The vitamin A trials that led to Dr. Kligman’s discovery that tretinoin has a positive effect on acne and facial wrinkles were only one of an extensive series of experiments. Scientists have known about vitamin A’s potential for treating acne since at least the 1940s, according to Hornblum, but studies on use stalled due to the high rate of skin irritation it caused. When a colleague wanted to see vitamin A’s impact on himself, Dr. Kligman noted the resultant irritation — and decided to conduct his experiments on prisoners anyway.
The doctor started by using extremely high doses. Currently, the most common dosage of Retin-A has a 0.025% concentration of retinoic acid and, according to the Mayo Clinic, it’s known for causing side effects like burning, stinging, peeling, redness, and irritation. Compare that with Dr. Kligman’s early studies, which used a 1% concentration on incarcerated subjects. “I damn near killed people [before] I could see a real benefit,” he told Philadelphia Magazine. “Every one of them got sick.” This lack of regard for his subjects’ pain and well-being was a constant fixture of Dr. Kligman’s time at Holmesburg, and he seemed to take pride in his drive to push the boundaries of medical ethics. “It was years before the authorities knew that I was conducting various studies on prisoner volunteers,” he once said. “Things were simpler then. Informed consent was unheard of. No one asked me what I was doing. It was a wonderful time.”
Skin care was only one of Dr. Kligman’s areas of interest. As the Philadelphia Inquirer reported, his clients also included major pharmaceutical manufacturers like Pfizer and Johnson & Johnson, chemical companies, as well as the US Army. Test subjects were exposed to asbestos and radioactive isotopes as well as to diseases like herpes and staphylococcus, the latter recalling the infamous and contemporaneous Tuskegee Syphilis Study. Per the Inquirer, the Army used the Holmesburg prisoners to test chemical agents and psychotropic drugs while the CIA experimented on them with mind-control compounds. Dow Chemical funded a study in which prisoners were exposed to dioxin, an extremely poisonous, carcinogenic component of Agent Orange — but pulled the plug after Dr. Kligman radically increased the dosage they’d prescribed. “Looking back, would similar tests be done using the prison population?” a Dow spokesperson commented in 2000. “Absolutely not.”
Dr. Kligman’s testing program was shut down in 1974, but by then the doctor was set. His discovery of Retin-A gave him enormous financial and professional success and provided cover when critics spoke up. Whenever a survivor tried to hold him accountable by filing legal charges, like Jerome Roach did in 1976 and Leodus Jones did in 1987, the case was dismissed based on insufficient evidence. In Jones’s case, Dr. Kligman elected to settle for $40,000.
The story of Holmesburg reached a wider audience in 1998 with the publication of Hornblum’s book. “What I found out and documented in Acres of Skin is that even though there were other states that allowed this to happen, and many prisons that did experiments, there was nothing like what occurred in the Philadelphia prison system,” Hornblum told Prism in a 2023 interview. When Hornblum reached out to Dr. Kligman for comment on the book, the dermatologist quickly cut off the interview after saying, “All we did… is offer them money for a little piece of their skin.”
