From Anirva. This article is general information, not medical advice. These statements have not been evaluated by the Food and Drug Administration. This article is not intended to diagnose, treat, cure, or prevent any disease.
Polypodium leucotomos (PL), a fern extract with a long history of traditional use, has drawn research interest for antioxidant and anti-inflammatory activity relevant to UV-exposed skin. Here's what that research actually shows — and why it's a supplement to sun protection, not a substitute for it.
In this article
Key Takeaways
- Polypodium leucotomos (PL) is a fern native to Central and South America with a long history of traditional use for skin conditions.
- Research has studied PL's antioxidant and anti-inflammatory activity in connection with UV-exposed skin, mostly in laboratory, animal, and small human studies.
- PL has not been shown to prevent skin cancer, and it is not a substitute for sunscreen or other proven sun-protection measures.
- PL is generally taken as an oral supplement alongside, not instead of, topical sun protection — check with a doctor before starting, especially if you're on other medications.
What Is Polypodium Leucotomos?
Polypodium leucotomos is a tropical fern native to Central and South America. Its rhizomes and leaves have a long history of traditional use as an oral remedy for various skin conditions, and commercial extracts have been sold since the 1970s. That traditional history is real, but it isn't the same thing as clinical proof — robust evidence for most of these traditional uses is still limited.
UVA and UVB, Briefly
Sunlight includes UVA and UVB radiation, both of which reach the earth's surface and penetrate skin (1). UVA is associated with deeper skin changes like photoaging; UVB is associated with sunburn and is a known risk factor for skin cancer. Proven protection against both includes sunscreen, protective clothing, shade, and limiting peak-sun exposure — see our UVA and UVB Rays article for more on this.
Active Compounds
PL extract contains a mix of antioxidant polyphenols, including several hydroxycinnamic and hydroxybenzoic acid derivatives, along with flavonoids (2). These compound classes are generally studied for antioxidant activity.
How It Has Been Studied
Antioxidant activity
Research has looked at PL's antioxidant compounds and their ability to neutralize free radicals generated by UV exposure, including reactive oxygen species (2). This research is mostly at the compound and cell level.
Inflammation and immune activity
Some research has looked at PL's anti-inflammatory properties and a possible role in moderating UV-related immune suppression in skin (3). Separate early research has looked at Langerhans cells, immune cells in the skin, and whether PL may help preserve their numbers after UV exposure (6).
UVB and skin cancer risk factors
Laboratory and animal research has studied PL's effect on UVB-induced DNA damage, including a type of damage called cyclobutane pyrimidine dimers, and on sunburn-associated skin reddening (4). This research describes a studied mechanism in cell and animal models — it is not clinical proof that PL prevents skin cancer in people.
Collagen and skin structure
Other research has looked at a possible role for PL in supporting collagen production, relevant to skin thickness and elasticity (5).
What the Research Does Not Yet Show
PL has not been shown to prevent, treat, or cure skin cancer, eczema, psoriasis, or any other skin disease, and it has not been shown to replace sunscreen or other proven UV-protection measures. Most of the research on PL and skin is laboratory, animal, or small-scale human research, not large clinical trials. If you have a photosensitivity condition or are undergoing phototherapy, talk to a dermatologist about what's right for you rather than relying on a supplement alone.
Things to Know Before Trying It
Frequently Asked Questions
Does Polypodium leucotomos prevent skin cancer?
Can I take PL instead of wearing sunscreen?
Does PL treat eczema or psoriasis?
References
- UVA and UVB radiation and skin effects: a review. PMCID: PMC3709783.
- Polypodium leucotomos polyphenol and flavonoid content: a review. PMCID: PMC4345929.
- Polypodium leucotomos and UV-related immune suppression: a review. PMCID: PMC3970827.
- Polypodium leucotomos and UVB-induced DNA damage: a study. PMCID: PMC2774059.
- Polypodium leucotomos and collagen production: a study. PMCID: PMC4964402.
- Polypodium leucotomos and Langerhans cells: a study. PMID: 19388527.
