Ever wondered where your tretinoin cream actually came from? The story of tretinoin and Holmesburg prison is one most skincare fans have never heard.
In this guide, we explain what happened at Holmesburg, how it links to one of dermatology’s best-known medicines, why it changed the rules on medical research, and what it means for you if tretinoin is part of your routine today.
Five key takeaways
- Tretinoin, first sold as Retin-A, was developed by dermatologist Albert Kligman, whose early skin research took place on men held in Holmesburg prison in Philadelphia.
- The Holmesburg prison experiments ran for over two decades and exposed thousands of incarcerated people, most of them Black, to drugs, chemicals and infections, often without meaningful consent.
- The University of Pennsylvania apologised in 2021, the City of Philadelphia in 2022, and the College of Physicians of Philadelphia in 2023, but survivors and families are still asking for repair.
- Cases like Holmesburg helped shape modern research ethics, including tighter rules on prisoner research and independent ethics review.
- Tretinoin itself is a well-studied, prescription-only medicine in the UK. Used correctly and under supervision, it is an effective treatment for acne and some sun-damaged skin.
What is tretinoin, and why does its history matter?
Tretinoin is a retinoid, which is a fancy way of saying it’s a close cousin of vitamin A. You’ll often hear it called retinoic acid or vitamin A acid. On skin, it acts a bit like a strict but fair foreman on a building site. It tells skin cells to turn over at a steady pace, stops dead cells piling up inside pores, and helps keep the whole operation running smoothly.
That’s why it works so well for blackheads and whiteheads, and why it became famous for softening fine lines on sun-damaged skin. If you’ve read our guide on adapalene vs tretinoin, you’ll know tretinoin is one of the most researched retinoids around.
So why dig into its past? Because the story of tretinoin and Holmesburg prison isn’t a footnote. It’s a real event that hurt real people, and it still affects how many communities feel about medicine today. Knowing it helps you make informed choices, and it reminds all of us in healthcare why consent and fairness are non-negotiable.
Holmesburg prison: what actually happened?
Holmesburg prison was a large county jail in north-east Philadelphia. From 1951, and for around 23 years, it hosted a medical testing programme run by University of Pennsylvania dermatologist Albert Kligman. Companies including Johnson & Johnson and Dow Chemical, as well as US government agencies, paid for studies there.
The scale was huge. According to reporting by the Associated Press, thousands of people held at Holmesburg were exposed to painful skin tests, surgery without anaesthetic, radiation and mind-altering drugs. Products tested ranged from hair dye and detergent to chemical warfare agents and dioxin.
Who was Albert Kligman?
Kligman was one of the most influential dermatologists of the 20th century. He wrote hundreds of papers, trained generations of skin specialists, and is still credited with inventing topical tretinoin for acne and photodamaged skin.
He also defended his prison work until he died in 2010, arguing it fitted the scientific and ethical standards of its time. Historians, survivors and, eventually, the institutions involved came to a very different conclusion.
“Acres of skin”: life inside the testing programme
In a 1966 newspaper interview, Kligman described his first visit to the prison with obvious excitement, saying he saw “acres of skin” in front of him. Those words later became the title of Allen Hornblum’s 1998 book, which first brought the Holmesburg prison experiments to wide public attention.
Hornblum ran an adult literacy programme in Philadelphia’s prisons in the 1970s and saw the effects for himself. Men walked around with patches of skin taped over, blistered or scarred. Many were awaiting trial, not convicted, and were trying to raise bail money. Payment was small, often around a dollar a day, but inside a jail that could buy essentials from the prison shop.
The City of Philadelphia later stated that most participants were Black men, many awaiting trial, and many of whom couldn’t read. Think about that for a moment. If you can’t read a consent form and you need money to get home to your family, how free is your “yes”?
How tretinoin fits into the Holmesburg story
Kligman, working with James Fulton and Gerd Plewig, published the landmark paper on topical vitamin A acid for acne in 1969. The product was patented as Retin-A and later re-patented in the 1980s after its effect on wrinkles was recognised.
The Philadelphia Inquirer’s obituary of Kligman noted that it was at Holmesburg, using prisoners as test subjects, that he worked out the original use of Retin-A. Survivors put it even more plainly, saying the drug was discovered and made at the prison. So while the published acne trials involved patients, the groundwork for the history of tretinoin is tied up with Holmesburg prison in a way that can’t be untangled.
Retin-A also brought money. The University of Pennsylvania took legal action over the patent and, in 1992, won a share of the profits. That detail matters, because it shows who benefited, and who didn’t.
Consent, coercion and why “voluntary” wasn’t really voluntary
On paper, the men at Holmesburg signed up. In practice, the choice was shaped by poverty, confinement and limited information. Here’s a simple way to picture it. Imagine being stuck in a lift for weeks. Someone offers you a sandwich if you’ll let them test an unknown cream on your back. Technically you could say no. But are you really choosing freely?
That’s the heart of the ethics problem. Consent only counts when it’s informed, voluntary and given by someone who understands the risks. Researchers also need to be independent from the people who control your daily life. At Holmesburg, many of those safeguards were weak or missing. Some participants later reported lifelong scars and health problems, and nearly 300 former prisoners sued Kligman, the university and Dow Chemical.
The long road to apology
Recognition came slowly. Testing at Holmesburg stopped in 1974, but survivors spent decades pushing for acknowledgement. In 2003, a group called the Holmesburg Survivors protested when Kligman received a lifetime achievement award.
Things began to shift in the 2020s:
- 2021: Penn Medicine apologised, recognised serious ethical concerns with Kligman’s work, renamed a professorship, ended a lecture in his name and redirected funds to dermatology research on diversity and equity.
- 2022: The City of Philadelphia formally apologised, saying that whatever the ethical norms of the time, it was wrong to exploit a vulnerable population.
- 2023: The College of Physicians of Philadelphia apologised and withdrew the award it had given Kligman.
In 2024, 50 years after the programme ended, survivors and their families were still calling for reparations. An apology is a start, but many feel it isn’t the finish line.
How research ethics changed after Holmesburg
Holmesburg wasn’t the only scandal of its era. Alongside others, it helped push governments to tighten the rules. The result is the system of checks that protects anyone who joins a clinical trial today.
From Nuremberg to the Belmont Report
The Nuremberg Code of 1947 and the Declaration of Helsinki, first adopted in 1964 and updated many times since, set out the principle that research participants must give informed, voluntary consent. In the US, the 1979 Belmont Report boiled research ethics down to three core ideas: respect for persons, beneficence and justice. Justice is the one Holmesburg failed most clearly, because the burdens of research fell on people with the least power to refuse.
What protects you in a UK study today?
In the UK, any NHS research involving people has to be reviewed by an independent research ethics committee before it starts. These committees check that consent forms are clear, that risks are reasonable, and that vulnerable groups aren’t being singled out unfairly. Studies in prisons need extra approval on top. Payments must not be so large that they pressure people into taking part, and you can always leave a study without giving a reason.
In short, the modern system was built so that a place like Holmesburg prison couldn’t happen again.
Is tretinoin safe to use today?
This is the big question many readers ask once they learn about tretinoin and Holmesburg prison. The short answer: yes, when it’s prescribed and used properly. Tretinoin’s safety and effectiveness have since been tested in many ethically approved studies with willing, informed volunteers.
What the evidence says
After the early acne work, a well-known double-blind, controlled trial in 1988 showed tretinoin improved sun-damaged skin compared with an inactive cream. In acne, NICE recommends topical retinoids, often combined with benzoyl peroxide or an antibiotic, as first-line options for many people. The NHS also lists topical retinoids among standard prescription treatments for acne.
In the UK, tretinoin is a prescription-only medicine. Licensed products include Treclin gel, which combines tretinoin 0.025% with the antibiotic clindamycin. Tretinoin on its own may be prescribed by a clinician where appropriate.
How tretinoin works, in plain English
Picture your pores as tiny drainpipes. In acne, dead skin cells and oil clump together and block the pipe, a bit like hair in a shower plughole. Tretinoin binds to retinoic acid receptors inside skin cells and switches on genes that control how cells grow and shed. Our blog on receptor binding explains this in more detail. The result is fewer blockages, fewer blackheads and, over time, fewer spots.
For sun-damaged skin, tretinoin can encourage new collagen and smoother texture. It isn’t a magic eraser, though. Think of it as a slow, steady renovation rather than an overnight makeover.
Who shouldn’t use tretinoin?
- Don’t use topical tretinoin if you’re pregnant, planning a pregnancy or breastfeeding.
- Avoid it if you’re allergic to any of its ingredients.
- It makes skin more sensitive to sunlight, so sunbeds and sunlamps are off the menu.
- Keep it away from your eyes, lips, nostrils and broken skin.
- Don’t layer it at the same time as other topical products unless your prescriber says so.
Should you feel uneasy about using tretinoin?
It’s completely understandable if this history leaves a sour taste. Many medicines and techniques we rely on today have uncomfortable origins. Honouring the people harmed at Holmesburg doesn’t mean throwing away a useful treatment. It means remembering them, telling the story accurately, and supporting the ethical safeguards that now protect everyone.
As a pharmacy team, we believe patients deserve the full picture, not just the glossy version. Trust in medicine is earned through honesty, and that includes being open about its mistakes.
Practical tips if you use tretinoin
If you and your prescriber decide tretinoin is right for you, these tips can make the journey smoother:
- Go low and slow. Start two or three nights a week and build up over two to three weeks as your skin adjusts.
- Use a pea-sized amount for your whole face. More isn’t better, it’s just more irritating.
- Apply at night on clean, completely dry skin. Damp skin can absorb more and sting more.
- Moisturise generously. A simple, fragrance-free moisturiser is your best friend.
- Wear SPF 30 or higher every day, even when it’s grey outside. Yes, even in a British summer.
- Expect a rocky start. Some redness, peeling or a mini flare in the first few weeks is common.
- Be patient. NICE suggests reviewing acne treatment at around 12 weeks.
Who, how and why: a quick recap
Who: Albert Kligman, a University of Pennsylvania dermatologist, ran the Holmesburg prison experiments on incarcerated men, mostly Black and many awaiting trial.
How: Through a long-running, company-funded testing programme that paid small sums and offered little real informed consent.
Why it matters: The work helped give us tretinoin, but at a serious human cost. It also helped reshape research ethics so that participants today are better protected.
Frequently asked questions about tretinoin and Holmesburg prison
What is the link between tretinoin and Holmesburg prison?
Tretinoin, sold as Retin-A, was developed by Albert Kligman. Much of his early skin research, including groundwork for Retin-A, took place on men held at Holmesburg prison in Philadelphia between 1951 and 1974.
What were the Holmesburg prison experiments?
They were medical and chemical tests carried out on incarcerated people for over 20 years. Participants were exposed to drugs, chemicals, infections and cosmetic products, often with very limited understanding of the risks.
Who was Albert Kligman?
He was a University of Pennsylvania dermatologist best known for developing topical tretinoin for acne and sun-damaged skin. He’s now also remembered for the ethical failings of his prison research.
Did the prisoners give consent?
Many signed forms, but most experts agree the consent wasn’t truly free or informed. Participants were often poor, awaiting trial, unable to read, and offered money that mattered inside prison.
Has anyone apologised for Holmesburg?
Yes. Penn Medicine apologised in 2021, the City of Philadelphia in 2022, and the College of Physicians of Philadelphia in 2023. Survivors and families continue to call for reparations.
Is tretinoin safe to use?
For most people, yes, when prescribed and used as directed. It has been studied in many ethically approved trials since. It isn’t suitable in pregnancy or breastfeeding and can irritate skin at first.
Can I buy tretinoin over the counter in the UK?
No. Tretinoin is a prescription-only medicine in the UK, so you’ll need an assessment from a prescriber before you can get it.
How long does tretinoin take to work for acne?
Most people notice changes after 6 to 12 weeks. Early irritation and a short flare are common, so patience and good skincare help.
Should I stop using tretinoin because of its history?
That’s a personal choice. Many people decide to keep using it while acknowledging and remembering the people harmed. If you’d prefer an alternative, a prescriber can talk you through other options.
How did Holmesburg change medical research?
It added to pressure for stronger protections, including independent ethics review, stricter rules for prisoner research, and a focus on fair, informed and voluntary consent.
Disclaimer
Disclaimer: This information is for education only and isn’t a substitute for personal medical advice. Always follow your prescriber’s instructions.
References
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- City of Philadelphia (2022) City issues formal apology for experiments conducted at Holmesburg Prison decades ago. 6 October. Available at: https://www.phila.gov/2022-10-06-city-issues-formal-apology-for-experiments-conducted-at-holmesburg-prison-decades-ago/ (Accessed: 20 October 2026).
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