Guggulsterone
Guggulsterone is a plant sterol from the guggul tree (Commiphora mukul) sold in fat-loss and cholesterol supplements. It is a bile-acid receptor (FXR) antagonist with claimed thyroid-stimulating and lipid-lowering effects, though controlled human trials have been largely disappointing.
01 Overview
Guggulsterone comes from guggul resin, long used in Ayurvedic medicine for lipid disorders. It antagonises the farnesoid X receptor and modulates bile-acid metabolism, and is popularly marketed as a thyroid and thermogenic support ingredient in cutting stacks.
While early open studies suggested cholesterol lowering, well-controlled trials in Western populations found little benefit and sometimes raised LDL, and the thyroid-boosting claim rests mainly on rodent data. It remains a widely sold but weakly evidenced supplement.
02 Mechanism
Antagonises the farnesoid X receptor (FXR), altering bile-acid and cholesterol handling; rodent data suggest increased conversion of T4 to T3, the basis of the thyroid-support claim.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Supplement | 25–75 mg/day | Oral | Standardised guggulsterones, divided doses |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Possible cholesterol loweringClaimed lipid lowering not confirmed in controlled Western trials. | Disputed | ||
| Claimed thyroid supportRodent data suggest enhanced T4-to-T3 conversion; unconfirmed in humans. | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Gastrointestinal upsetNausea, loose stools and abdominal discomfort. | Mild | Common | Clinical | |
| Skin rash / hypersensitivityRash and hypersensitivity reactions reported in trials. | Mild | Uncommon | Clinical |