An evidence-led gym & nutrition companion

Strength, kept honest.

Training and nutrition built on evidence, with a quiet rhythm of faith if you want it. Use everything free for seven days, no account and no card. After that, one payment, and it's yours.

Coming soon to iOS and Android

Invite only for now, and built in the open.

[ app screenshot ]
the daily hub
to swap
Why Aretia

Everything else rents you. This is built to be owned.

Every serious training app rents itself by the month, ties your data to an account, and asks you to trust numbers it never shows you. Aretia is the opposite, on all four counts.

Cited, not guessed

The evidence is shown

Every number traces to a published study. If I cannot back a claim, it does not ship.

Gym and kitchen

One honest tool

Training and nutrition in one place, both held to the same standard of proof.

Faith, if you want it

On by default, optional

A daily rhythm of faith sits at the heart, and switches off cleanly if it is not for you.

Pay once

No account, no rent

Seven days free with nothing to sign. Then one payment, offline, and it is yours.

The engine

Bring a split, it scores it. Bring your goals, it builds one.

One deterministic engine, no AI. It reads any training week against the same metrics, whether you brought the split or it wrote it for you.

Rate my split
01 — Type your week

Add each day's exercises, however you write them. Slang and abbreviations resolve to the real movement.

02 — It counts the work

Weekly sets and frequency for every muscle, with indirect work counted as half a set.

03 — Scored on the evidence

Each muscle against the volume and frequency the research supports, then the fixes, worst first.

The verdict
72/ 100
Strong where you enjoy it, thin where it counts.
What to fix · worst first
Not trained
Nothing in your week hits the rear delts directly.
Rear delts
Once a week
Quads and hamstrings are trained hard, but only once. Twice a week grows more at the same volume.
QuadsHamstrings
Low volume
Back sits near six direct sets a week. The evidence points closer to ten.
Back
Every muscle, by the week
SetsFreq
ChestAmple182x
BackLow62x
ShouldersProductive122x
Rear deltsUntrained00x
BicepsAmple153x
TricepsProductive92x
QuadsProductive101x
HamstringsLow41x
GlutesIndirect0
CalvesProductive82x

An illustrative read. Yours is scored from your own week.

Or build one

Tell it your days, goal, experience and equipment. It writes a split that lands every muscle in the productive range, then lets you swap any lift for one you prefer.

Push Pull Legs, twice through
Six days · intermediate · full gym
Push 1 · Strength
Barbell bench press4 × 5-81-2 RIR
Overhead press3 × 6-101-2 RIR
Incline dumbbell press3 × 8-120-2 RIR
Lateral raise3 × 12-200-2 RIR
Overhead triceps extension3 × 8-120-2 RIR
Cable pushdown3 × 10-150-2 RIR
Every slot swaps for one you prefer  ·  Cardio added on a cut  ·  Each number cited

An illustrative day. Yours is generated from your profile.

The evidence

Every dial the formula turns, and the study behind it.

Aretia is a calculator, not an opinion. If I cannot back a number with research I have read and checked against its source, it does not ship. Here is what the engine measures, and where each rule comes from.

Volume
Targets roughly ten to twenty hard sets per muscle a week, scaled to your level. Growth rises with weekly sets, with diminishing returns.
Schoenfeld, Ogborn & Krieger (2017) · PMID 27433992
Pelland et al. (2026) · PMID 41343037
Frequency
Every muscle at least twice a week. At matched weekly volume, twice beats once.
Schoenfeld, Ogborn & Krieger (2016) · PMID 27102172
Load & reps
Heavy and low on the main lift, higher reps on the isolation work. Growth is similar across loads taken near failure, while heavier favours strength.
Schoenfeld, Grgic, Ogborn & Krieger (2017) · PMID 28834797
Effort
Stop about zero to three reps short of failure. Training to failure is not required for growth.
Refalo, Helms, Trexler et al. (2023) · PMID 36334240
Lengthened work
Prefers exercises that load a muscle in the stretched position. Training through length builds more size.
Pallarés et al. (2021) · PMID 34170576
Sato et al. (2021) · PMID 34616309
Maeo et al. (2023) · PMID 35819335
Indirect work
A muscle that only assists counts as half a set, so the big lifts are never double counted into junk volume.
Pelland et al. (2026) · PMID 41343037
Cardio on a cut
Easy cycling or an incline walk rather than running, so the deficit does not cost you muscle.
Wilson et al. (2012) · PMID 22002517

Every study read and checked against its source. Read the full list, and it ships inside the app.

Nutrition

The same rule, applied to your plate.

Your calorie and macro targets come from a published formula, not a guess. Mifflin-St Jeor sets the baseline, then the research sets your protein and your rate of change.

Your food comes from the USDA database, where every value is sourced rather than typed in by strangers. It is a clean, sourced whole-foods library, with quick entry for everything else. Correct beats exhaustive and wrong.

BMR activity your goal protein the rest in carbs

Runs offline, in kilojoules or calories, like the rest of the app.

[ app screenshot ]
macro counter
to swap
On faith

Faith is built in, not bolted on.

“My faith has not always been steady, but I am working on it, and having something that reminds me to be grateful helps. I believe training and God go hand in hand. He gave us these bodies, and the ability to shape them into something we can be proud of, no matter where we are in our training. For me it goes past training. The gym has always been where I clear my head, and faith does the same kind of work. When I trust God and take care of myself, I feel like the best version of myself, and that version keeps improving. I am building Aretia to help other people find that too.”

— Blake, maker of Aretia

Faith is on by default. You can turn it off in settings, and everything else still works.

From the maker

I'm Blake, a junior application engineer. Direction and accountability have always been my hardest problems. I lose motivation easily, and the next step has rarely come easy to me. The only two things that ever pulled me forward were my faith and the gym, so I built Aretia around both. The faith side is on by default and easy to switch off. Either way you pay once, and it's yours.

If that sounds like you, leave your email below. I will only write when there is something real to share.