60 min, plus 1–1.5 g/kg carbs.
- Tart cherry juice or curcumin (with phospholipid carrier) for inflammation post-key sessions.
- Sleep is the most undervalued supplement: 8–9 hours/night during build phases.
The Bottom Line
A triathlete's edge isn't a magic powder — it's a fueling system trained as carefully as the swim, bike, and run. Build the foundation daily, train the gut for race-day carb intake, and never skimp on sodium.
Frequently Asked Questions
- How many carbs per hour during an Ironman?
- 90–120 g/hour for trained athletes using a 2:1 glucose-to-fructose ratio. This requires gut training over 8–12 weeks — most athletes start at 60 g/hour and build up.
- Should triathletes take iron?
- Test before supplementing. Up to 35% of female endurance athletes and 10–15% of males are iron-deficient. Foot-strike hemolysis from running plus chronic inflammation make triathletes high-risk. Target ferritin >50 ng/mL.
- Is sodium more important than I think?
- Yes. Heavy sweaters lose 1,500+ mg sodium per hour. Cramping, late-race fade, and hyponatremia all trace back to under-sodiumed fueling. 500–1,000 mg sodium per hour is standard.
