This study looks at how Vitamin D3 affects brain waves in male Parkinson's disease (PD) patients who have low vitamin D, known as hypovitaminosis D. Participants will take Vitamin D3 supplements for 8 weeks, with a dosage of 50,000 IU each week. The study involves checking blood levels of Vitamin D and recording brain wave activity using a special test called quantitative electroencephalogram (qEEG) before and after taking the supplements. The qEEG measures electrical activity in the brain and can show changes in brain wave patterns.

• 8-week study: Participants will take Vitamin D3 once a week for 8 weeks.
• 2 visits needed: Participants must visit the medical university twice, once at the start and once after 8 weeks.
• No compensation: There is no mention of payment for participating in the study.

Participants must be male, aged 51-70, with PD up to stage 3, and have a body mass index (BMI) of 18.5-24.9. They should not already be taking Vitamin D3 or have certain health conditions like epilepsy, heart problems, or severe mental illnesses. Smokers and those using certain medications are also excluded. The study will be conducted in Dhaka, between March 2025 and February 2026.