Subscription
Every 60 days
One tub, delivered on rhythm. The way the ritual is meant to be kept.
- 60 servings · 5g Creapure®
- Free carbon-neutral shipping
- Skip, pause, cancel any time
$42
per tub · $0.70 per day
清界 · Mind, Body, Health
Strength,
for the long life.
We make the purest creatine monohydrate for mind, muscle, and metabolism — one clinically-dosed serving, every morning.
01 — Creatine Monohydrate
The Stakes
After thirty, you lose 3–8% of muscle each decade.
Strength is not a phase of life. It is the quiet architecture that carries you through it. What you protect today, you keep.
The Product
One ingredient.
Nothing hidden.
5g of Creapure® creatine monohydrate per serving. Sourced from a single German facility. Third-party tested for every batch. No fillers, no colours, no flavour — because nothing else belongs.
- Actives
- Creapure® 5,000 mg
- Servings
- 60 per tub
- Origin
- Trostberg, DE
- Tested
- NSF · Informed-Sport
Why it works
Three quiet effects, well studied.
- Ⅰ
Strength
Sustains the phosphocreatine system that fuels the first ten seconds of every effort — from a heavy lift to standing from a chair.
- Ⅱ
Longevity
Preserves lean mass through the decades of gradual loss. Muscle is the organ of healthy aging.
- Ⅲ
Clarity
Supports cognitive energy under fatigue. The brain, too, runs on ATP.
The Ritual
One measure.
Each morning.
Stir into water. Drink. Continue with your day. The habit is small; the compounding is not.
清界Delivered every 60 days
Verified, quietly.
Creapure® Verified
NSF Certified
Informed-Sport
Third-Party Tested
Philosophy
清界
SEIKAI is not an Asian brand. It is a purity brand — obsessed with making the cleanest, most honest products for mind, body, and long-term health. We started with creatine because it is the single most studied compound for preserving strength and clarity. Then we removed everything else.
— Founder, SEIKAI
The Offer
Begin the ritual.
Two ways to keep it simple. Change, pause, or cancel at any time.
清界
Subscribe
One-time
Single tub
Try it first. No commitment, no account required.
- 60 servings · 5g Creapure®
- Flat-rate shipping
- 30-day return, no questions
$48
per tub
Questions
The science, simply.
Creatine is a naturally occurring compound found in muscle and brain tissue. It helps regenerate ATP, the cell's energy currency, supporting short bursts of effort and the maintenance of lean tissue over time.
Yes. Decades of research support daily use at 3–5 grams for healthy adults. It is one of the most studied sports-nutrition ingredients, with a strong safety profile and no requirement for cycling.
No. Creatine supports muscle quality and cellular energy, not bulk. For adults focused on healthy aging, it helps preserve the strength that carries you through daily life.
Creapure® is creatine monohydrate produced in Trostberg, Germany, to a purity standard of 99.99%. It is widely regarded as the reference standard for creatine quality.
Every batch is independently analyzed for purity, potency, and contaminants by accredited laboratories. You get exactly what the label states — nothing more, nothing less.
One 5-gram scoop each day, stirred into water. Timing is flexible; consistency matters more than the clock. No loading phase required.