Nobody rocks baldness like Dwayne Johnson. Until hairless humans manage to harness the confidence it takes to show off a nude scalp like the Rock, baldness will remain high on our list of natural biological processes we want to stymie with medicine. A couple of hair-growing drugs exist, but the side effects — erectile dysfunction, anyone? — make hairlessness seem almost appealing. On Tuesday, researchers publishing in PLOS Biology added another successful drug to the list, along with its potentially serious side effects.

The paper, first-authored by Nathan J. Hawkshaw, Ph.D., of the University of Manchester’s Centre for Dermatology, presents a new compound, called WAY-316606, that enhanced hair growth in samples of human hair follicles from hair transplant patients in a small study. The team discovered its effectiveness by first testing a different drug, cyclosporin A, that’s been shown to boost hair growth in the past. The problem with cyclosporin A, an immunosuppressant drug that’s usually used on people receiving organ transplants, is that it’s also too toxic for regular use. So, the team analyzed how it promotes hair growth on a molecular level, discovering that WAY-316606 can do the same thing. But of course curing baldness can’t be that easy.

In a tweet on Wednesday, Ali Torkamani, Ph.D., the Director of Genomics at the Scripps Translational Science Institute, noted the potential side effects of both the new drug in the paper and old drugs for hair loss, suggesting that the hair growth benefits don’t outweigh the costs.

In an email to Inverse, Torkamani said he was “referring to the erectile dysfunction risk linked to the available treatment for male pattern hair loss – finasteride.” (A drug called minoxidil is the only one available for male and female hair loss.) The link is “controversial,” he’s careful to point out, but some research, like this 2012 study in PeerJ, has demonstrated the correlation.

The concern with the new drug, WAY-316606, he says, is that it affects the regulation of the body’s Wnt pathway, in which aberrant regulation is known to be linked to increased cancer risk. “We don’t know if this particular drug will increase cancer risk, but it is a very prominent concern for any drug targeting the Wnt pathway,” he says. In the paper, the researchers acknowledge the dangers of messing with Wnt, but they explain that the drug’s specific mechanism of action inside cells might allow it to avoid cancer.

Because inhibiting SFRP1 by WAY-316606 only facilitates Wnt signalling through ligands that are already present in the human HF, this ‘ligand-limited’ strategy for promoting human hair growth may circumvent potential oncological risks typically associated with β-catenin stabilisation.

In short, time will tell whether this drug is safe. For what it’s worth, WAY-316606 really did look promising in the trial, which tested the drug on 40 samples. Treatments took place over six days, and the results appeared quickly: “WAY-316606 significantly increased hair shaft production (elongation) as early as 2 days following treatment,” the team writes. Follow-up experiments on actual humans with hair loss will determine whether WAY-316606 can be used safely. In the meantime, anyone feeling down about their thinning mops should take a look at the photos of the Rock below, a clear indication that hairier is not always better.

the rock dwayne johnson
Skin is in.