Ferrous Sulfate18–36 mg · any
Iron carries oxygen to your muscles. Even mildly low iron drags your capacity down.
Solid · 1 study, positiveResearch →
energy metabolism · symptom
Low Stamina
Running out of steam sooner than you used to.
Top proven supplements
Studied in people, at a dose you can actually buy.5Studied in people, at a dose you can actually buy.
Beta-Alanine3.2–6.4 g · any
Builds up a buffer in your muscles that holds off the burn during hard efforts.
Strong · 1 study, positiveResearch →
CoQ10100–300 mg · with_food
Your muscles need CoQ10 to make energy with oxygen, which is what endurance runs on.
Solid · 3 of 3 studies agreeResearch →
Rhodiola200–400 mg · morning
Helps your body recycle energy faster and use oxygen better during exercise.
Solid · 2 of 2 studies agreeResearch →
BCAAs5–20 g · any
Tells your muscles to rebuild, and limits the damage hard training does.
Strong · 3 of 3 studies agreeResearch →
Might help
Real research, but thin or split. Worth knowing, not worth counting on.4Real research, but thin or split. Worth knowing, not worth counting on.
Beetroot (Dietary Nitrate)300–600 mg · any
Lowers the oxygen cost of exercise, so you can keep going longer at the same effort.
Mixed · 1 of 2 studies positiveResearch →
L-Carnitine1000–2000 mg · any
Helps you burn fat during exercise, sparing the stored carbohydrate you need later.
Mixed · 3 of 5 studies positiveResearch →
Tongkat Ali200–400 mg · any
Thought to support testosterone, which in turn supports physical performance.
Mixed · 2 of 3 studies positiveResearch →
Maca1500–3000 mg · any
Its plant compounds appear to lift energy and endurance.
Mixed · 1 of 3 studies positiveResearch →
Tested — didn’t work
Measured properly against placebo. Nothing found.1Measured properly against placebo. Nothing found.
Phosphorus700–1000 mg · any
Needed to build ATP, the molecule your muscles actually spend as energy.
No benefit foundResearch →
No research yet
People take these for it. We haven’t found trials we would stand behind.5People take these for it. We haven’t found trials we would stand behind.
Iron18–36 mg · empty_stomach
Iron carries oxygen to muscle. Even mildly low iron cuts what you can do.
No trials we can vouch forResearch →
Selenium50–200 mcg · with_food
No trials we can vouch forResearch →
L-Citrulline6–8 g · any
Raises the compound that widens blood vessels, getting more oxygen to working muscle.
No trials we can vouch forResearch →
Creatine3–5 g · any
Recharges the fast energy system your muscles use for short, hard efforts.
No trials we can vouch forResearch →
Cocoa Flavanols1000 mg · any
Meant to improve blood flow to working muscle, so you last longer.
No trials we can vouch forResearch →