Supplements for endurance

7 compounds relevant to endurance, ranked by overall evidence grade.

Overall grade: Grade A
Last revised: Jul 10, 2026; 7
graded outcomes: 0
references listed

Assembled by the app from other entries in this library. It adds no evidence of its own — follow the links to the entries it draws on.

3 at grade A · 1 at grade B · 2 at grade C · 1 at grade D — 7 graded rows

What is known

Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.

Outcome	Grade	Effect size	Agreement
IronOnly supplement it against a ferritin number — transformative in deficiency, pro-oxidant and constipating in excess.	Evidence grade A	Unclear	mixed
Beta-AlanineBuffers the acid burn of 1–4 minute efforts — one of the better-supported performance supplements, tingle and all.	Evidence grade A	Unclear	mixed
CaffeineThe most-used and best-evidenced cognitive and physical stimulant on earth — precise dosing and a hard afternoon cutoff are the whole skill.	Evidence grade A	Unclear	mixed
Beetroot / Dietary NitrateDietary nitrate lowers the oxygen cost of exercise — a legit endurance aid, best in recreational athletes.	Evidence grade B	Unclear	mixed
TaurineA conditionally-essential amino acid with broad but mostly modest effects on exercise, blood pressure, and metabolic markers.	Evidence grade C	Unclear	mixed
GlycerolA hyperhydration agent that expands fluid volume for hot-weather endurance — real but niche.	Evidence grade C	Unclear	mixed
CordycepsA popular endurance mushroom whose human performance data are weak and inconsistent.	Evidence grade D	Unclear	mixed

IronEvidence grade A
Only supplement it against a ferritin number — transformative in deficiency, pro-oxidant and constipating in excess.
Unclearmixed
Beta-AlanineEvidence grade A
Buffers the acid burn of 1–4 minute efforts — one of the better-supported performance supplements, tingle and all.
Unclearmixed
CaffeineEvidence grade A
The most-used and best-evidenced cognitive and physical stimulant on earth — precise dosing and a hard afternoon cutoff are the whole skill.
Unclearmixed
Beetroot / Dietary NitrateEvidence grade B
Dietary nitrate lowers the oxygen cost of exercise — a legit endurance aid, best in recreational athletes.
Unclearmixed
TaurineEvidence grade C
A conditionally-essential amino acid with broad but mostly modest effects on exercise, blood pressure, and metabolic markers.
Unclearmixed
GlycerolEvidence grade C
A hyperhydration agent that expands fluid volume for hot-weather endurance — real but niche.
Unclearmixed
CordycepsEvidence grade D
A popular endurance mushroom whose human performance data are weak and inconsistent.
Unclearmixed

What is uncertain

Read off the same rows as above. Nothing here is added that the entry does not itself record.

Thin evidence: Taurine (grade C); Glycerol (grade C); Cordyceps (grade D).
Studies disagree: Iron (mixed agreement); Beta-Alanine (mixed agreement); Caffeine (mixed agreement); Beetroot / Dietary Nitrate (mixed agreement).

The evidence in words

The shortlist

Every compound in the knowledge base tagged to endurance, ordered by how strong its overall evidence is. Start at the top; the grade is the honest filter.

Worth considering first

Iron (A) — Only supplement it against a ferritin number — transformative in deficiency, pro-oxidant and constipating in excess. · Beta-Alanine (A) — Buffers the acid burn of 1–4 minute efforts — one of the better-supported performance supplements, tingle and all. · Caffeine (A) — The most-used and best-evidenced cognitive and physical stimulant on earth — precise dosing and a hard afternoon cutoff are the whole skill. · Beetroot / Dietary Nitrate (B) — Dietary nitrate lowers the oxygen cost of exercise — a legit endurance aid, best in recreational athletes.

Lower-evidence options

Taurine (C) — A conditionally-essential amino acid with broad but mostly modest effects on exercise, blood pressure, and metabolic markers. · Glycerol (C) — A hyperhydration agent that expands fluid volume for hot-weather endurance — real but niche. · Cordyceps (D) — A popular endurance mushroom whose human performance data are weak and inconsistent.

Goes with

IronGrade AEvidence grade A
Beta-AlanineGrade AEvidence grade A
CaffeineGrade AEvidence grade A
Beetroot / Dietary NitrateGrade BEvidence grade B
TaurineGrade CEvidence grade C
GlycerolGrade CEvidence grade C
CordycepsGrade DEvidence grade D

Entries that share this one's tags or conditions.

Beetroot / Dietary Nitrate for Blood pressureEvidence grade B — Modest reductionEvidence grade B
Beetroot / Dietary Nitrate for Endurance / O2 costEvidence grade B — Larger in recreational athletesEvidence grade B
Beetroot / Dietary Nitrate: dosage and how to take it6–13 mmol nitrate, 2–3 h prior.Evidence grade B
Beetroot / Dietary Nitrate: side effects, safety & interactionsSafe; harmless pink urine/stool. Additive blood-pressure lowering with antihypertensives.Evidence grade B

Sources

This entry lists no references of its own — it is assembled from the entries it links to, whose sources are on their pages.

Last revised Jul 10, 2026. A grade is this entry's reading of the evidence, not medical advice.