Latest Biological Age Results: GrimAge Epigenetic Clock + Iollo Metabolomic Clock

Quick Summary of Biological Age-relevant Results

Summary of results. Latest outputs in yellow. Average of all data indicates 39% slower aging. Note that telomere age is heavy contributor to -39% figure; without it, result is -36%.


Slow My Age is an account of my journey to achieve the lowest biological age possible, while on a realistic budget and not significantly infringing on my quality of life. In my introductory post, I explain how I arrived here. In my first epigenetic results post, I discuss the clocks in depth. For this post, I focus on my latest biological age results from two tests: GrimAge (epigenetic) and Iollo (metabolomic).

Confused about the epigenome, metabolome, biological age, and what it all means? You can learn more about the multiome and its components in this webinar I hosted, in which I spoke about the genome, epigenome, transcriptome, proteome, metabolome, microbiome, phenotype, and telomeres, and how they relate to biological age.

Note that not all biological clocks are created equal and vary in terms of accuracy and precision. However, although certain tests are more accurate than others (for example, PC DunedinPACE clock, a third generation clock, is arguably the most accurate right now), and we should put more faith in them than others, as a longevity enthusiast in the biotech industry, I find it valuable to compare results across a wide range of algorithms. It’s also elucidating to see results from clocks that compute biological age based on different biomarkers, such as the epigenome, metabolome, telomeres, and phenotypic or physiological markers.

What you will notice about my results is that all metrics indicate a younger biological age, regardless of the method. On the conservative end, the GrimAge clock calculates 17% slower aging (this clock is known to output very conservative figures) and on the aggressive end, 80% slower aging (Levine PhenoAge clock).

The average of all of my markers is 39% slower aging, and the DunedinPACE clock, which is perhaps the most accurate of all, computes 31% slower pace of aging. This aligns with my real world physiological markers of 32% slower aging. I suspect that the truth exists somewhere in that neighborhood of approximately 1/3 slower aging.

GrimAge Clock Results

I discussed the GrimAge clock in my original biological age post in 2022. I mention how the GrimAge clock often times computes biological age to be above chronological age, but what is important to look at is the strata you find yourself in. At the time, despite my GrimAge result being 3.8 years above my chronological age, I was in the top 5% strata, meaning I was aging slower than 95%+ of people tested.

Nonetheless, I still questioned my result. So, after some time I ran another blood-based analysis, this time at a different lab: The Clock Foundation, a non-profit cofounded by the father of biological age clocks, Dr. Steven Horvath.

This time, my results were more in line with all of my other age test results: minus 6.43 years, or 10.23 years lower than the initial test result.

The GrimAge clock is a second generation clock, but is considered one of the most accurate biological age clocks available, just behind DunedinPACE, which technically measures pace of aging.

As part of my score computation, I can see where I performed well and not so well. Specifically, my leptin levels were a bit high.

The ClockFoundation goes on to describe my singular risk factor as follows:

Compared to the positive contributors, leptin’s z-score negative value is not significant. Nonetheless, it is less than ideal.

Recommendations for decreasing leptin include:

  • Reduce visceral fat. As shared in a previous post, mine are extremely low, in the top quartile for a 20 year old.
  • Fast. I time restrict my eating window to 8 hours daily (16:8), and go on 24+ hours fasts once every month or so.
  • Exercise. I already do plenty of that!
  • Reduce insulin levels. My insulin levels are low, as demonstrated by my C-peptide results that have ranged between .7 to 1.4 from 2018 to present.
  • Avoid corticosteroids. Already avoiding 😉
  • Thyroid hormones. I have normal, healthy levels, and don’t take any exogenous hormones (unless you count melatonin!).

Considering I’m doing practically all I can according to these guidelines, and my levels are not too bad, I will hold off on focusing on leptin and see how it changes over time. With a healthy GrimAge result, I’m happy with where I find myself on this measurement right now.

My Metabolomic Clock Results: Iollo

My most recent biological age assessment was done via a metabolomic clock out of Stanford University and Y Combinator called Iollo.

I was excited to see the results because this clock measures 623 blood-based biomarkers, and identifies which markers are ideal, worth monitoring, and worth paying attention to.

These biomarkers are measured using mass spectrometry. In the process they actually measure more than 25,000 molecules, but they only process the 623 that research has so far found to be clinically relevant. They then take these biomarkers and compute a biological age, which “indicates whether your biomarker levels are more similar to those of a younger or an older person.”

In my case, having taken the blood sample when I was 39.2 years old, and receiving a biological age result of 27.9, it indicates a biological age that is 29% lower than my chronological age. As mentioned earlier, this result sits right in the neighborhood of my other biological age clock and physiological markers, which all indicate approximately 1/3 slower aging.

The value of metabolomic tests is that they are arguably more actionable than epigenetic tests, since your metabolome changes in as little as six weeks. For example, discontinuing refined sugar intake and engaging in HIIT training can show results on your biological age output in just over a month’s time.

I had the opportunity to speak with Iollo’s founder and CEO about my results and to dig into some of the particulars.

Iollo makes a point to adjust its outputs per metabolite based on confounders. For example, certain metabolites have seasonality effects, and others, like DHEA, have sex specific effects. Meanwhile, other metabolites are agnostic to sex and age and don’t require any adjustment.

It’s worth noting that the Iollo biological age clock is not currently a mortality-based clock, but there is hope for that to come from the team some time in the future.

Beyond biological age, Iollo also analyzes metabolites that relate to multiple categories of health and grades them as optimal, needing to be monitored, or needing attention. These grades are based on more than 40 biomarkers.

For this analysis, I had two of the 40+ biomarkers at less than optimal levels: HXX ratio (oxidative stress marker) and Asp (1 of 11 metabolic health markers).

For the oxidative stress HXX marker, Iollo explains, based on a survey I completed when I provided my blood sample, the cold I had contracted was the likely explanation for the suboptimal result. This customized explanation is quite helpful.

Iollo also explains that for my “monitor only” asparagine levels, that “they’re slightly lower than optimal but not in a range that typically causes concern.”

All other metabolites were “optimal.” Certain metabolites that caught my eye include methionine (nice to see it was low considering that I have moderately high protein intake), and spermidine (in the upper range, despite not supplementing, because spermidine is most likely not absorbable orally; more on this another time).

What’s Next?

When it comes to biological age testing, the industry is nascent. While there are certain clocks that are demonstrably more accurate and precise than others – which we make a point to license for NOVOS Age – there is continual innovation in the field.

On a personal level, I feel reassured seeing my positive biological age results being replicated across tests, biomarkers, blood samples, and over time, and am ever more confident that my affordable, achievable approach to aging is effective at climbing to the top percentile of health despite working against significant life events (brain tumor, past depression, stressors from entrepreneurship).