Pterostilbene for Blood Sugar Balance
Glucose-lowering effects seen in animals have not been reproduced in human trials.
Overview
Verdict
How It Works
Dosing & Protocol
Typical dose
- Recommended dose
- Studied at 50-250 mg/day for 6-8 weeks; glucose outcomes were not improved
- Expected timeframe
- Not established
Protocol
- form
- Pterostilbene, with or without grape extract
- duration
- 6-8 weeks
- co factor
- Evidence is insufficient. Preclinical work is encouraging: pterostilbene activates AMPK and PPAR-alpha, improves insulin sensitivity in diabetic rodent models, reduces hepatic glucose output and lowers blood glucose in streptozotocin-induced diabetic rats, with some studies suggesting effects comparable to metformin in those models. The human trial that examined this - a randomised, double-blind, placebo-controlled study in adults with hypercholesterolaemia - measured glucose alongside lipids and blood pressure and found no significant improvement in glycaemic parameters at 50-250 mg/day over 6-8 weeks. It did find a reduction in blood pressure and, at the higher dose, an increase in LDL cholesterol.
- titration
- Not applicable - no dose showed a glycaemic benefit
- starting dose
- Not established. The Riche trials used 50 mg twice daily, 100 mg twice daily, or 100 mg twice daily with grape extract
Evidence
What the studies say
Pterostilbene on Metabolic Parameters: A Randomized, Double-Blind, and Placebo-Controlled Trial
Riche DM, McEwen CL, Riche KD +4 more
Pterostilbene 125 mg twice daily reduced systolic and diastolic blood pressure, but LDL cholesterol rose in the high-dose monotherapy group.
Safety
Caveats
The rodent-to-human gap is the story here: impressive glucose lowering in diabetic rats, nothing measurable in the human trial. For blood sugar, the evidence sits with dietary change, weight loss - which can put type 2 diabetes into remission - physical activity, metformin, SGLT2 inhibitors and GLP-1 receptor agonists. Prediabetes responds well to structured lifestyle programmes. Do not delay diagnosis or treatment: symptoms of thirst, frequent urination, unexplained weight loss, blurred vision or recurrent infections need testing, and unexplained weight loss with new diabetes in an older adult warrants investigation. Safety of pterostilbene: the notable finding is that 250 mg/day raised LDL cholesterol in that same trial - a concern in a population already at cardiovascular risk. Human safety data extend to about 8 weeks only, long-term safety is unknown, and no upper intake level exists. Pterostilbene inhibits CYP enzymes in vitro and may have antiplatelet effects, so use caution with anticoagulants, antiplatelet drugs and narrow-therapeutic-index medication, and stop before surgery. It also lowered blood pressure modestly, so monitor if taking antihypertensives. Avoid in pregnancy and breastfeeding, as no safety data exist, and gestational diabetes requires specialist management.
Less likely to help if
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