FOXO4-DRI

Senolytic peptide · Also known as FOXO4-D-Retro-Inverso, Proxofim

What is foxo4-dri?

A D-retro-inverso peptide designed to selectively eliminate senescent ("zombie") cells by disrupting the interaction between FOXO4 and p53 proteins. It forces senescent cells into apoptosis while leaving healthy cells unharmed.

FOXO4-DRI was developed by researchers at Erasmus University Medical Center in the Netherlands and published in Cell in 2017. The peptide demonstrated the ability to reverse aspects of aging in naturally aged mice, including restoring fur density and kidney function. Cleara Biotech was formed to commercialize this research, though the compound remains in preclinical development.

Key takeaway: FOXO4-DRI is the first peptide-based senolytic agent shown to selectively clear senescent cells in aged mice, but no human clinical trials have been conducted.

Benefits & evidence

Senescent cell clearance Preliminary confidence
Tissue homeostasis restoration Preliminary confidence
Age-related testosterone improvement (animal) Preliminary confidence
Kidney function improvement (animal) Preliminary confidence

How it works

Senescent cells accumulate with age and secrete inflammatory molecules that damage surrounding tissue. These cells survive because FOXO4 protein binds to p53 in the nucleus, preventing p53 from triggering apoptosis (programmed cell death). Essentially, FOXO4 acts as a bodyguard keeping senescent cells alive.

FOXO4-DRI is engineered to compete with endogenous FOXO4 for p53 binding. When it disrupts this interaction, p53 is released from the nucleus and translocates to the mitochondria, where it triggers the intrinsic apoptosis pathway. Because healthy cells have low levels of both FOXO4 and nuclear p53, the peptide is selective for senescent cells. In animal studies, FOXO4-DRI showed an 11.7-fold selectivity for senescent cells over normal cells.

Dosing information

Typical dosing protocol
Starting dose

250 mcg/day subcutaneous

Weeks 1-4
Maintenance dose

250-500 mcg/day subcutaneous

8-16 week cycles

No human clinical trials exist. These are community-reported protocols. In the original mouse study, FOXO4-DRI was administered at 5 mg/kg via intraperitoneal injection three times per week. Human dosing is extrapolated and unvalidated. Consult a healthcare provider.

Side effects

Most side effects tend to improve as your body adjusts.

Injection site reaction Common
Fatigue Uncommon
Mild flu-like symptoms (from senescent cell clearance) Uncommon
Unknown long-term effects Unknown

Research (10 studies)

FOXO4-DRI regulates endothelial cell senescence via the P53 signaling pathway. Frontiers in bioengineering and biotechnology · 2025
Cellular senescence in the aging and diseased kidney. Journal of cell communication and signaling · 2018
[Molecular regulative mechanisms of aging and interventional effects of Chinese herbal medicine]. Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica · 2017