Supplements that actually work — the AIS ABCD framework for runners
Most of the supplement aisle is theatre. These are the ones with real evidence and real effect sizes, and the doses that match the literature.
The Australian Institute of Sport's ABCD framework is the global gold standard for sports-nutrition supplement classification. Category A: strong evidence, recommended. Category B: emerging, requires individual trial. Category C: little to no evidence. Category D: banned or contamination risk. Here are the Category A supplements that matter for runners.
Caffeine — the most robustly ergogenic supplement in endurance sport, with meta-analytic 2–4% time-trial improvement across distances. Dose: 3–6 mg/kg, 45–60 min pre-exercise (Spriet, Sports Medicine, 2014; Grgic et al. meta-analysis, IJSNEM, 2020). Mechanism: adenosine receptor antagonism, reducing perceived exertion. CYP1A2 genotype moderates response — AA-genotype fast metabolisers (~50% of population) gain more; AC/CC slow metabolisers may even be impaired at 4 mg/kg (Guest et al., MSSE, 2018). Daily caffeine habituation blunts but does not eliminate the ergogenic effect (Lara et al., JAP, 2019). Removed from the WADA prohibited list in 2004; legal and safe when dosed correctly.
Creatine monohydrate — once dismissed as power-sport only, now well-evidenced for runners. Forbes et al. (Sports Medicine, 2023) and Kreider et al. (JISSN, 2017) document benefits for: repeated sprint performance, lean mass preservation in masters runners with age-related sarcopenia, cognitive function during sleep-deprived ultra-endurance, and faster recovery between hard sessions. Dose: 3–5 g/day continuous maintenance; optional 20 g/day loading for 5–7 days. No kidney harm in healthy individuals. Intracellular-water weight gain of 0.5–1.5 kg is real. Masters runners are the highest-yield target population.
Beta-alanine — ergogenic for events requiring 1–10 minutes of sustained high intensity (ISSN position stand, JISSN, 2015). Useful for 800 m–mile racers; modest for 5K; minimal for marathon. 3.2–6.4 g/day in divided doses (to avoid paresthesia); takes 4+ weeks of loading.
Dietary nitrates (beetroot juice) — enhance nitric oxide availability, improving exercise economy. Dose: 6.4–12.8 mmol nitrate (400–800 mg), 2–3 hours pre-exercise (Bailey & Jones, University of Exeter). Stronger effects for 5K–10K than marathon; greater effect in recreational than elite athletes. Protocol: 2 × 70 mL Beet It Sport concentrated shots 2.5 hours pre-race, loaded for 3–6 days before.
Vitamin D — deficiency prevalent in runners, especially winter training in northern latitudes. Target: serum 25(OH)D 30–50 ng/mL. Supplementation: 1,000–2,000 IU/day baseline, up to 4,000 IU with physician oversight when deficient. Consequences of deficiency: impaired bone remodelling (stress-fracture risk), blunted immunity, suboptimal muscle function.
Iron — the most commonly deficient micronutrient in runners. Running-specific mechanisms: foot-strike hemolysis, exercise-induced hepcidin elevation reducing absorption 3–6 hours post-session (Peeling et al., JAP, 2009), sweat and GI losses. Ferritin targets for runners: >35–50 ng/mL minimum, ideally >50 ng/mL. Iron bisglycinate has superior bioavailability and GI tolerance versus ferrous sulfate. Stoffel et al. (Lancet Haematology, 2017) demonstrated that alternate-day dosing outperforms daily dosing due to hepcidin dynamics — a paradigm-shift still under-implemented. Co-ingest with vitamin C; avoid calcium, tea/coffee, dairy within 2 hours. Never supplement without a ferritin test.
Omega-3 (EPA + DHA) — 2–4 g/day combined reduces inflammatory markers and DOMS. Algae-based options for vegans.
Collagen peptides + vitamin C — Shaw et al. 2017 (AJCN) showed that 15 g of gelatin or collagen peptides with 50 mg vitamin C, 1 hour pre-exercise, doubles collagen synthesis markers and supports connective-tissue recovery. Keith Baar's UC Davis lab extended this to tendon-rehab protocols. Under-used and evidence-rich.
Tart cherry (Montmorency) — 480 mg capsule equivalent or 8–12 oz concentrate, twice daily for 5 days pre-race and 2 days post, reduces marathon recovery markers and DOMS (Howatson et al., SJMSS, 2010).
Category C (unsupported): BCAAs (redundant when daily protein is adequate). MCT oil (does not enhance endurance). Alkaline water and oxygen drops (no). Most greens powders (marketing).
Category D (banned or risky): WADA prohibited items. 10–25% of non-certified supplements have been found contaminated with banned substances (Outram & Stewart, IJSNEM, 2015). Every supplement for a competitive runner should carry NSF Certified for Sport, Informed Sport, or Informed Choice.