My name is Manoel. I'm 52 from Brazil. For years I dealt with brittle, yellow toenails that cracked easily.I tried drugstore creams and tea tree oil. Nothing lasted. My podiatrist said the issue might be internal, not just on the surface.Researching, I found the concept of a "nano probiotic" for nail support from the US. I'm not a doctor and this is not medical advice. This is just my personal experience.I decided to test one called NanoDefensePro for 90 days. Here's what I noticed:Week 2: Nails looked slightly less yellow.Day 30: They felt stronger. Less breaking when I clipped them.Day 90: I feel more confident. The constant brittleness seems to have improved.Important Disclosure: I am an affiliate for this product. If you buy through my link, I may earn a commission at no extra cost to you. I am not a medical professional. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your doctor.