Outcome
Fasting Plasma Glucose
Fasting glucose, measured after 8+ hours without food. What the ingredient trials actually moved, and by how much.
Fasting plasma glucose is the concentration of glucose in blood after at least eight hours without food. It is one of the two values used to diagnose and monitor type 2 diabetes, and it is the endpoint most supplement trials report first.
What the published trials moved
| Ingredient | Effect | 95% CI | Trials | Grade |
|---|---|---|---|---|
| Berberine | −0.54 mmol/L | −0.77 to −0.30 | 28 trials, 2,313 people | B |
| Soluble fibre | not established for this endpoint | interval crosses zero | — | C |
Only berberine has a pooled estimate here that excludes no effect. That is a narrow statement and worth being precise about: it means one ingredient, in diagnosed populations, produced a change the data support. It does not mean most blood-sugar ingredients do.
How to read the size of −0.54 mmol/L
Context matters more than the decimal. A fasting glucose of 7.0 mmol/L is the diagnostic threshold for diabetes; 6.1–6.9 mmol/L is impaired fasting glucose. A reduction of 0.54 mmol/L is meaningful but will not move someone across those thresholds on its own.
That arithmetic is why the berberine dosage article leads with the milligram figure rather than the verdict. A pooled effect measured at 0.9–1.5 g per day cannot be assumed for a product printing 500 mg with no absorption strategy.
Why the interval matters more than the average
Every row above reports a confidence interval, and the difference between one that excludes zero and one that crosses it is the difference between a finding and a non-finding. “Showed a trend toward improvement” almost always describes an interval that crosses zero. The grading rule applied here is published on how we grade evidence.
What this endpoint does not tell you
Fasting glucose is a snapshot. It does not capture post-meal excursions, and two people with the same fasting value can have very different responses to a meal. Post-meal glucose is the other half, and the trials do not always agree across the two.
It also does not capture anything a reader feels. A 0.54 mmol/L change is invisible without a meter, which is why the comparison article treats the numbers and the experience as separate questions.