Your age is one number.
Your future is four.
Strength. Muscle. Engine. Balance. Four numbers predict how the next thirty years go — whether you carry the groceries at 70, get off the floor at 80, and stay the one others lean on. Test yours this weekend. Then start moving them.
Strength is how you stay free.
Muscle is the currency of aging
After 30, untrained adults lose 3–8% of their muscle every decade. Muscle is what stands between a stumble and a hospital, between independence and needing help. It can be rebuilt at any age — and we measure it.
Endurance is a floor, not a finish line
We're not here to get you across a finish line. We keep enough engine to live on — and put the real work where it pays for decades: under load. The medal doesn't stop the fall at 74. The muscle does.
Proof over promises
No transformation photos. No vague "wellness." Four numbers, tested at home, re-tested every 90 days. Either they moved or they didn't — and we publish our members' aggregate results either way.
Four numbers. Twenty minutes. No gym.
Each one is a research-backed predictor of how you'll live, move, and stay independent. Each one is testable in your living room — and trainable at any age.
Strength
Grip and carrying strength are among the strongest predictors of how you age. This is the number that carries groceries, luggage, and grandkids.
Muscle
Lean mass protects bones, joints, metabolism, and recovery from every setback life throws. It declines by default — unless you interrupt it.
Engine
Your cardiovascular floor — the capacity for stairs, hills, hard days, and long trips. We build enough engine to live well, not to race.
Balance
Falls are the #1 cause of injury after 65 — and balance is trainable now. This is the difference between a bounce-up and an ambulance.
The scale.
The mirror.
The medal.
- Pounds lost this month — regained next year
- Before-and-after photos at flattering angles
- Finish lines that prove nothing at 74
- "Wellness" you can't test, track, or trust
What your body can actually do.
- How much you can carry — and for how long
- The muscle you're keeping and building
- A capacity floor that makes life easier
- Whether you get off the floor without your hands
Test. Train. Prove it.
Get your 4 Numbers
A 2-minute quiz, then a 20-minute at-home test protocol. You'll know exactly where you stand for your age and sex — no guessing, no gym.
Run the Reset
Three joint-smart strength sessions a week, a protein playbook, and daily accountability. Built for bodies with a history — knees, shoulders, backs included.
Face the Gauntlet
Re-test all four numbers with the community. Earn your rank. Watch the numbers move — because what gets measured gets built.
Read the label. Buy in this order.
Nothing on this shelf replaces the training. A short list of what's worth your money, ranked by where the first dollar goes — protein before anything, and everything else only after the basics are handled.
Protein
The one that moves the Muscle number. Most adults over 40 are well short of the target in the Playbook; this closes the gap on the days food doesn't.
Magnesium
Sleep and recovery, which is where the training actually gets banked. Cheap, boring, and the one people notice when they stop.
Collagen
For the joints doing the carrying. Belongs on the shelf after protein is handled, not instead of it.
Some links on this page are affiliate links; Second Prime may earn a commission at no extra cost to you. Nothing here is medical advice — talk to your physician before adding any supplement, especially if you take prescription medication.
The whole shelf, in order
“My first prime happened to me. This one is on purpose.”
Second Prime was built on a simple refusal: the refusal to accept that the second half of life is a managed decline. Not for me, and not for the people counting on me.
I test my own four numbers every quarter and publish them — wins and plateaus alike. This brand asks nothing of you it doesn't ask of me first.
Find out where you stand. Then change it.
Take the 2-minute quiz, run the at-home tests this weekend, and get your personal 4 Numbers scorecard — scored against your age band, with the exact place to start.
Get Your 4 Numbers