According to Gram Research analysis, a new animal study found that folic acid supplements may speed up skin cancer development in mice exposed to cancer-causing chemicals. Mice receiving folic acid supplements developed significantly more skin tumors and lesions than mice without supplements, with 100% of supplemented mice developing lesions by the end of the 20-week study. The supplements appeared to work by increasing cell division and damaging DNA repair systems, suggesting folic acid may fuel cancer cell growth under certain conditions.
A new study found that folic acid supplements, which many people take for health, may actually speed up skin cancer development in mice exposed to cancer-causing chemicals. Researchers gave mice different doses of folic acid before and during a skin cancer experiment. Mice that received folic acid supplements developed more skin tumors and lesions than mice that didn’t get supplements. The study suggests that folic acid might help cancer cells grow faster by increasing cell division and damaging DNA repair systems. While this research was done in mice, not humans, it raises important questions about folic acid supplementation and skin cancer risk that deserve further investigation.
Key Statistics
A 2026 animal study published in the Journal of Biochemical and Molecular Toxicology found that mice receiving folic acid supplements developed greater total lesion counts and lesion burden compared to mice exposed only to skin cancer-causing chemicals.
Mice receiving folic acid supplements in the study showed increased expression of folate transporters and proliferating cell nuclear antigen, proteins that indicate faster cell division and increased folic acid uptake by cells.
By the end of the 20-week study period, 100% of all mouse groups developed skin lesions, but mice receiving folic acid supplements had significantly higher tumor burden than the control group exposed only to cancer chemicals.
The study found that folic acid supplementation was associated with enhanced DNA damage and reduced expression of MGMT, a gene responsible for repairing damaged DNA in skin cells.
The Quick Take
- What they studied: Whether taking folic acid supplements affects how quickly skin cancer develops in mice exposed to cancer-causing chemicals.
- Who participated: Laboratory mice (LACA strain) divided into six groups, some receiving folic acid supplements at different doses and some serving as controls, all exposed to skin cancer-causing chemicals over a 20-week period.
- Key finding: Mice receiving folic acid supplements developed more skin tumors and lesions compared to mice that didn’t receive supplements, suggesting folic acid may speed up skin cancer growth in this model.
- What it means for you: This animal study suggests caution with folic acid supplements if you have risk factors for skin cancer, though human studies are needed to confirm these findings. Talk to your doctor before changing your supplement routine, especially if you have a personal or family history of skin cancer.
The Research Details
Researchers used a controlled laboratory experiment with mice to study how folic acid affects skin cancer development. They created a two-stage skin cancer model by first applying a cancer-initiating chemical called DMBA to the mice’s skin, followed by repeated applications of a tumor-promoting chemical called TPA. This mimics how skin cancer develops in real life through initial damage followed by repeated irritation. The mice were divided into six groups: a control group with no treatment, a group exposed only to the cancer chemicals, and four groups that received folic acid supplements at different doses either with or without the cancer chemicals. The folic acid supplementation started four weeks before the cancer chemicals were applied and continued for twenty weeks total. Researchers then examined the mice’s skin under a microscope and measured various markers of cancer development and cell damage.
This research approach is important because it allows scientists to carefully control all variables and observe the exact effects of folic acid on cancer development in a living system. By using a well-established two-stage cancer model, researchers could see whether folic acid changes how cancer develops from start to finish. The long study period of twenty weeks allowed researchers to observe both early changes and final outcomes. This type of controlled animal study provides clearer cause-and-effect evidence than observational studies in humans, making it valuable for identifying potential risks that warrant further investigation.
This study was published in a peer-reviewed scientific journal, meaning other experts reviewed the research before publication. The researchers used a standard, well-established method for inducing skin cancer in mice, which strengthens the reliability of their findings. The study included proper control groups for comparison. However, this is animal research, so results may not directly apply to humans. The study was relatively small in scope and conducted in laboratory conditions that don’t perfectly match real-world human exposure to folic acid and cancer risk factors.
What the Results Show
Mice that received folic acid supplements developed skin tumors faster and more extensively than mice that didn’t receive supplements. In the early stages of the experiment, mice getting folic acid showed higher rates of small skin growths called papillomas compared to mice exposed only to cancer chemicals. By the end of the twenty-week study, all groups of mice had developed skin lesions, but the mice receiving folic acid supplements had significantly more total lesions and greater overall tumor burden. The researchers found that folic acid supplements increased cell division in the skin, as shown by higher levels of a protein that marks dividing cells. They also found that folic acid supplements increased the activity of folate transporters, which are proteins that help cells absorb folic acid. These findings suggest that folic acid may be feeding cancer cells and helping them grow faster.
The study found that folic acid supplementation was associated with increased DNA damage in skin cells and reduced expression of a gene called MGMT that normally helps repair damaged DNA. Mice receiving folic acid supplements also showed higher levels of an enzyme called lactate dehydrogenase in their blood, which indicates increased cell damage and death. Interestingly, there was no significant difference between the two doses of folic acid tested, suggesting that even moderate supplementation may have these effects. The study found that folic acid alone, without exposure to cancer chemicals, did not cause cancer in mice, indicating that folic acid may act as a promoter of cancer rather than an initiator.
This research adds to a growing body of evidence questioning whether high-dose folic acid supplementation is universally beneficial. Previous studies have shown mixed results regarding folic acid and cancer risk, with some suggesting increased risk at high doses. This study provides a potential mechanism explaining why folic acid might promote cancer in certain contexts: by increasing cell division and impairing DNA repair. The findings contrast with the common recommendation to take folic acid supplements for general health, suggesting that the relationship between folic acid and cancer is more complex than previously understood and may depend on individual risk factors and dosage.
This study was conducted in mice, not humans, so the results may not directly apply to people. The doses of folic acid used in mice were converted from human doses, but mice metabolize nutrients differently than humans do. The study used a specific type of mouse and a specific method of inducing skin cancer, which may not represent all types of skin cancer or all populations. The research doesn’t tell us whether the effects would occur with normal dietary folic acid intake versus supplements, or whether people with different genetic backgrounds would respond the same way. The study was relatively short-term compared to human cancer development, which typically takes years or decades. Finally, this was an animal model study, so it cannot prove that folic acid causes cancer in humans, only that it may promote cancer development under specific laboratory conditions.
The Bottom Line
Based on this animal research, people at high risk for skin cancer should discuss folic acid supplementation with their doctor before starting or continuing supplements. This is particularly important for people with a personal or family history of skin cancer, those with fair skin and sun exposure, or those with precancerous skin lesions. For people without skin cancer risk factors, the evidence from this single animal study is not strong enough to recommend stopping folic acid supplements without medical guidance. People should continue to get adequate folate from food sources like leafy greens, legumes, and fortified grains, as dietary folate is important for health. More research in humans is needed before making broad recommendations about folic acid supplementation and skin cancer risk.
People with a personal or family history of skin cancer should pay close attention to this research and discuss it with their dermatologist or oncologist. People with precancerous skin lesions, those who spend significant time in the sun, and those with fair skin should also consider this information. People taking high-dose folic acid supplements for any reason should be aware of these findings. Healthcare providers who recommend folic acid supplements, particularly to patients at risk for skin cancer, should consider this research. Conversely, people without skin cancer risk factors and those getting adequate folate from food sources may not need to make changes based on this single animal study.
This animal study doesn’t tell us how quickly folic acid might promote skin cancer in humans. In the mouse study, effects were observed over twenty weeks, but human skin cancer typically develops over years or decades. If you’re concerned about your skin cancer risk and folic acid supplementation, changes in your supplement routine should be discussed with your doctor, who can monitor your skin regularly and adjust recommendations based on your individual risk factors.
Frequently Asked Questions
Does folic acid cause skin cancer?
This animal study suggests folic acid supplements may promote skin cancer development when combined with cancer-causing chemical exposure, but it doesn’t prove folic acid causes cancer in humans. More research is needed to understand if this applies to people. Talk to your doctor about your individual risk.
Should I stop taking folic acid supplements?
Don’t stop supplements without consulting your doctor. This animal study raises concerns for people at high risk for skin cancer, but it’s not definitive proof in humans. Your doctor can assess your personal risk factors and recommend whether to continue, reduce, or stop supplementation.
Is folic acid from food different from supplements?
This study tested folic acid supplements at specific doses, not dietary folate from food. It’s unclear whether the same effects occur with normal food intake. Getting folate from leafy greens and legumes is generally considered safe and healthy.
Who is most at risk from folic acid supplements?
Based on this research, people with personal or family history of skin cancer, those with fair skin, and those with precancerous skin lesions should discuss folic acid supplementation with their doctor before starting or continuing high-dose supplements.
How long does it take for folic acid to promote skin cancer?
This animal study showed effects over 20 weeks, but human skin cancer typically develops over years or decades. The timeline in humans is unknown and would depend on many individual factors including genetics, sun exposure, and dosage.
Want to Apply This Research?
- Track your daily folic acid intake from supplements and food sources, recording the dose and type of supplement. Also track any new skin changes, including new moles, growths, or changes in existing moles, with photos and dates. Note any sun exposure and use of sun protection.
- If you’re taking folic acid supplements and have skin cancer risk factors, use the app to set a reminder to schedule a conversation with your doctor about whether to continue supplementation. Document your current supplements and dosages to discuss with your healthcare provider. Set reminders for regular skin self-checks and professional skin cancer screenings.
- Create a monthly skin check routine using the app to photograph and document any changes in existing moles or new growths. Track your supplement intake and any changes your doctor recommends. Set quarterly reminders to review your skin health with your healthcare provider, especially if you continue taking folic acid supplements. Monitor for any new skin lesions or changes that might warrant professional evaluation.
This article discusses animal research findings and should not be interpreted as medical advice. Folic acid is an essential nutrient important for many bodily functions. Do not stop taking folic acid supplements or change your supplement routine without consulting your healthcare provider. This study was conducted in mice and may not directly apply to humans. People with concerns about skin cancer risk or folic acid supplementation should speak with their dermatologist or primary care physician. Regular skin cancer screening is recommended for people at high risk, regardless of supplement use.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.