KCC—January 6, 2026
This stuff is THE TRUTH! I don't often leave reviews unless I'm seriously blown away by a product or it's shockingly bad lol. I suffer from iron deficiency anemia and had been rehabilitating my once indestructible nails. With this product they're finally getting back to their former glory. Not only does it keep my nails strong but flexible, I find that it keeps my polish on for 14+ DAYS when used as a base coat. After a polish change, I oil my bare nails consistently for a day or so (I like hard as hoof and bliss kiss nail oil or cnd solar, but any deeply penetrating oil should work). Before my next polish change, I moisturize my hands and nails thoroughly, wash my hands with dawn dishsoap to dehydrate and remove the excess oils from nails. Then, I typically apply 2 coats of this as base polish, let dry, followed by two coats of color and a fast dry top coat. It's been several months without any nail breaks! Read more
Jessica Sierra—December 22, 2025
Excellent product. Since I started using this hardener my nails are stronger and no longer break easily. It is easily applied and dries quickly. Highly recommended. Read more
Gabrielle Bove—September 9, 2024
So I was desperate because my nails were very thin from acrylics which usually i never have that problem but it was overfilling that hurt them. Anyways when i soaked off my acrylics 2 of my nails split in half as you can see. I had a nail girl tell me that will take months to grow back and i was so upset. I found this product and its been about 2 weeks so actually and its working amazing. I am so happy and thankful I gave it a try. Obviously its not completely healed but it is a lot smaller of a split then it was before i used this. The photo on the left and the left nail is from Aug 26th and then the middle one is the beginning of Sept and the last one on the right was from yesterday. Big difference ! And the right photo is basically the same. The left nail is from Aug 26th and the right one is from yesterday. Still a working process which i knew it wasn't gonna be that fast because of the condition of my nails. I just wanted to show my progress so far. Update 8/24- This is what my nails are looking like now. I can't believe the results Read more
MtnMomma—July 18, 2025
This stuff is amazing! My nails were getting very thin from my stylist filing down my nails too much to get the dip and gel off. I just bought this on Prime Day (just over a week ago) and I can already notice a difference. My nails that were thin, are definitely stronger. My nails are growing out faster and where they are growing in, they are thicker than before as well. If you decide to give your nails a break from gel/dip, definitely look into getting this for that break. If you just use this, it will flake off around 3 days in but that's because your nail essentially sucked out all of the good stuff on the bad parts of your nail. I was amazed to see the difference it made. Read more
H.R.—June 3, 2024
I’m extremely rough on my hands - typing for work during the day, washing veggies and fruits for fresh juice and dishes on the daily with no gloves, and ranch life in the evenings (think scrubbing down horses, throwing around hay bales, scrubbing water troughs, getting down and dirty when things get crazy). I have never been able to grow my nails past the tips of my fingers and the few times I did, they broke within a day or two. My nails have not broken once since using the Biotin Ultra Strength!! Yes it’s more like a polish than an oil. Yes if you’re really rough the polish will chip off a bit - no big deal for me just clean it off with acetone and re-apply. I’ve been using it for about 2 weeks and the difference is crazy. My nails are growing and strong, and I’m only using 1 coat every few days when it starts to chip. I’ve not been doing the 3 coats per application as other comments have suggested, just the one coat and I wait for it to chip before taking it off and re-applying. Highly recommend if you’re trying to get your nails longer and stronger!! No more manicures for me! Read more

Coco—July 26, 2025
I’ve been using this nail treatment for a few weeks. It goes on smoothly and dries fairly quickly, which is great. It gives my nails a nice clear shine and a slightly stronger feel. However, I haven’t noticed a significant improvement in nail growth or reduction in breakage. It might work better with longer use, but for the price, I was expecting more visible results. Read more
Debbie Springer—November 17, 2025
Worth every penny! I’m growing nails! For decades I’ve had thin, cracked and easily broken nails, as I have thyroid and autoimmune issues. These problems can really mess up nails, so for years I’ve paid to have acrylic nails by professional manicurists. Now that we are retired and traveling full time in our RV, I needed to do my own nails, which means growing them. They’re now at the tips of my fingers, and a few are longer! I’m so excited, so I took a picture. I’m still practicing my nail polish skills…. lol Read more
Ginger—January 11, 2026
Love thus it does what it says, My nails look very good and are strong Read more