Hi, roughness, yellowish nails, and vertical lines can happen due to multiple reasons such as nutritional deficiencies, dehydration, low protein intake, poor gut health, stress, anemia,
vitamin/mineral deficiencies (especially Iron, Biotin,
Vitamin B12, Zinc), or sometimes even fungal infections and
thyroid-related issues.
Before starting any supplements, I would recommend understanding the root cause first. In many cases, improving daily nutrition, protein intake, hydration, gut health, and correcting deficiencies through a balanced diet can help improve nail health naturally.
Next Steps
I would suggest a detailed nutritional assessment along with a few basic blood tests if required, so that the right guidance can be given instead of taking random supplements. Once I understand your eating pattern and lifestyle, I can help you with a personalized diet plan and suitable nutritional support accordingly.