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Diosmin

Also known as: Diosmin flavonoid, Nonmicronized diosmin

A phlebotonic flavonoid studied for venous symptoms; single-ingredient diosmin and micronized flavonoid mixtures are not the same intervention.

Woodcut-style amber jar and shallow dish of pale ochre powder
Editorial illustration

Diosmin is a flavonoid studied orally for chronic venous symptoms, alone or in a micronized flavonoid mixture. Class-wide evidence suggests a small reduction in leg swelling, but diosmin-specific certainty is limited. These findings do not establish ulcer healing or justify replacing assessment of a swollen leg.1, 2

  • The 2020 Cochrane review pooled several phlebotonic drugs, not just diosmin.1
  • The six-month comparison used 600 mg/day diosmin versus 900 mg/day micronized diosmin plus 100 mg/day hesperidin.2
  • An active-comparator noninferiority design does not independently establish benefit over placebo.2

What is Diosmin?

A tablet containing nonmicronized diosmin differs from micronized diosmin plus hesperidin. The active-comparator trial assessed specified preparations in adults with symptomatic chronic venous disease; it did not test ordinary citrus foods or every supplement carrying the ingredient name.2

Where it comes from

Natural sources

  • A flavonoid identity, distinct from a serving of citrus or an unspecified plant extract

How it's made

The trial describes a pure semisynthetic nonmicronized preparation and a separate micronized combination.

What it does in products

  • Ingredient in oral venous-symptom formulations and supplements

Benefits

Possible venous-symptom relief, with limited ingredient-specific certainty

limited evidence

Some symptom and swelling findings are favorable, but the most reliable pooled estimate concerns a mixed drug class.1, 2

Cochrane found modest edema benefit, little or no quality-of-life difference and no convincing ulcer-healing benefit across phlebotonics. Its authors caution that individual-drug findings are limited by small numbers and heterogeneity. The selected diosmin trial adds a formulation comparison, not a placebo estimate.

Evidence scope and limitations

Oral chronic-venous-symptom evidence, a mixed-phlebotonic review and one diosmin formulation comparison; not acute thrombosis, hemorrhoid protocols or individualized treatment.

  • Class-wide estimates are not diosmin-only effect sizes or adverse-event rates.
  • The single-blind active-comparator trial lacks placebo control and includes manufacturer-employed authors.
  • The review could not estimate medium- or long-term class safety reliably from its short studies.
  • Primary abstracts and disclosures were checked; inaccessible full-text population details are not asserted.

Evidence last checked: 2026-10-15

Side effects & safety

Gastrointestinal adverse effects and incomplete long-term safety evidence (varies)The class review found slightly more adverse events than placebo, most often gastrointestinal complaints. That pooled risk is not a precise diosmin-only incidence rate.

Safety considerations

  • The reviewed studies do not establish a complete interaction profile. FDA advises discussing supplements alongside medicines and medical conditions; do not interpret unreported interactions as proof of none.
  • Not for: These sources do not clear pregnancy, breastfeeding, children or complex comorbidity for unsupervised supplementation.
  • Not for: Do not use a symptom-focused supplement trial as a substitute for diagnosis, prescribed treatment or wound assessment.
1, 2, 4

Amounts studied & product use

These figures describe research or common product use, not a personal dose or treatment recommendation.

In supplement studies and products

One six-month trial compared 600 mg/day nonmicronized diosmin with a 1,000 mg/day mixture containing 900 mg diosmin and 100 mg hesperidin. These are study regimens, not personal dosing advice or evidence that milligram-for-milligram substitution works across preparations.

2

Regulatory status

  • FDA regulates dietary supplements under a different framework from drugs, with manufacturers responsible for safety and labeling. A supplement listing or a foreign clinical publication does not itself establish FDA drug approval for venous disease or ulcer treatment.
3

Two similar symptom curves do not answer the placebo question

In the single-blind study, the nonmicronized preparation met the authors' noninferiority criterion against the combination. There was no placebo arm; the comparison cannot isolate how much improvement reflects a specific treatment effect. Two authors reported employment by the manufacturer associated with the study.

Keep both layers visible: formulation-specific research helps interpret a label, while the broader review limits the strength of the clinical conclusion. Neither an ingredient's identity nor improvement in swelling establishes ulcer closure or long-term disease prevention.

2, 1

Frequently asked questions

Does a micronized flavonoid fraction mean pure diosmin?

Not in the cited comparison: it contained diosmin and hesperidin. The combination and pure nonmicronized ingredient should remain separate when matching evidence to a label.2

Does the edema finding prove a venous ulcer will heal?

No. Swelling and ulcer closure are separate endpoints. The class review did not establish a convincing ulcer-healing benefit, and its pooled results cannot be assigned wholesale to diosmin.1

The bottom line

Match the exact flavonoid preparation to the study, and keep modest symptom evidence separate from disease-treatment claims.

References

  1. Martinez-Zapata MJ, Vernooij RWM, Simancas-Racines D, et al.. Phlebotonics for venous insufficiency. Cochrane Database of Systematic Reviews (2020) · systematic review · PMID 33141449; DOI 10.1002/14651858.CD003229.pub4; primary abstract checked; class-wide results distinguished from diosmin
  2. Steinbruch M, Nunes C, Gama R, et al.. Is Nonmicronized Diosmin 600 mg as Effective as Micronized Diosmin 900 mg plus Hesperidin 100 mg on Chronic Venous Disease Symptoms? Results of a Noninferiority Study. International Journal of Vascular Medicine (2020) · randomized trial · PMID 32206351; DOI 10.1155/2020/4237204; primary abstract and disclosures checked; no placebo arm
  3. Dietary Supplements. U.S. Food and Drug Administration · government guidance · Undated agency resource; checked October 15, 2026
  4. Dietary Supplements: Consumer Updates. U.S. Food and Drug Administration · government guidance · Undated agency resource; medicine, condition and professional-consultation cautions checked October 15, 2026

Revision history

  1. Initial AI-assisted source checks and claim-level citation mapping under the site-authorized publishing workflow. No separate human or independent medical review is claimed.