Biotin - Don't Overdo It

I honestly don’t even remember when I started taking biotin, it was sometime after my Hashimoto’s diagnosis, over ten years ago now. My fingernails were the first to tip me off—brittle, full of ridges, cracking for no reason. I think it was around the time I noticed way more hair than usual showing up in the vacuum cleaner and clogging the shower drain. That’s when I reached for one of those soft, chewy biotin supplements near the checkout at Costco (you know what I am talking about - pink and irresistible bottles on the end cap). They tasted like candy and made me feel like I was eating something tasty to remind me to keep my lush locks.

Eventually, I switched to the 5000 mcg sublingual tablets from Trader Joe’s. Easy. Convenient. In hindsight, probably too convenient.

Not long after that, the nail on my left thumb started splitting. Constantly open and snagging on fabric (cringe). All of my nails stopped growing. At one point, I forgot the bottle of biotin at my cabin and just stopped taking it for a while. That little accident turned out to be divine intervention.

A few weeks went by. My thumbnail was not splitting. Around the same time, I also noticed that my daily multivitamin was loaded with extra biotin too. Also over the recommended daily amount. I had unwittingly been taking 6000 mcg a day.

That got me curious. I did a quick Google search and it confirmed what my body was telling me: too much biotin can have the opposite effect, causing brittle nails and thinning hair. On top of that I discovered it will interfere with thyroid labs, B and D vitamin levels, and even skew some other important test results. I was messing up my bloodwork without even knowing it. My hair was still thinning, my nails were still brittle, and now I’m wondering if all that biotin might’ve been contributing to my insomnia too.

If you’re taking biotin for hair or nails, especially at high doses, it might be worth a second look. Sometimes more isn’t better. Sometimes your body’s trying to tell you it’s had enough.

Want to read more about biotin use and overuse? Click here for a simple overview of biotin side effects from the Cleveland Clinic.