I Checked My Biological Age at 43. The Number Was 51.

At 43, I thought I had a reasonable handle on my health. Not elite — I’m not training for anything — but functional. Sleep okay. Work out twice a week. Don’t eat garbage more than a few times a month.

Then I took a biological age quiz and got a number I didn’t expect: 51.

Eight years older than my birth certificate. That’s not a rounding error.

What Biological Age Actually Measures

Biological age is not chronological age. Chronological age counts years since birth. Biological age estimates how old your body functions — based on the same markers researchers use to study aging: sleep quality, recovery speed, energy consistency, mental clarity, body composition, hormonal output, and stress load.

Two men born the same year can have biological ages 10 to 15 years apart, depending on those factors. The gap is not fixed. It moves based on what’s happening in your body.

The most validated biological age measures come from epigenetic clocks — specifically, patterns in DNA methylation that correlate strongly with how fast different biological systems are aging. The Horvath clock and PhenoAge model are the gold standards in research. Lab-based epigenetic testing costs $300–$500 and requires a blood draw.

Lifestyle-based quizzes don’t replicate those tests. What they do is flag patterns that correlate with accelerated or decelerated aging — the same patterns researchers see in epigenetic data. They’re a reasonable first screen, not a diagnosis.

The Quiz Result

The 7-question quiz I took — the Biological Age Quiz on Verto — scored me across: daily energy, sleep quality, recovery from exercise, mental clarity, body composition, libido, and stress load.

My score by category:

• Energy: Afternoon crash most days — 2 points above baseline (worse)
• Sleep: Wake up once or twice most nights — 2 points above baseline
• Recovery: Soreness lasting 2–3 days after moderate exercise — 2 points above
• Mental clarity: Slower to find words than I was 5 years ago — 1 point above
• Body composition: BMI 27, noticeable visceral fat increase since 40 — 1 point
• Libido: Notably lower than 35–38 — 2 points above baseline
• Stress: Moderately high, consistent — 1 point

Total: 11 points above baseline. Estimated biological age: 43 + 8 = 51.

The quiz recommended investigating growth hormone decline and NAD+ depletion as likely contributors.

Why Those Two Things Specifically

Growth hormone (GH) declines approximately 14% per decade after age 30. By 43, most men have GH levels roughly 18–20% lower than at 25. Growth hormone isn’t just about muscle — it drives cellular repair, sleep quality, fat metabolism, and energy consistency. A significant decline in GH correlates with exactly the pattern I described: afternoon energy crashes, slower recovery, increased body fat.

NAD+ — nicotinamide adenine dinucleotide — is a coenzyme your cells use for energy production and DNA repair. NAD+ levels drop approximately 50% between ages 20 and 50. Low NAD+ is directly linked to reduced mitochondrial function, which shows up as sustained fatigue, brain fog, and poor recovery. It’s not the same as low GH — it’s a different mechanism producing overlapping symptoms.

Neither of these is a certainty without lab testing. The quiz flags probability, not diagnosis. But the pattern matched.

What I Did

I started with a Strut Health consultation — a telehealth platform that prescribes Sermorelin for men who are candidates. Sermorelin is a growth hormone-releasing hormone (GHRH) analogue. It doesn’t replace GH directly — it stimulates your pituitary gland to increase its own GH production. The distinction matters: synthetic HGH replacement costs $800–$1,200/month and bypasses your body’s feedback loop entirely. Sermorelin costs roughly $79–$99/month and works with the existing system.

The consultation took 20 minutes. They reviewed my symptom profile, asked about contraindications (active cancer, history of pituitary issues), and explained what realistic outcomes look like.

What Strut is clear about: Sermorelin doesn’t produce dramatic, rapid changes. What it can do — over 3 to 6 months of consistent use — is improve sleep quality (GH is secreted primarily during deep sleep, so stimulating production tends to improve sleep architecture first), support gradual changes in body composition, and reduce recovery time. Individual results vary. The platform doesn’t promise specific outcomes.

I started 90 days ago. What I noticed, in order:

1. Sleep quality improved at ~3 weeks. I’m still waking occasionally, but less often, and falling back asleep faster. This matched what the medical team said to expect first.
2. Recovery time shortened at ~6 weeks. Soreness from a hard workout now peaks at 24 hours instead of 48–72. Not dramatic, but consistent.
3. Energy is more stable at ~8 weeks. The 2 PM crash is less pronounced. Not gone, but lower amplitude.

I haven’t re-taken the biological age quiz yet. I will at 6 months.

The Honest Version of What This Is

Sermorelin is not a fountain of youth. Nothing in the longevity space is. What it is: a prescription intervention that may address one specific mechanism — declining GH production — that contributes to how men over 40 feel and function.

It’s also not the right tool for everyone. If your primary issues are low testosterone rather than low GH, TRT is a different protocol. If your primary issue is fatigue from poor sleep habits or high stress, neither addresses root cause. The Sermorelin vs HGH vs TRT wizard routes you to the right category based on your specific symptom pattern — it’s worth running before making any decisions.

The biological age quiz gave me a useful frame. The number 51 wasn’t devastating — it was actionable. It pointed at specific mechanisms. Those mechanisms had interventions. Some of those interventions have a reasonable evidence base and a reasonable cost.

That’s what a good screening tool does.

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Free tools: Biological Age Quiz — 7 questions, 60 seconds · Sermorelin vs HGH vs TRT — find your path · Hormone Decline Timeline — see your curve by age

Related: Sermorelin: Why Doctors Don’t Bring It Up First · NAD+ Therapy: 60-Day Personal Test

Start a Strut Sermorelin assessment →

Health content on Verto is informational only and does not constitute medical advice. Consult your physician before starting any hormone or peptide therapy. Individual results vary. This article contains affiliate links.