My evenings have completely changed
I used to be useless after 7pm. Now I have energy into the evenings and actually enjoy time with my family rather than just surviving until bedtime. Stack has genuinely changed my quality of life.
Nour M.
Back to Formulary
Mineral160mg
Calcium Citrate
BIOAVAILABLE BONE & MUSCLE SUPPORT
Dairy freeGluten freeSoy freeGMO free
$10.99/mo
30-day supply
Key Benefits
1
Supports bone density and skeletal health
2
Highly bioavailable citrate form
3
Promotes muscle contraction and nerve signaling
4
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 dose⚗️
3rd Party Tested
🩺
Doctor Formulated
🛡️
cGMP Certified
The Details
Why you'll love it
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
Clinical Evidence
Key studies supporting Calcium Citrate, from peer-reviewed journals.
1
Calcium citrate is absorbed 22-27% better than calcium carbonate
Meta-analysis of calcium bioavailability: a comparison of calcium citrate with calcium carbonate — 1999
2
Calcium supplements improve bone density in adults under 35
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
What's Inside
Third-Party Tested
Every batch is independently tested by ISO-17025 accredited labs for purity, potency, and contaminants.
Doctor Formulated
Designed by healthcare professionals using evidence-based research and clinical expertise.
cGMP Certified
Manufactured in cGMP & UL certified, FDA-registered facilities with a flawless inspection record.
Important Information
Contraindications
- hypercalcemia
- kidney stones
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
changed my whole routine tbh
used to take like 5 different supplements every morning and always forgot at least two of them. now i take one stack pack and that's it. so much simpler. and the results are actually better. wild.
Hazel B.
The value proposition is actually excellent
I calculated what I was spending on separate supplements, gym supplements, and energy drinks before Stack.
Tim A.
Simple, smart, and it actually works
The packaging is some of the nicest I've seen in wellness. But beyond aesthetics, the product delivers. My energy throughout the day is more stable and I'm recovering faster from workouts. I was genuinely skeptical.
Ashley N.
The inflammation reduction has been significant
I suffer from low-grade chronic inflammation and it affects everything - energy, mood, joint comfort. Stack's personalized formula has noticeably reduced these symptoms over three months. The targeted approach is clearly more effective than generic options.
Eric T.
My husband noticed before I did
About six weeks in my husband said I seemed more like myself - more energy in the evenings, less irritable, sleeping better. I hadn't even consciously registered how much had changed until he said it.
Amara S.
Personalized for you
Not sure if Calcium Citrate is right for you?
Take our 2-minute Health Assessment and let our AI build your personalized stack — every supplement chosen for your specific goals.
Take the Health AssessmentProduct images are for illustrative purposes and may not represent actual packaging.
