The efficacy and safety of concentrated herbal extract granules, YH1, as an add-on medication in poorly controlled type 2 diabetes: A randomized, double-blind, placebo-controlled pilot trial

Background In Asian countries, many patients with type 2 diabetes fail to achieve controlled glycated hemoglobin (HbA_1c) levels while taking several classes of oral hypoglycemic agents (OHAs). Traditional Chinese medicine could be an alternative therapeutic option for poorly controlled type 2 diabetes. YH1 is a concentrated Chinese herbal extract formula that combines Rhizoma Coptidis and Shen-Ling-Bai-Zhu-San. This randomized, double-blind, placebo-controlled pilot study evaluated YH1 as an add-on medication for poorly controlled type 2 diabetes. Methods Forty-six patients with poorly controlled type 2 diabetes were randomly assigned 1:1 to the YH1 or placebo group. Before the trial, all subjects had received three or more classes of OHAs with HbA_1c > 7.0% (53 mmol/mol) and a body mass index 23 kg/m². During the 12-week trial, participants continued to take OHAs without any dose or medication changes. The primary endpoint was the percentage change in HbA_1c level. Per-protocol analysis was applied to the final evaluation. Results At week 12, there was an 11.1% reduction in HbA_1c from baseline and a 68.9% increase in homeostatic model assessment (HOMA) of β cell function in the YH1 group, which also exhibited significant reductions in two-hour postprandial glucose (-26.2%), triglycerides (-29.5%), total cholesterol (-21.6%), low-density lipoprotein cholesterol (-17.4%), body weight (-0.5%), and waist circumference (-1.1%). The changes in fasting plasma glucose, HOMA insulin resistance and symptom scores were not significantly different between the YH1 and placebo groups. No serious adverse events occurred during this clinical trial. Conclusions This pilot study indicates that YH1 together with OHAs can improve hypoglycemic action and β-cell function in overweight/obese patients with poorly controlled type 2 diabetes. YH1 is a safe add-on medication for OHAs and has beneficial effects on weight control and lipid metabolism. A larger study population with longer treatment and follow-up periods is required for further verification.