se·nesce /sɪˈnɛs/ v. — to grow old Calculator free · Tracking $29 first yr
Early access
Senesce
A biological age tracker for evidence-minded humans

Calculate your PhenoAge free. Pay for streamlined tracking and insights.

PhenoAge is a peer-reviewed estimate of biological age from nine standard blood biomarkers. Punch in your numbers below — the math runs in your browser, your data never leaves your device. If you want to track it across every test you take, that's the part we charge for.

The PhenoAge calculator
9 biomarkers · 30 seconds
Chronological ageyears
Albumin
Creatinine
Glucose (fasting)
C-Reactive Protein (CRP)
Lymphocyte %percent
MCV (mean cell volume)fL
RDW%
Alkaline PhosphataseU/L
WBC count
Your PhenoAge
phenotypic years

Biomarker contribution to your score
Bars show each biomarker's contribution to your PhenoAge being older (red, right of center) or younger (green, left of center) than your chronological age. Magnitude is relative within this result.
What tracking actually looks like

One number is a snapshot. Six numbers across two years is a story.

Here's a composite illustration — a fictional user we'll call M., 41 at first test, tracked over 24 months. The line moves down. Then it moves up. Then down again. That's the actual point: this isn't a before-and-after, it's a continuous read on what your habits and your life are doing to your biology. Tracking doesn't fix anything on its own. It just makes the trajectory visible.

M. — PhenoAge over 24 months
Composite illustration · 6 lab panels · age 41 at baseline
PhenoAge Chronological
45 43 41 39 chrono 43.2 41.8 40.5 42.7 44.1 41.9 M0 M6 M12 M16 M20 M24
M0
Baseline — first physical
M6
Started strength training, reduced alcohol
M12
Consistent sleep schedule, more vegetables
M16
High-stress project, sleep disrupted, training paused
M20
Family illness, travel, no exercise
M24
Returned to routine, recovering
Detail · M12 → M20 — what moved in the wrong direction
When M.'s PhenoAge climbed from 40.5 to 44.1, three biomarkers were doing most of the work.
CRP
0.6 2.4
↑ Higher (worse)
C-Reactive Protein reflects systemic inflammation. Elevated values are associated in the research literature with poor sleep, chronic psychological stress, and reduced physical activity — patterns consistent with M.'s reported high-stress period and training pause.
— Pearson et al. 2003; Irwin 2019
Glucose
88 102
↑ Higher (worse)
Fasting glucose at this level is in the upper-normal range, but the direction of change matters as much as the absolute number. Research associates rising fasting glucose with reduced exercise, disrupted sleep, and increased intake of refined carbohydrates.
— Knutson 2007; Borghouts & Keizer 2000
RDW
12.6 13.8
↑ Higher (worse)
Red cell distribution width rises with chronic inflammation, oxidative stress, and impaired nutritional status. It's one of the strongest mortality-associated markers in PhenoAge, and tends to lag other markers — meaning movement here reflects sustained, not acute, change.
— Patel et al. 2010; Salvagno et al. 2015
Important: M. is a composite illustration based on the kinds of patterns documented in longitudinal aging and biomarker research. The values, timing, and life events are not from a real customer. The cited research is real. The associations described are observational — biomarkers move in response to many things, and individual variation is large.
R. — PhenoAge over 24 months
Composite illustration · 6 lab panels · age 38 at baseline
PhenoAge Chronological
42 40 38 36 chrono 41.5 40.2 38.9 37.3 36.4 35.8 M0 M6 M12 M16 M20 M24
M0
Baseline — concerned by initial result
M6
Cut processed food, daily walking habit
M12
Added resistance training, prioritized sleep
M16
Habits stabilized, lost 12 lb
M20
Maintenance phase, occasional fasting
M24
Now 5.6 yrs younger than chronological
Detail · M0 → M24 — sustained improvements
Over two years, R.'s biggest gains came from three biomarkers that respond to consistent lifestyle change.
CRP
2.1 0.4
↓ Lower (better)
C-Reactive Protein dropped sharply with regular physical activity, weight loss, and improved sleep. Research consistently associates these interventions with reduced systemic inflammation — though individual response varies considerably.
— Kasapis & Thompson 2005; Mora et al. 2006
Glucose
98 84
↓ Lower (better)
Fasting glucose declined as R. reduced refined carbohydrate intake and added consistent exercise. Research associates these patterns with improved insulin sensitivity and reduced fasting glucose, particularly in those starting from elevated baseline.
— Colberg et al. 2010; Hawley & Lessard 2008
Albumin
4.2 4.6
↑ Higher (better)
Serum albumin reflects protein nutrition status, liver function, and overall health. Modest increases over time are associated with improved diet quality and reduced inflammation — both relevant to R.'s reported changes.
— Don & Kaysen 2004; Gom et al. 2007
Important: R. is a composite illustration. The trajectory shown here is favorable but not typical — sustained PhenoAge improvements of this magnitude require consistent behavioral change and often a starting position with room to improve. Tracking your own scores is the only way to know which trajectory is yours.
K. — PhenoAge over 24 months
Composite illustration · 6 lab panels · age 50 at baseline
PhenoAge Chronological
52 51 50 49 48 chrono 50.5 49.8 50.2 49.6 50.1 49.9 M0 M6 M12 M16 M20 M24
M0
Baseline — looking to improve
M6
Added Zone 2 cardio 4x/week
M12
Cut alcohol entirely, intermittent fasting
M16
Sleep tracking, magnesium, strength training
M20
Same routine, frustrated by lack of change
M24
Trajectory still flat — but holding off chrono aging
Detail · The honest version — when effort doesn't move the number
K. did everything right. Their PhenoAge barely moved. Both of these things matter.
What didn't move
CRP, RDW, MCV
Stable across 24 mo
Several biomarkers, particularly inflammation and red blood cell markers, have strong genetic and constitutional components. Even significant lifestyle changes may produce only modest movement in some individuals. This is a real and well-documented phenomenon.
— Pilling et al. 2017; Kim et al. 2019
The hidden win
+2.1 yrs gap
PhenoAge vs chrono
K.'s chronological age rose from 50 to 52 over 24 months. Their PhenoAge stayed at 49.9. The gap between PhenoAge and chronological age widened — meaning K.'s biology is now meaningfully younger relative to their age than it was at baseline. Without tracking, this would be invisible.
— Levine et al. 2018
What this means
Context matters
Why we track
A flat PhenoAge in someone who's aging chronologically is not the same as failure. It may reflect successful resistance to age-related decline that would otherwise have occurred. The number on its own can mislead; the trend over time is what tells the story.
— Belsky et al. 2020
Important: K. is a composite illustration. Many people in the longevity space experience exactly this pattern — significant lifestyle effort, modest absolute movement in their biological age score. Tracking the gap between PhenoAge and chronological age over time often reveals what a single snapshot cannot.
What we're building →

Build your own version of M.'s chart.

You already have the first data point — your PhenoAge from the calculator above. The paid tracker handles everything after that: saving each test, parsing your lab PDFs automatically, comparing what changed since your last result, and reminding you to retest before you forget. You bring the labs. We handle the math, the memory, and the comparison.

$29
first year (then $49/yr) · early access
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Built on PhenoAge. Not invented in a marketing meeting.

PhenoAge is a biological age estimator developed by Morgan Levine and colleagues in a 2018 peer-reviewed study, validated against mortality outcomes in the NHANES dataset.

It uses nine biomarkers that come standard on a complete blood count, comprehensive metabolic panel, and C-reactive protein test — the labs most adults already get at their annual physical.

The algorithm is open, the paper is public, and the calculator above implements it directly. You can verify the math yourself.

Levine, M. E., et al. (2018). "An epigenetic biomarker of aging for lifespan and healthspan." Aging, 10(4), 573–591.

doi.org/10.18632/aging.101414

Why these nine? Each one independently associates with mortality risk in large population studies. Albumin tracks liver and kidney function. CRP captures systemic inflammation. RDW correlates with chronic disease burden. Glucose with metabolic health. And so on.

Combined with chronological age and weighted by their mortality coefficients, they produce a score that estimates how old your physiology looks compared to a reference population. Lower than your chronological age is favorable. Higher means something is worth attention.

It is not a diagnosis. It is not a medical device. It is a research-grade signal that, tracked over time, can tell you whether your trajectory is moving in the direction you want.

The fine print, in plain language.

If the calculator is free, what am I paying for?

The math is free because the math is published — we didn't invent it and we won't pretend otherwise. What costs money to build and maintain is everything around the math: saved history across years, automatic parsing of your Quest and Labcorp PDFs so you never type biomarker values again, per-test reports that compare what changed since your last result, and the reminder to retest before you forget. If you only ever want to calculate your number once, use the free calculator above — that's what it's for. If you're actually trying to track this over time, the $49/year (or $29 for your first year, if you sign up during early access) buys you not having to maintain a biomarker spreadsheet for the rest of your life.

Where does my lab data come from? Do I need a new blood draw?

No new blood draw is needed if you already get an annual physical. The nine biomarkers PhenoAge uses (CBC, CMP, and CRP) are some of the most commonly ordered tests in primary care. Pull your last lab report from your doctor's portal, Quest's MyQuest, or Labcorp's portal, and type the values into the calculator above. If your doctor doesn't order CRP, you can add it for around $20 at most direct-to-consumer lab services.

Do I have to wait years for this to be useful?

No. If you've had bloodwork done in the past — and most adults have — you can backdate as much history as you can find. Sign up, dig the last few years of lab PDFs out of your patient portal, enter them with their test dates, and you have a trend line on day one. The product gets meaningfully more useful with three historical data points than with one, and most people have more old labs in their portal than they realize. This is one place we're structurally different from the kit-based services — their algorithms only work on tests they sell you, so you start at zero on day one. We use peer-reviewed math that runs on any standard lab panel, including ones you got years ago.

How is this different from the expensive blood-testing subscription services?

Most biological age products bundle the testing with the analysis — they sell you a $300+ blood draw, run their own proprietary scoring, and lock you into their kit. We don't sell labs and we don't ship anything. You bring the bloodwork you already get from your doctor or Quest or Labcorp, we run a peer-reviewed open algorithm on it, and we charge $29–49 a year for the tracking. Two real differences worth naming: we're an order of magnitude cheaper because we're doing an order of magnitude less, and because we work on standard labs rather than a proprietary kit, every previous lab panel you've ever had can be your starting trend line. With kit-based services, you start at zero the day you sign up. With us, you start with however much history you can find in your patient portal.

Is this medical advice?

No, and we won't pretend otherwise. PhenoAge is an educational tool and a research-validated estimate. We don't diagnose, treat, or prevent any disease. We don't tell you to take supplements. If your biomarkers look unusual, talk to your doctor — they ordered the test in the first place. Our terms of service say all of this in more legalese.

What do you do with my data?

The free calculator above runs entirely in your browser — your biomarker values never touch our servers. When the paid tracker launches, we'll store the nine biomarker values and the dates of your tests so you can see them across time. That's it. We won't keep the original PDFs after parsing them. We won't share or sell your data to anyone, ever — not advertisers, not data brokers, not "research partners." You can export everything as a file, or delete your account, anytime. We are not a HIPAA-covered entity (we're a consumer wellness tool, not a healthcare provider), but we treat your data with at least that level of care.

Who's building this?

A very small team. We're not VC-backed. We're not chasing a billion-dollar exit. We want to build a useful tool that pays for itself, treats users like adults, and stays around for a long time. If that resonates, you're in the right place.