Vitamin B12 Megadose (true story)

What happens when you megadose vitamin B12? A real client case study showing the blood work, the symptoms to watch for, and what every nutrition coach should ask their clients about supplements.

2-Tips

By Jennifer Broxterman, RD

Kind Nerd Note: When a client tells you they're taking a supplement, ask to see the label, not just the name. The ingredient matters, but the dose is where things go sideways.
 

Tip #1:
45 Years of Vitamin B12 in 90 Days

My client was mega-dosing on vitamin B12, had no idea, and in just 90 days he's already exposed himself to 45+ years worth of B12. Let me back up and explain how he got into this mess.

He's on a GLP-1 and started taking a testosterone support supplement someone recommended to him, one capsule a day. When I pulled up the label, that one pill had 400 micrograms of B12, which is 16,666% of his daily requirement, or about 167 days worth of B12 in a single capsule. ⁣

For reference, the daily requirement for vitamin B12 is 2.4 mcg.

So for every two days he took it, his body got nearly a full year's worth of B12. Ninety pills in, that's around 45 years’ worth. 

His blood work backed it up. He came in nearly 700 units above the top of the normal range for vitamin B12.⁣

At doses like this, B12 isn't just "extra" and harmless. It shows up as skin rashes and acne, nerve symptoms like tingling and restlessness, insomnia, GI upset, and in rare cases, optic nerve damage. ⁣

The lesson for us as nutrition coaches: simply asking "what supplements are you taking?" isn't enough anymore. Ask to see the label. ⁣

I also asked who recommended this supplement to him… turns out, it was a gym buddy.⁣

A lot of these all-in-one and hormone support stacks are dosed way more aggressively than clients, or whoever recommended them, ever realize. Good nutrition coaching catches those mistakes.

And if you’re wondering, how did I know how much vitamin B12 is the right amount for him to be taking? 

Well, I made a nutrition coaching cheat sheet to quickly look up the recommended doses and upper limits for all the major vitamins and minerals, and I give it away for free inside my Liftoff Nutrition Masterclass.

You can grab the vitamins cheat sheet here (inside unit 3 of Liftoff).

Tip #2:
Naive vs. Expert View on Supplements

The naive view of vitamins is that if some is good, more must be better. 

The expert view is that whole foods come first, supplements are there to fill the gaps an imperfect diet leaves, and the goal is the right amount, not the max amount.

Stay kind + nerdy,   

❤️🐻🌈

Jen Broxterman
Registered Dietitian
Prosper Nutrition Coaching

Thanks for reading. Here are a few additional ways I might be able to help you.

Free
Free Stuff: All Prosper Freebies
Podcast: Podcast Shows
Masterclass: Liftoff Course

Paid
Mini-Course: Accelerator Program
Certification: Nutrition Coaching Certification
  

Jennifer Broxterman, MSc, RD

REGISTERED DIETITIAN & SPORTS NUTRITIONIST
• Award-winning Foods & Nutrition University Professor
• Successful entrepreneur of owner of NutritionRx
• 16 year CrossFit affiliate owner with my husband
• Founder of Prosper Nutrition Coaching & lead nutrition coach