In medicine, few creams have achieved cult status quite like Retin-A. Dermatologists prescribe it. Beauty influencers swear by it. Millions apply it nightly in pursuit of clearer, younger-looking skin.
Few know that some of the earliest human experiments behind its rise took place inside the walls of Holmesburg Prison in Philadelphia, where incarcerated men became test subjects in one of America’s most controversial medical research programs.¹
The rise of tretinoin transformed acne and anti-aging treatment worldwide, but its origins remain tied to one of the most controversial chapters in dermatology research
Tretinoin, commonly known under the brand name Retin-A, is widely regarded as one of the most effective topical treatments in dermatology. It is prescribed for acne, hyperpigmentation, photoaging, and fine wrinkles, and has become a major part of modern skincare culture.¹
However, behind the scientific success of tretinoin lies a deeply disturbing history involving unethical human experimentation at Holmesburg Prison in Philadelphia. The development of Retin-A remains closely associated with dermatologist Albert Kligman, whose scientific achievements transformed dermatology while simultaneously raising major ethical concerns that continue to be debated today.²
Tretinoin is a vitamin A derivative belonging to the retinoid family. It works by accelerating epidermal cell turnover, reducing follicular plugging, stimulating collagen production, and improving skin texture and pigmentation.³
Initially developed for acne treatment, tretinoin later became one of the earliest scientifically validated anti-aging therapies after researchers observed improvements in wrinkles, photodamage, and skin roughness among users.4
Today, tretinoin is frequently promoted online as a “miracle skincare ingredient,” particularly on social media platforms where anti-aging and “glass skin” trends dominate beauty culture.
Between 1951 and 1974, Holmesburg Prison in Philadelphia became a major site for dermatological experimentation under the supervision of Albert Kligman.
Many prisoners came from economically disadvantaged backgrounds, and a large number were African American inmates. Participation in medical studies offered small payments that prisoners often used for legal aid, family support, or prison necessities. Critics later argued that these financial circumstances made true informed consent impossible.
In a widely criticized 1966 interview with the Philadelphia Inquirer2, Kligman described his first impression of Holmesburg Prison by stating:
All I saw before me were acres of skin. It was like a farmer seeing a fertile field for the first time.
Albert Kligman, Dermatologist
The quote later became symbolic of the dehumanizing approach associated with the experiments conducted at Holmesburg.
According to Allen M. Hornblum’s landmark investigative book, Acres of Skin: Human Experiments at Holmesburg Prison, prisoners at Holmesburg were subjected to numerous cosmetic, pharmaceutical, and chemical experiments over several decades.
The experiments reportedly involved testing perfumes, shampoos, creams, liquid diets, and pharmaceutical products. Major pharmaceutical companies, chemical manufacturers, and even military-linked organizations allegedly funded portions of the research.
Prisoners underwent repeated “patch tests” involving experimental substances applied directly to their skin. Survivors later described severe irritation, painful burns, scarring, biopsies, injections, and prolonged dermatological reactions.
According to Hornblum’s documentation and later survivor accounts, some inmates were exposed to highly toxic substances including dioxin, a carcinogenic compound associated with Agent Orange. Other prisoners were reportedly intentionally exposed to infectious agents and experimental compounds without fully understanding the risks involved.
Hornblum also documented that women incarcerated within Philadelphia’s prison system participated in menstrual product testing and other medical studies, with several later reporting long-term physical and psychological effects.
Growing criticism surrounding prison experimentation and medical ethics eventually led to the closure of the Holmesburg research program in 1974.
Albert Kligman’s research involving vitamin A derivatives eventually contributed to the development of tretinoin.
Kligman, working alongside dermatologist James Fulton at the University of Pennsylvania, helped establish topical all-trans retinoic acid as an acne treatment during the late 1960s. Retin-A was patented for acne therapy in 1967, and the United States Food and Drug Administration approved topical tretinoin for acne vulgaris in 1971.⁵
The University of Pennsylvania licensed the formulation for commercial development, and it was later marketed by Ortho Pharmaceutical under the Retin-A brand name.⁶
Participants experienced severe peeling, redness, irritation, and burning reactions during early trials. Kligman himself later acknowledged the intensity of these side effects in interviews discussing the early stages of Retin-A development.
By the late 1980s, Kligman’s research on photoaged skin helped establish tretinoin as one of the first scientifically validated topical anti-aging therapies, expanding its influence far beyond acne treatment.⁷
Despite the controversies surrounding Holmesburg Prison, Albert Kligman remained one of the most influential dermatologists of the twentieth century. His research significantly shaped the understanding of acne, contact dermatitis, skin irritation testing, photoaging, and retinoid therapy.2
These discoveries helped establish tretinoin as one of the first evidence-based anti-aging treatments in dermatology.
Yet Kligman’s scientific legacy remains inseparable from the ethical criticism surrounding Holmesburg Prison.
For decades, survivors of the Holmesburg experiments struggled to obtain recognition and accountability. Many legal attempts reportedly failed because of insufficient documentation and lack of evidence.
Public attention surrounding the case increased in recent years amid broader conversations about racial inequality, medical exploitation, and unethical research practices.
In 2022, the city of Philadelphia formally apologized to Holmesburg survivors for the harm caused by the prison experiments. In 2023, the Society for Investigative Dermatology revoked an award named after Albert Kligman and publicly apologized to survivors and their families.2
Despite these acknowledgments, survivors and advocacy groups continue to demand compensation and broader accountability.
The story of Retin-A serves as a reminder that scientific innovation should never come at the expense of human dignity and informed consent.
Modern skincare culture often celebrates the visible benefits of tretinoin, but the history behind its development also carries the invisible scars of the men and women subjected to experimentation at Holmesburg Prison.
Every tube of tretinoin represents one of dermatology’s greatest breakthroughs. But hidden beneath its promise of clearer skin lies a history that forces medicine to ask an uncomfortable question: when scientific progress leaves scars on its subjects, who truly pays for innovation?
Skinonyms. “The Origins and History of Tretinoin.” Accessed May 11, 2026.
https://skinonyms.com/tretinoin-history
Casale, Jennifer. “Albert M. Kligman, MD (1916–2010): A Controversial Genius in Dermatology.” Clinics in Dermatology 41, no. 1 (2023): 102–104.
https://pmc.ncbi.nlm.nih.gov/articles/PMC9891217/
Balado-Simó, Paula, et al. “An Updated Review of Topical Tretinoin in Dermatology.” Journal of Clinical Medicine 14, no. 22 (2025): 7958.
https://doi.org/10.3390/jcm14227958
Stüttgen, Gerd. “Historical Perspectives of Tretinoin.” Journal of the American Academy of Dermatology 15, no. 4, Part 2 (1986): 735–740.
https://doi.org/10.1016/S0190-9622(86)70263-9
Hornblum, Allen M. Acres of Skin: Human Experiments at Holmesburg Prison: A Story of Abuse and Exploitation in the Name of Medical Science. New York: Routledge, 1998.
https://www.routledge.com/Acres-of-Skin-Human-Experiments-at-Holmesburg-Prison/Hornblum/p/book/9780415923365
Kligman, Albert M., and Zheng Zhen-Yu. “Topical Retinoic Acid for Photoaged Skin.” Journal of the American Academy of Dermatology 15, no. 4, Part 2 (1986): 836–859.
https://doi.org/10.1016/S0190-9622(86)70271-8
Fulton, James E., Jr., and Albert M. Kligman. “Topical Vitamin A Acid in the Treatment of Acne Vulgaris.” Archives of Dermatology 99, no. 4 (1969): 469–476.
https://doi.org/10.1001/archderm.1969.01610280073011
