GLP-1 receptor agonists + Berberine contraindicated?

[Nathanologist]

I am thinking of researching a combination of Retatrutide 8mg weekly and Berberine 1500mg daily. My RS has concerns about potential for hypoglycemic interactions. Do any of you have experience with this combination or something similar to share? TIA.

Scholarly articles about the positive outcomes from 900-1500mg Berberine daily:

1. https://pmc.ncbi.nlm.nih.gov/articles/PMC2410097/ — Pilot RCT (type 2 diabetes): berberine (1.5 g/day) lowered fasting glucose, post-meal glucose, and HbA1c similarly to metformin and improved lipids; GI side effects were common but transient.
2. https://pubmed.ncbi.nlm.nih.gov/15531889/ — Nat Med 2004 (hypercholesterolemia): 3 months oral berberine reduced total cholesterol ~29%, triglycerides ~35%, and LDL ~25% in humans and upregulated LDL receptor expression in liver cells/animals.
3. https://pubmed.ncbi.nlm.nih.gov/23118793/ — Systematic review & meta-analysis (type 2 diabetes): pooled RCTs show berberine significantly lowers fasting glucose, HbA1c, and improves lipids versus control, supporting its glucose- and lipid-lowering effects.
4. https://www.frontiersin.org/articles/10.3389/fphar.2022.1015045/full — Systematic review & meta-analysis (2022): berberine consistently reduces fasting glucose, HbA1c, triglycerides and LDL; authors note heterogeneity between trials and recommend larger high-quality studies.
5. https://pubmed.ncbi.nlm.nih.gov/37522683/ — RCT of a phytosome (enhanced-absorption) berberine in overweight people with impaired fasting glucose: the phytosome formula (550 mg ×2/day) improved fasting glucose, insulin, lipids and reduced visceral fat versus placebo over ~60 days.
6. https://www.mdpi.com/1999-4923/15/11/2567 — Pharmacokinetic study of a new berberine formulation: the micellar/liposomal-style formulation raised plasma berberine AUC ~6–10× versus unformulated berberine in healthy volunteers, improving absorption and tolerability.
7. https://pubmed.ncbi.nlm.nih.gov/38016844/ — Umbrella meta-analysis of RCTs: across multiple meta-analyses, berberine improves glycemic control and reduces inflammatory biomarkers in metabolic disorders, reinforcing consistent metabolic benefits.
8. https://pubmed.ncbi.nlm.nih.gov/36467075/ — 2022 meta-analysis (type 2 diabetes): berberine significantly lowers fasting glucose, HbA1c and improves lipid profiles; authors highlight short trial durations and call for longer, larger RCTs.