A 25-hydroxy vitamin D level of 6.8 ng/mL is very low, so treatment is necessary to correct the deficiency. Calcispray 60 MD once daily is generally safe for adults and is effective in restoring vitamin D levels when taken as prescribed by your doctor. Since you have no other health issues, it should help improve your general weakness and overall energy over time. Make sure to take the spray exactly as directed, avoid exceeding the recommended dose, and follow up with your doctor for a repeat blood test after a few weeks to monitor your vitamin D levels and adjust treatment if needed. Additionally, maintaining adequate sunlight exposure and a balanced diet can help support vitamin D levels.