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Polypodium leucotomos (Fernblock)
An oral fern extract (Fernblock) studied for skin photoprotection. The honest verdict: small randomized trials show it modestly adds to sunscreen and speeds melasma improvement, but it is an ADJUNCT to sunscreen, not a replacement.
What the evidence says
Polypodium Leucotomos doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality randomised trials published 2006–2026 with a typical study size of 40 participants.
Based on 19 studies · 13 RCTs · 40 total participants
Confidence
Moderate confidenceBy outcome
Small randomized trials show oral fern extract adds to sunscreen for photoprotection and accelerates melasma improvement, but the evidence base is limited and adjunct-only, keeping it Emerging.
No trials currently enrolling · 6 completed on ClinicalTrials.gov
1 of the completed trials have posted results
Registered trials show research momentum for Polypodium Leucotomos, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Oct 2026
Polypodium leucotomos is a tropical fern whose leaf extract (Fernblock) has antioxidant and anti-inflammatory effects that reduce UV-induced skin damage from the inside.
Randomized trials show oral PLE improves photoprotection on top of topical sunscreen and accelerates melasma improvement when combined with hydroquinone and SPF50. It's also used adjunctively for photodermatoses (e.g. polymorphic light eruption) and vitiligo.
Evidence is mostly small trials, and — critically — it is an ADJUNCT to sun protection, not a substitute for sunscreen or sun avoidance. Generally well tolerated.
Scavenges UV-induced reactive oxygen species, reducing DNA/skin damage.
Reduces UV-induced inflammatory mediators and pigment changes.
How Polypodium Leucotomos works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Limited data — use only if advised.
Keep using sunscreen — PLE is an adjunct, not a replacement.
No significant documented drug interactions. This possible interaction has not been individually evaluated for this supplement; its likelihood and severity are unknown. If you take an anticoagulant or antiplatelet medicine, ask a pharmacist or prescriber before using this product. Do not stop or change prescribed medicines based on this notice.
Tip: Take with food
Tip: Reduce dose
Polypodium Leucotomos has an evidence score of 4.5/10 — emerging evidence based on 19 indexed studies. An oral fern extract (Fernblock) studied for skin photoprotection. The honest verdict: small randomized trials show it modestly adds to sunscreen and speeds melasma improvement, but it is an ADJUNCT to sunscreen, not a replacement. Representative study: PMID 39804624.
The commonly studied dose of Polypodium Leucotomos is 240-480mg oral Polypodium leucotomos extract daily (often split, dosed before sun exposure) (a typical label dose, no cited trial of this supplement alone states a dose). Individual needs vary — start at the lower end of the range and adjust based on how you respond.
The best time to take Polypodium Leucotomos is in the morning. Taking it with food is preferred. Often taken in the morning and/or before sun exposure; consistency matters for pigment goals.
Polypodium Leucotomos is generally well-tolerated and considered safe for most healthy adults at recommended doses. Reported side effects include mild GI upset, itching/headache. How often they occur is not established for all of them. Use caution if any of these apply to you: Allergy to ferns; Pregnancy/breastfeeding (limited data).
Aged Garlic Extract
Likely helpsOdorless garlic extract with evidence for blood pressure and cardiovascular markers, and one trial reporting milder colds and flu.
Curcumin
Probably helpsTurmeric's active compound that modulates NF-kB inflammatory pathways — supports mood, joint health, and post-exercise recovery.
Andrographis
Likely helpsStudied for comfort and symptom duration during upper-respiratory infections when taken at onset — also supports liver health.
Ginger Extract
Likely helpsGingerols and shogaols reduce nausea, accelerate gastric emptying, and provide systemic anti-inflammatory benefits.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 19 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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