BIOAVAILABLE BONE & MUSCLE SUPPORT
30-day supply
Key Benefits
Supports bone density and skeletal health
Highly bioavailable citrate form
Promotes muscle contraction and nerve signaling
Supports cardiovascular rhythm regulation
Wellness Goals
Recommended Dose
160mg
Take one 250mg capsule daily. Calcium absorption is most efficient in doses of 500mg or less, so this dose is optimized for bioavailability. Take at a different time than iron or zinc supplements, as they compete for absorption.
Get your personalized dose3rd Party Tested
Doctor Formulated
cGMP Certified
The Details
Your skeleton isn't a static structure — it's constantly being remodeled, with old bone being broken down and new bone being built. This process requires a steady supply of calcium, and if your dietary intake falls short, your body pulls calcium from your bones to maintain the blood calcium levels that your heart and nerves need to function.
We chose the citrate form for a reason: it's approximately 20% more bioavailable than calcium carbonate (the most common and cheapest form), and it doesn't require stomach acid for absorption. This makes it ideal for anyone over 50 (when stomach acid production naturally declines), anyone taking acid-reducing medications, and anyone who prefers the flexibility of taking it with or without food.
Calcium works synergistically with vitamin D (which enhances its absorption) and vitamin K2 (which directs it into bones rather than soft tissues). If you supplement calcium, you should also ensure adequate D and K2 intake — which is why our D Complex pairs perfectly with this.
Research
Key studies supporting Calcium Citrate, from peer-reviewed journals.
Meta-analysis of calcium bioavailability: a comparison of calcium citrate with calcium carbonate — 1999
The effect of calcium supplementation in people under 35 years old: a systematic review and meta-analysis — 2022
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.
Important Information
Contraindications
Those with hypercalcemia, kidney stones, or hyperparathyroidism should consult their healthcare provider before use.
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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