Written by Keely Puchalski, ND. Results from this study demonstrated that a single 400 mg dose of New Zealand pine bark extract (Enzogenol®) significantly reduced postprandial blood glucose levels in healthy adults after a 75 g sucrose challenge. Though effects were modest, reductions in blood glucose and area under the curve (iAUC) were significant compared to placebo at 90 and 120 minutes, suggesting improved glycemic responses. The 50 mg dose showed a minor but significant reduction in peak blood glucose compared to control, and no adverse events were reported in either group.

Blood sugar control is crucial for overall health, particularly in preventing and managing diabetes. Glycemic responses refer to changes in blood glucose following food intake, and maintaining these levels within a healthy range is essential for metabolic function. Poor postprandial glucose control is associated with long-term complications, including cardiovascular disease and neuropathy¹. In the United States, 2021 Centers for Disease Control and Prevention estimates report approximately 38.4 million people with diabetes and 97.6 million adults with prediabetes, placing them at increased risk for type 2 diabetes (T2D)². Globally, diabetes prevalence continues to rise, highlighting the need for effective strategies to manage blood glucose³.

Herbal and botanical interventions, such as pine bark extract rich in procyanidins, have been investigated for their potential to modulate glucose absorption and improve glycemic responses⁴. New Zealand pine bark extract (Enzogenol®) is derived from 15–30-year-old Pinus radiata trees and contains >80% proanthocyanidins, 1–2% taxifolin, other flavonoids and phenolic acids (~8%), and some carbohydrates (5–10%)⁵. Prior research by the study authors demonstrated postprandial glucose reductions following a glucose challenge in healthy adults at doses of 50 and 400 mg, supporting its potential for acute glycemic control⁶.

This acute, randomized, single-blind, crossover, placebo-controlled study evaluated the effects of 50 mg and 400 mg doses of New Zealand pine bark extract co-administered with 75 g sucrose on postprandial glucose and insulin responses. Forty healthy adults (12 male, 28 female; mean age 30.1 ± 1.3 years; BMI 23.4 ± 0.5 kg/m²; HbA1c 32.5 ± 0.6 mmol/mol; FBG 4.7 ± 0.1 mmol/L) completed the study. Participants were free from impaired glycemic control, chronic illness, and medications affecting glucose metabolism.

Each participant attended three study visits in a fasted state, receiving either:

1. Placebo (75 g sucrose only)
2. 50 mg New Zealand pine bark extract with 75 g sucrose
3. 400 mg New Zealand pine bark extract with 75 g sucrose

Visits were separated by a 48–72-hour washout period to minimize carryover effects. Blood glucose was measured via capillary finger-prick at −10, 0, 15, 30, 45, 60, 90, and 120 minutes, and plasma insulin was assessed using a chemiluminescent immunoassay. Primary outcomes included fasting and postprandial glucose and insulin, with iAUC calculated via trapezoidal rule. Secondary outcomes included peak glucose, peak insulin, 1-hour glucose, 1-hour insulin, and timing of peaks. Data were analyzed using a linear mixed model with Bonferroni post-hoc pairwise comparisons; p ≤0.05 was considered statistically significant.

Key findings:

• iAUC Glucose: 400 mg pine bark extract significantly reduced glucose iAUC by 13.8% at 90 min (p = 0.029) and 14.4% at 120 min (p = 0.037) compared to placebo.
• Peak Glucose: 50 mg significantly reduced peak glucose by 5.5% compared to placebo (p = 0.016).
• Time Points: Postprandial glucose was also lower at 45 min with 400 mg (p = 0.010) and at 90 min with 50 mg (p = 0.023) versus placebo.
• Insulin Responses: No significant differences were detected in insulin iAUC, peak insulin, or timing; only 1-hour insulin differed between 50 mg and 400 mg groups (p = 0.019).
• Glucose Curve Shape: Monophasic curves (single peak, associated with higher T2D risk) were observed in 86.8% (placebo), 83.8% (50 mg), and 66.7% (400 mg); biphasic curves (≥2 peaks) were seen in 13.2%, 13.5%, and 30.8%, respectively.

No adverse events occurred.

The study demonstrates that a single 400 mg dose of New Zealand pine bark extract modestly improves postprandial glycemic responses to sucrose in healthy adults, with subtle dose-dependent effects. Improvements in glucose may reflect enhanced postprandial control, although insulin responses were variable. Mechanistic explanations, such as sucrase inhibition or reduced glucose absorption, are speculative; this study did not directly measure these pathways.

Limitations include the single-blind design (investigators unblinded), a healthy adult sample limiting extrapolation to prediabetic or T2D populations, small sample size (n = 40), acute single-meal assessment, and variability of capillary glucose measurements. Generally, significance for glucose management is defined by a 20% or more reduction in postprandial iAUC glucose. Multiple comparisons may inflate false positives, and no mechanistic biomarkers (e.g., sucrase activity, GLP-1, GIP) were assessed.

Despite these limitations, even modest postprandial glycemia improvements may be beneficial, especially if sustained with repeated use. Future studies should assess longer-term effects on HbA1c, glycemic variability, beta-cell function, and cardiovascular risk factors in broader populations.

These findings support previous work showing positive effects of pine bark extract on glucose challenges, suggesting potential for acute glycemic support in healthy individuals, with greater potential benefit in populations at risk for T2D⁶. Longer-term studies and mechanistic investigations are warranted to clarify clinical relevance.

Source: Lim, Wen Xin Janice, Lynne Chepulis, Pamela von Hurst, Cheryl S. Gammon, and Rachel A. Page. “An acute, placebo-controlled, single-blind, crossover, dose-response, exploratory study to assess the effects of New Zealand pine bark extract (Enzogenol®) on glycaemic responses in healthy participants.” Nutrients 12, no. 2 (2020): 497.

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© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Posted October 16, 2025.

Keely Puchalski, ND, is a licensed naturopathic physician and natural products expert with a clinical focus on mental health. She earned her ND from Sonoran University of Health Sciences (formerly Southwest College of Naturopathic Medicine) in 2020. Dr. Puchalski has conducted original research in botanical medicine, with discoveries leading to multiple patents and high-impact journal publications. She has authored eight peer-reviewed papers and presented her work at national conferences, webinars, and educational events.

She is the co-founder of Restored Counseling & Wellness Center in Gilbert, AZ, where she leads a collaborative team of therapists and naturopathic doctors dedicated to integrative mental health care:  https://restoredcw.com.

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2. Prevention CfDCa. National Diabetes Statistics Report, 2024. CDC. Accessed October, 10, 2025. https://www.cdc.gov/diabetes/php/data-research/index.html
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5. Frevel MA, Pipingas A, Grigsby WJ, Frampton CM, Gilchrist NL. Production, composition and toxicology studies of Enzogenol® Pinus radiata bark extract. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. Dec 2012;50(12):4316–24. doi:10.1016/j.fct.2012.08.051
6. Lim WXJ, Chepulis L, von Hurst P, Gammon CS, Page RA. An Acute, Placebo-Controlled, Single-Blind, Crossover, Dose-Response, Exploratory Study to Assess the Effects of New Zealand Pine Bark Extract (Enzogenol(®)) on Glycaemic Responses in Healthy Participants. Nutrients. Feb 15 2020;12(2)doi:10.3390/nu12020497