Blood pressure: what the evidence supports

14 graded interventions for blood pressure, ranked by strength of evidence.

Overall grade: Grade B
Last revised: Jul 10, 2026; 14
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.

6 at grade B · 8 at grade C — 14 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
Magnesium~2–3 mmHg in meta-analysis	Evidence grade B	Small	high
PotassiumEspecially salt-sensitive/hypertensive	Evidence grade B	Moderate	high
L-CitrullineModest reduction	Evidence grade B	Small	mixed
Beetroot / Dietary NitrateModest reduction	Evidence grade B	Small	high
Cocoa FlavanolsModest reduction	Evidence grade B	Small	high
HibiscusSeveral mmHg	Evidence grade B	Moderate	high
TaurineMinor reduction	Evidence grade C	Small	mixed
QuercetinHigher doses	Evidence grade C	Small	mixed
L-ArginineModest reduction	Evidence grade C	Small	mixed
Olive Leaf ExtractModest	Evidence grade C	Small	mixed
Pycnogenol (Pine Bark)Modest	Evidence grade C	Small	mixed
Grape Seed ExtractModest	Evidence grade C	Small	mixed
NattokinaseModest	Evidence grade C	Small	mixed
Black Seed Oil (Nigella sativa)Modest	Evidence grade C	Small	mixed

MagnesiumEvidence grade B
~2–3 mmHg in meta-analysis
Smallhigh
PotassiumEvidence grade B
Especially salt-sensitive/hypertensive
Moderatehigh
L-CitrullineEvidence grade B
Modest reduction
Smallmixed
Beetroot / Dietary NitrateEvidence grade B
Modest reduction
Smallhigh
Cocoa FlavanolsEvidence grade B
Modest reduction
Smallhigh
HibiscusEvidence grade B
Several mmHg
Moderatehigh
TaurineEvidence grade C
Minor reduction
Smallmixed
QuercetinEvidence grade C
Higher doses
Smallmixed
L-ArginineEvidence grade C
Modest reduction
Smallmixed
Olive Leaf ExtractEvidence grade C
Modest
Smallmixed
Pycnogenol (Pine Bark)Evidence grade C
Modest
Smallmixed
Grape Seed ExtractEvidence grade C
Modest
Smallmixed
NattokinaseEvidence grade C
Modest
Smallmixed
Black Seed Oil (Nigella sativa)Evidence grade C
Modest
Smallmixed

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); Quercetin (grade C); L-Arginine (grade C); Olive Leaf Extract (grade C); Pycnogenol (Pine Bark) (grade C); Grape Seed Extract (grade C); Nattokinase (grade C); Black Seed Oil (Nigella sativa) (grade C).
Studies disagree: L-Citrulline (mixed agreement).

The evidence in words

The evidence map

This is the ranked evidence for blood pressure: every compound in the knowledge base with a graded effect, best-supported first. Grades reflect replication and effect size, not popularity or marketing.

Best-supported

Magnesium (grade B) — ~2–3 mmHg in meta-analysis · Potassium (grade B) — Especially salt-sensitive/hypertensive · L-Citrulline (grade B) — Modest reduction · Beetroot / Dietary Nitrate (grade B) — Modest reduction · Cocoa Flavanols (grade B) — Modest reduction · Hibiscus (grade B) — Several mmHg

Weaker or unproven

Taurine (grade C) — Minor reduction · Quercetin (grade C) — Higher doses · L-Arginine (grade C) — Modest reduction · Olive Leaf Extract (grade C) — Modest · Pycnogenol (Pine Bark) (grade C) — Modest · Grape Seed Extract (grade C) — Modest · Nattokinase (grade C) — Modest · Black Seed Oil (Nigella sativa) (grade C) — Modest

Goes with

MagnesiumGrade BEvidence grade B
PotassiumGrade BEvidence grade B
L-CitrullineGrade BEvidence grade B
Beetroot / Dietary NitrateGrade BEvidence grade B
Cocoa FlavanolsGrade BEvidence grade B
HibiscusGrade BEvidence grade B
TaurineGrade CEvidence grade C
QuercetinGrade CEvidence grade C

Entries that share this one's tags or conditions.

Allergic rhinitis: what the evidence supports3 graded interventions for allergic rhinitis, ranked by strength of evidence.Evidence grade B
Antibiotic-associated diarrhea: what the evidence supports2 graded interventions for antibiotic-associated diarrhea, ranked by strength of evidence.Evidence grade B
Anxiety: what the evidence supports6 graded interventions for anxiety, ranked by strength of evidence.Evidence grade B
Beetroot / Dietary Nitrate for Blood pressureEvidence grade B — Modest reductionEvidence 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.