The Epigenetic Clock: You Have Two Ages, and One of Them Doesn't Lie

The epigenetic clock estimates your biological age from chemical tags (methylation marks) at specific spots on your DNA. In healthy people it usually lands within a few years of your real age, and the gap above or below that number is linked to future health and lifespan. Key facts • In 2013, Steve Horvath at UCLA built a clock from 353 DNA sites using about 8,000 samples from 51 healthy tissues and cell types. Half the time, its estimate was within 3.6 years of a person's real age (Horvath, 2013). • Later clocks such as PhenoAge (2018) and GrimAge (2019) were trained on health and mortality data, and predict lifespan better than the first clocks (Levine et al., 2018; Lu et al., 2019). • In a small 8-week trial in men, a diet, sleep, exercise and relaxation program lowered the Horvath clock reading compared with controls. The authors call for larger trials (Fitzgerald et al., 2021). • In 2020, a Harvard team switched on three of the four Yamanaka factors (Oct4, Sox2, Klf4) in mouse eye nerve cells, restored a younger methylation pattern and reversed vision loss. This has not been done in humans (Lu et al., 2020). • A 2016 study found Holocaust survivors and their adult children both had altered methylation in one stress gene, FKBP5 (Yehuda et al., 2016). This is a single gene in a small study, not an inherited epigenetic clock. Chapters 00:00 What is your biological age? 00:37 Can you be biologically younger or older than your age? 01:37 How does the Horvath clock work? (353 sites) 02:26 PhenoAge and GrimAge: clocks that predict lifespan 02:48 What speeds up your epigenetic clock? 04:14 Can you reverse your epigenetic age? 04:53 Reversing the clock in mice (Harvard) 05:09 What's proven and what isn't 05:46 Can children inherit your epigenetic age? Sources Horvath, Genome Biology (2013): https://doi.org/10.1186/gb-2013-14-10-r115 Levine et al., Aging (2018): https://doi.org/10.18632/aging.101414 Lu et al., Aging (2019): https://doi.org/10.18632/aging.101684 Fitzgerald et al., Aging (2021): https://doi.org/10.18632/aging.202913 Lu et al., Nature (2020): https://doi.org/10.1038/s41586-020-2975-4 Yehuda et al., Biological Psychiatry (2016): https://doi.org/10.1016/j.biopsych.2015.08.005 This video is for information only, not medical advice. This episode is part of the Human Decoded library — the channel that decodes the actual biology of being human. 🧬 Subscribe for biology decoded weekly. #EpigeneticClock #DNAMethylation #BiologicalAge #Epigenetics #Aging