This study investigates the optimal dose of fermented deglycyrrhizinated licorice (FDGL) that maximizes both safety and efficacy in managing diabetic neuropathy complications in adults. The study is a single-center, double-blind, parallel, placebo-controlled randomized clinical trial where patients with diabetic neuropathy are randomized to receive placebo, 400 mg, 800 mg, 1000 mg, or 1200 mg daily doses of FDGL for three months. The primary objective is to determine the percentage improvement of diabetic neuropathy presentations and pain scores at three months relative to baseline.

This is a single-center, double-blinded, parallel, randomized clinical trial conducted at Al-Hussein University Hospital, Cairo, Egypt. Eligible patients are randomized to receive either placebo, 400 mg, 800 mg, 1000 mg, or 1200 mg daily FDGL doses in a 1:1:1:1:1 ratio using block randomization with a block size of 5. The study employs computer-assisted random number generation for treatment allocation. Both patients and nurses are blinded to treatment allocation, with assignments kept in sealed envelopes opened only at enrollment. The study duration is 3 months with follow-up assessments at 1, 2, and 3 months.

Inclusion Criteria:

• Adult patients aged between 18 and 70 years
• Documented history of type I or type II diabetes mellitus
• Confirmed diagnosis of at least one diabetes-related complication, including peripheral neuropathy
• Diagnosis of peripheral neuropathy confirmed in both lower extremities
• Numeric rating scores (VAS) on 0 to 10 scale ≥ 4 for at least 6 months in feet/legs
• Ability to provide written informed consent
• If using concurrent therapies for diabetic neuropathy (pregabalin, gabapentin, or duloxetine), must be on stable doses for at least 3 months prior to study start

Exclusion Criteria:

• Concomitant chronic kidney disease

• Hepatic impairment

• Heart failure

• Cancer

• Major psychiatric disorders

• Pregnancy

• Refusal to sign informed consent

• Use of non-pharmacologic management strategies for diabetic neuropathy including:

  • TENS (Transcutaneous Electrical Nerve Stimulation)
  • Nerve block procedures
  • Acupuncture
  • Laser therapy