A new anti-aging drug appears to reverse the skin's aging clock.

After four weeks of using the cream, participants reduced their skin's biological age by an average of about two years.

A wave of biotech companies are seeking to prove that the aging process can be slowed down. Mountain View, Calif.-based Rubedo Life Sciences starts with the most obvious sign: the skin.

The company's experimental treatment shows early promise that it may slow the appearance of aging, according to data the company presented at the Aging Research and Drug Discovery Meeting in Boston earlier this month.

In a small clinical trial, Rubdo tested his topical cream on 11 people with atopic dermatitis, an inflammatory skin disease and the most common type of eczema. The drug targets the mechanism of cellular senescence, a biological state in which damaged or stressed cells do not divide permanently but do not die. These senescent or "zombie" cells accumulate with age and can release substances that contribute to inflammation and tissue damage, which contribute to disease.

After four weeks of using the cream, participants reduced the biological age of their skin by an average of two years. This estimate was based on an aging "clock" designed by another company, Mitra Bio, which performed an independent analysis on participants' skin samples. One person in this trial reduced the age of the skin by more than 11 years. Separately, Rubedo found that treatment was associated with a reduction in markers associated with inflammation and a 10 percent increase in a type of collagen associated with skin elasticity and structure.

Biological epigenetic age is an estimate of how old a person is compared to their chronological age. Aging clocks like Mithras attempt to calculate this number by looking at patterns of methylations, chemical changes in DNA that regulate how genes work and can change over time. Although this measure does not necessarily prove that the body or a particular organ or tissue has become functionally younger.

"Our idea is to find ways to reverse the course of our aging," says Marco Quarta, Robdo's founder and chief scientific officer. "Aging is complex. There are many mechanisms, but cellular senescence is one of them."

Senescent cells are also involved in normal biological processes such as wound healing and tumor suppression, but their accumulation over time is associated with many age-related conditions. Getting rid of them is one of the leading strategies pursued by antiaging and longevity companies.

Rubedo's approach aims to clear senescent cells by targeting a protein called GPX4, a gatekeeper for cell survival. By temporarily turning off GPX4, the drug is designed to make senescent cells more sensitive to ferroptosis, a regulated form of cell death, while regenerating stressed, non-senescent cells nearby.

In a separate study, researchers looked at the drug's effect on actinic keratosis, a skin condition caused by sun damage that causes rough, scaly patches of skin that can sometimes turn into skin cancer. In a test on 18 people, the cream led to a 46% reduction in total lesions after one month of use.

Rubedo is studying the same drug for psoriasis and sun-damaged skin. Soon, the company will add androgenetic alopecia, a form of hereditary hair loss, to the list. CEO Frederick Bedingfield, who was previously chief medical officer of Allergan, where he launched Botox, sees the potential for a lower-strength, over-the-counter version for general skin aging that competes with retinol. The company is also formulating the drug into a pill to investigate whether it could be used to treat metabolic conditions associated with aging.

"It's great that they're doing this," says Eric Verdin, president and CEO of the Buck Institute for Research on Aging, which has developed several aging clocks. I'd probably be a little cautious about measuring these watches because there are so many of them out there right now.

Plus, the results patients care about are how their skin actually looks and feels, not the result of a biological aging test.

Anthony Rossi, a dermatologist at Memorial Sloan Kettering Cancer Center, says aging is only one part of the aging puzzle. Some old cells are good because they shut down things like cancer progression.

The science is new, he says, but the work is still in its early stages, and it will be interesting to see how it affects biological aging in people with healthy skin, not just those with certain skin conditions. "The best anti-aging routine right now is sleep, a good diet and exercise." he says