Iridoid glycosides

PhytochemicalIridoidBest with a meal

What is it

Iridoid glycosides are plant-derived iridoid compounds with a sugar (usually glucose) attached. They are common in many medicinal plants including devil's claw (harpagoside), noni (deacetylasperulosidic acid), olive leaf (oleuropein), and plantain (aucubin).

Evidence for 3 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Joint pain (devil's claw, source-specific)

Good Evidence

Standardized harpagoside-containing devil's claw extracts show modest pain reductions in osteoarthritis and low back pain trials.

Cardiovascular markers (oleuropein from olive leaf)

Good Evidence

Olive leaf extracts standardized for oleuropein show modest blood pressure and lipid improvements in small trials.

Iridoid glycosides as a class

Mixed Evidence

No useful clinical evidence for 'iridoid glycosides' as a class; effects are compound- and source-specific.

How it works

After ingestion, gut bacteria hydrolyze the glycosidic bond, releasing the more lipophilic aglycone, which is then absorbed. Specific iridoid aglycones interact with anti-inflammatory pathways (NF-kB inhibition, COX modulation), have antioxidant activity, support hepatic detoxification, and in some cases modulate neurotransmitter systems. Iridoid glycosides as a class do not have unified clinical effects. The biology depends on which specific molecule, in what source plant, at what dose. Marketing of 'total iridoid glycosides' as a standardization marker for products like noni juice provides a quality benchmark but not a single mechanism.

Dosage

No RDA exists. Doses depend on the specific extract. For example, devil's claw products often target 50-100 mg/day of harpagoside. Noni juice products commonly list total iridoid content per serving but lack a consensus effective dose.

When and how to take it

Most iridoid-containing extracts are taken once or twice daily with food. Source-specific.

1 commercial form

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Source-plant standardized extract

How iridoid glycosides typically appear in supplements.

Aglycones formed by gut bacteria are absorbed; total glycoside content is a useful quality marker.

Safety

Most iridoid-rich extracts are well tolerated at typical doses. Mild GI upset is the most common side effect. Some iridoids are bitter and can irritate mucous membranes at high concentrations. Long-term safety varies by source plant.

Who should be cautious

Pregnancy, breastfeeding, and condition-specific cautions depend on the source plant. Read product-specific guidance.

Interactions

Source-dependent. Devil's claw can interact with anticoagulants; olive leaf may potentiate blood pressure medications; large noni juice intake has been associated with rare hepatotoxicity case reports. No class-wide summary applies.

Food sources

Olive products (oleuropein)

Amount
variable
%DV
—

Noni fruit (deacetylasperulosidic acid)

Amount
variable
%DV
—

Frequently asked questions

What does 'standardized to iridoid glycosides' mean?⌄

It is a quality benchmark indicating the extract contains a specified amount of these compounds. It does not by itself describe what the product is supposed to do clinically.

Are iridoid glycosides absorbed intact?⌄

Usually not. Gut bacteria typically cleave the sugar, and the aglycone is what reaches circulation.

References

Iridoid glycosides on Wikidata — Wikidata link

Iridoid glycosides on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Iridoid glycosides (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.