ENERGY, NERVES & RED BLOOD CELLS
30-day supply
Key Benefits
Essential for red blood cell formation
Supports energy metabolism and reduces fatigue
Promotes nervous system health and myelin production
Supports cognitive function and mood
Recommended Dose
1,000mcg methylcobalamin
Take one 1,000mcg capsule daily. B12 can be taken with or without food, though absorption from supplements is generally high regardless of timing. For those with known deficiency, higher doses may be recommended by a healthcare provider.
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The Details
B12 deficiency is one of the most common and underdiagnosed nutritional deficiencies in the world. It affects an estimated 6% of adults under 60 and up to 20% of those over 60, with even higher rates among vegetarians and vegans (since B12 is found almost exclusively in animal products). The symptoms creep up slowly: fatigue, brain fog, mood changes, tingling in the hands and feet — often attributed to "just getting older."
B12 is essential for producing red blood cells that carry oxygen throughout your body. Without enough B12, you produce fewer (and abnormally large) red blood cells, leading to megaloblastic anemia and the persistent fatigue that comes with it. It's also critical for myelin production — the protective sheath around your nerves that ensures rapid, accurate signal transmission.
We use Methylcobalamin, the active form of B12 that your body can use immediately. Standard supplements often use cyanocobalamin, which must be converted to methylcobalamin before your body can use it — a process that doesn't work efficiently for everyone. At 1,000mcg, this provides a meaningful dose that supports optimal levels even in those with absorption challenges.
Research
Key studies supporting Vitamin B12, from peer-reviewed journals.
A comprehensive review and meta-regression analysis of randomized controlled trials examining the impact of vitamin B12 supplementation on homocysteine levels — 2023
Efficacy of different routes of vitamin B12 supplementation for the treatment of patients with vitamin B12 deficiency: a systematic review and network meta-analysis — 2024
Study titles are simplified for readability. Provided for informational purposes — not medical advice.
Transparency
Every batch is independently tested by ISO-17025 accredited labs for purity, potency, and contaminants.
Designed by healthcare professionals using evidence-based research and clinical expertise.
Manufactured in cGMP & UL certified, FDA-registered facilities with a flawless inspection record.
As with any natural health product, consult your healthcare practitioner. Store in a cool, dry place. Keep out of reach of children. Discontinue use immediately if you experience an adverse event.
What people say
Really good supplement brand. The daily pack format is so convenient and I've been 100% consistent because of it. The quiz was genuinely thorough. Knocked one star off because I'd love the option to add or remove individual supplements as I learn more about my body.
I've tried so many supplements and honestly nothing has worked like this. The quiz is actually thorough and the results show it. Energy is UP, recovery is UP, sleep is SO much better. Can't believe it took me this long to find this brand.
Three weeks in and I already feel the difference. My morning energy is COMPLETELY different. No more dragging myself out of bed. The personalization through the quiz is what makes it work — it's not just a generic multivitamin. Stack actually thought about what MY body needs.
I've been on a health optimization journey for about three years and have tried what feels like every supplement brand on the market. Most of them are either generic multivitamins dressed up in pretty packaging, or they're so specific that you need to be a nutritionist to understand what you're actually taking. Stack sits in a completely different category. The quiz is the first thing that impressed me. It asks genuinely intelligent questions — not just 'how old are you and what's your gender' but questions about your diet, your sleep patterns, your stress levels, your exercise frequency. It felt like a real consultation rather than a data collection exercise. The pack that arrived was clearly personalized to my answers. After six weeks, the improvements have been consistent and measurable: better sleep quality, more stable energy throughout the day, and noticeably faster recovery after my runs. My partner commented that I seemed more 'on' in the evenings rather than crashing after dinner. The daily pack format is brilliant for compliance — I've been 100% consistent because the habit is so frictionless. One pack, done, every morning. No bottles, no measuring, no forgetting half of them. Genuinely one of the best health investments I've made.
My focus at work has been sharper and I'm waking up without that groggy feeling I used to have every morning. Told two friends about Stack already. Customer support was also really helpful when I had a question about one of the ingredients.
honestly wasn't sure about it at first but three weeks in and i'm so glad i tried it. energy is way better, i'm sleeping properly for the first time in months. the quiz was really detailed which gave me confidence it was actually personalized. would 100% recommend.
Personalized for you
Take our 2-minute Health Assessment and let our AI build your personalized stack — every supplement chosen for your specific goals.
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