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Moderate evidenceHeart & metabolic

Diosmin

Diosmin — usually sold as micronized purified flavonoid fraction (90% diosmin, 10% hesperidin) — has the largest trial base of any vein supplement and is a prescription medicine in much of Europe and Latin America. The evidence is most convincing for hemorrhoidal bleeding and modest for leg swelling, and most of it comes from one manufacturer.

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What the science says

  • Improves hemorrhoid symptoms, especially bleeding Moderate evidence

    The Cochrane review of phlebotonics for haemorrhoids (24 studies; 20 comparisons enrolling 2,344 participants, predominantly diosmin-based products) found significant benefit for bleeding (OR 0.12, 95% CI 0.04-0.37), pruritus (OR 0.23), discharge and leakage (OR 0.12), post-haemorrhoidectomy bleeding (OR 0.18) and overall symptom improvement (OR 15.99). Pain did not reach significance (OR 0.11, p = 0.06). The reviewers flagged methodological limitations throughout.

  • Slightly reduces leg oedema in chronic venous insufficiency Moderate evidence

    Hidrosmine and diosmine were one of the larger subgroups (11 trials) in the 2020 Cochrane phlebotonics review, which found moderate-certainty evidence of a slight reduction in lower-leg oedema (RR 0.70) and ankle circumference (-4.27 mm) versus placebo. The same review found probably no difference in quality of life (SMD -0.06) and no effect on ulcer healing (RR 0.94) — so expect a modest symptomatic effect, not a fix.

  • Micronization matters, and generic diosmin is not automatically equivalent Limited evidence

    The trial evidence is overwhelmingly for the micronized purified flavonoid fraction, where particle size below ~2 micrometres was engineered to improve absorption of a poorly soluble flavone. Supplement-grade diosmin extracted from Sophora japonica at 500-1000 mg is chemically the same molecule but not necessarily the same product; no head-to-head bioequivalence data support treating them interchangeably.

Dosage & safety

Studied doseChronic use: 500 mg micronized purified flavonoid fraction twice daily (1000 mg/day) for 2-6 months. Acute hemorrhoidal flare regimen used in trials: 3000 mg/day (two tablets three times daily) for 4 days, then 2000 mg/day for 3 days, then the maintenance dose. Supplement labels commonly list 500-1000 mg diosmin, sometimes with 100 mg hesperidin.
SafetyMostly gastrointestinal: abdominal pain, diarrhoea, nausea, dyspepsia; headache and rash occur less often. Cochrane found phlebotonics increase adverse events slightly overall (RR 1.14). Safety data beyond a few months are thin. Use in pregnancy for hemorrhoids is common practice in some countries but not well established — ask an obstetric clinician. A prescription drug in France, Russia and much of Latin America and a dietary supplement in the US, so quality and labelling vary. A substantial share of the evidence base is manufacturer-sponsored. Rectal bleeding should always be evaluated by a clinician before being self-treated as hemorrhoids — colorectal cancer presents the same way.

How to take it

TimingTwice daily for maintenance; acute hemorrhoid regimens front-load 3000 mg/day for the first four days.
With food?With meals, which reduces the abdominal pain and nausea that are the main side effects.
Worth knowingLook for micronized purified flavonoid fraction (MPFF) on the label — particle size is what the trials were done with, and plain diosmin powder is not the same product.

Frequently asked questions

Does diosmin work for hemorrhoids?

Diosmin has moderate evidence for hemorrhoids: a Cochrane review of phlebotonics, mostly diosmin-based, found significant benefit for bleeding, itching, discharge and overall symptoms. The reduction in pain was not statistically significant, and much of the evidence is manufacturer-sponsored.

How much diosmin should I take for a hemorrhoid flare?

Trials used micronized diosmin (MPFF) at 3000 mg/day for 4 days, then 2000 mg/day for 3 days, then 500 mg twice daily. Have rectal bleeding checked by a clinician before assuming it is hemorrhoids.

Does diosmin help leg swelling and varicose veins?

Diosmin has moderate evidence for only a slight reduction in leg oedema in chronic venous insufficiency, about 4.27 mm less ankle circumference in the Cochrane phlebotonics review. The same review found probably no difference in quality of life and no effect on ulcer healing.

Is plain diosmin as good as micronized diosmin (MPFF)?

Not necessarily. The trial evidence for diosmin is overwhelmingly for micronized purified flavonoid fraction, and no bioequivalence data show that plain supplement-grade diosmin performs the same. Look for MPFF on the label.

Scientific references

Where to buy

Nature's Craft, Diosmin & Hesperidin, 60 Capsules

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