Evidence B · Good (stress/fatigue) / C for pure performance
Water-soluble
Chronic (2–8 weeks)
A traditional adaptogen from Scandinavian/Russian medicine. It acts by modulating the HPA axis (hypothalamic-pituitary-adrenal), reducing the excessive response to physical and mental stress. The main actives are rosavins and salidroside — the classic standardized extract contains 3% rosavins + 1% salidroside (a 3:1 ratio).
Dose200–600 mg/day (standardized extract)
TimingMorning (or 30–60 min pre-workout)
FoodIndependent
Standardization3% rosavins + 1% salidroside
Why it makes sense for ultramarathon runners
- Cortisol modulation: high training volume + a caloric deficit keeps cortisol chronically elevated, impairing recovery, sleep and body composition. Rhodiola reduces this excessive response.
- Central fatigue: it lowers the perception of effort (RPE) on long runs — you "feel" the mental fatigue less at 60–80% of the race.
- Time to exhaustion: some RCTs show a modest increase in time-to-exhaustion after chronic use (4 weeks).
- Mental focus: useful in long races where technical decisions (where to step, pacing strategy) are affected by fatigue.
Recommended product
Life Extension's Rhodiola Extract (250 mg per capsule, standardized to 3% rosavins + 1% salidroside) is a solid option with a good cost-benefit ratio and reliable standardization. Take 1–2 capsules in the morning.
How to use (practical protocol)
- Starting dose: 250 mg in the morning, fasted or with breakfast.
- After 1–2 weeks: increase to 500 mg/day (1 capsule in the morning + 1 capsule in the early afternoon) if you feel a benefit.
- Acute pre-workout: 30–60 min before training (200–300 mg). It does not increase raw strength, but it reduces the perception of fatigue.
- Cycling: 8 weeks on / 2 weeks off — as with many adaptogens, this avoids HPA-axis "tolerance".
What NOT to expect
- Immediate stimulation like caffeine — Rhodiola is subtle. The real effect appears only after 2–4 weeks.
- An increase in strength or power (it is not a classic ergogenic aid).
- A substitute for poor sleep — adaptogens compensate, they do not restore.
⚠️ Warning: Rhodiola may interact with antidepressants (SSRIs, MAOIs) — risk of serotonin syndrome. It may also interfere with thyroid medications. Consult a doctor if you use any of these.
Synergy with other supplements
- + Magnesium Bisglycinate (night): dual cortisol reduction + better sleep.
- + ALCAR + Coffee (morning): a "morning mental focus" combo without anxiety.
- + Trans-Resveratrol: both act on cellular longevity pathways.