October 26, 2026 · Assay Supply Co.

Did You Know? Supplements Work in Teams

Did you know nutrients rarely work alone? Your body isn't a row of separate machines — it's one crew, and the crew members cover for each other. That's the entire idea behind a stack: instead of a bathroom cabinet full of random bottles bought on random Tuesdays, you take a small set of things that were chosen to work together.

Exhibit A: magnesium and vitamin D are coworkers

Here's a connection most labels never mention: magnesium affects levels of the active form of vitamin D — the enzymes that activate it depend on magnesium. So the classic pair — D3 with K2 handling calcium (D3 helps you absorb it, K2 helps direct it) — quietly relies on magnesium in the background, doing its 300 other jobs at the same time. That's not marketing poetry; it's why these three ended up in one stack.

The other problem a stack solves: clocks

Did you know the bottles in most routines run out on different schedules? Our magnesium bottle is a 30-day supply. Our D3 + K2 bottle, at one capsule a day, is a 60-day supply. Buy them separately and you're reordering something every month, out of sync, forever.

So we built the box around the clocks. The Foundational 60-Day Box is two magnesium bottles plus one D3 + K2 bottle — everything lands together, runs out together, every 60 days.

The math, plainly

$70.90, shipping included. Standard shipping is free on the Box — no shipping line waiting at checkout (tax applies where required). The same three bottles bought separately run $83.70, plus shipping. Spread over the 60 days, it's about $1.18 a day — less than the coffee most of us reading this already bought today.

Prefer to start smaller? The Foundational Stack pairs one bottle of each for $49.90. Same team, shorter clock.

Sources

Uwitonze AM, Razzaque MS — Role of Magnesium in Vitamin D Activation and Function, Journal of Osteopathic Medicine, 2018 (the enzymes that activate vitamin D are magnesium-dependent).
National Institutes of Health, Office of Dietary Supplements — Magnesium and Vitamin D fact sheets.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Related report