BACKGROUND: Nicotinamide (NAM) and Polypodium leucotomos extract (PL) have demonstrated photoprotective effects, but their role in preventing UVA-induced DNA damage in humans remains unclear. RESULTS: Both NAM and PL increased MED by 26%. Neither treatment reduced UVA-induced TT-dimers in skin (NAM: p = 0.
Relevant if you're working with niacinamide, pha for rosacea.
If you're targeting rosacea, this research supports adding niacinamide to your AM/PM routine. Effective concentration range: 26% based on this study. Timeline to expect: 4 weeks based on study duration.
If you're targeting rosacea, this research supports adding pha to your AM/PM routine. Effective concentration range: 26% based on this study. Timeline to expect: 4 weeks based on study duration.
Translated from this study's findings, not a personal prescription. Pair with your existing protocol and your practitioner's guidance.
1. Photochem Photobiol Sci. 2026 May;25(5):845-852. doi: 10.1007/s43630-026-00884-2. Epub 2026 Mar 16. Changes in ultraviolet a radiation-induced thymidine dimers and erythema after oral nicotinamide or polypodium leucotomos extract in healthy volunteers: a randomized intraindividual trial.
1. Photochem Photobiol Sci. 2026 May;25(5):845-852. doi: 10.1007/s43630-026-00884-2. Epub 2026 Mar 16. Changes in ultraviolet a radiation-induced thymidine dimers and erythema after oral nicotinamide or polypodium leucotomos extract in healthy volunteers: a randomized intraindividual trial. Faisal A(1)(2), Lerche CM(3)(4), Douki T(5), Philipsen PA(3), Pihl C(3), Gregersen T(3), Granborg JR(3), Bjerring P(6), Haedersdal M(3)(7), Wiegell SR(6)(3)(7). Author information: (1)Department of Dermatology, Aalborg University Hospital, Moelleparkvej 4, Aalborg, 9000, Denmark. aheen@rn.dk. (2)Department of Dermatology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark. aheen@rn.dk. (3)Department of Dermatology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark. (4)Department of Pharmacy, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark. (5)Université Grenoble Alpes, CEA, CNRS, Grenoble-INP, IRIG/SyMMES Grenoble, Grenoble, France. (6)Department of Dermatology, Aalborg University Hospital, Moelleparkvej 4, Aalborg, 9000, Denmark. (7)Department of Clinical Medicine, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark. BACKGROUND: Nicotinamide (NAM) and Polypodium leucotomos extract (PL) have demonstrated photoprotective effects, but their role in preventing UVA-induced DNA damage in humans remains unclear. OBJECTIVE: To evaluate the effects of oral NAM and PL on UVA-induced erythema and thymidine dimer (TT-dimer) formation. METHODS: In this intraindividual trial, 50 healthy volunteers (phototypes I-III) were randomized (1:1) to receive either NAM (2000 mg daily) or PL (Heliocare Advanced: 480 mg daily) for 30 days. UVA-induced erythema, assessed by minimal erythema dose (MED), and TT-dimers, quantified in urine and skin biopsies, were measured before and after treatment with NAM or PL. RESULTS: Both NAM and PL increased MED by 26%. With a median MED of 27.7 J/cm² (13.4-51.1 J/cm²) pre-NAM and 34.8 J/cm² (13.4-62.5 J/cm²) post-NAM (p = 0.0008). And A median MED of 27.7 J/cm² (13.4-51.1 J/cm²) pre-PL and 34.8 J/cm² (16.4-62.5 J/cm²) post-PL (p = 0.0002). Neither treatment reduced UVA-induced TT-dimers in skin (NAM: p = 0.15; PL: p = 0.15) or urine (NAM: p = 0.89; PL: p = 0.30). LIMITATIONS: NAM and PL were not administered during the urine collection-period, which limited the assessment of the treatment's effect after radiation. CONCLUSION: UVA-induced erythema was significantly reduced by PL and NAM, but neither had measurable effects on TT-dimer induction. Further research should investigate the relation between these findings and the chemopreventive effect of NAM and PL on skin cancer. © 2026. The Author(s). DOI: 10.1007/s43630-026-00884-2 PMID: 41838346 [Indexed for MEDLINE] Conflict of interest statement: Declarations. Conflict of interest: Faisal A, Philipsen PA, Lerche CM, Douki T, Pihl C, Gregersen T, Granborg JR, Bjerring P, Haedersdal M, and Wiegell SR have no conflicts of interest to disclose. Ethical approval: Reviewed and approved by Regional Committee on Health Research Ethics, and Danish Health and Medicine Authority (approval # N-20240048) and The Danish Data Protection Agency. Informed consent: None.
Original source →Wounds continue to represent a significant public health challenge globally. In recent years, Astragalus mongholicus Bunge, a traditional Chinese botanical drug utilized for wound treatment, has garnered increasing research attention. However, the therapeutic efficacy and safety of this natural botanical drug on wound healing remain poorly understood.
Recent preclinical studies have shown that nicotinamide adenine dinucleotide (NAD+) plays a critical role in molecular mechanisms of axon degeneration, and reductions in NAD+ levels are associated with axonal degeneration. Nicotinamide riboside (NR) is a safe and widely available pyridine-nucleoside form of vitamin B3 and is an NAD+ precursor. To investigate if oral supplementation of synthetic NR can act as a therapeutic agent to prevent degeneration of small somatic sensory axons innervating the skin or promote regeneration of these same fibers in humans, we utilized a validated experimental model of cutaneous nerve degeneration and regeneration and conducted a placebo-controlled, double-blinded Phase 2 study.
Friedreich's ataxia is a rare, chronic, progressive, neurodegenerative condition affecting multiple organ systems, including neurological, musculoskeletal, cardiac, and endocrine systems, and is marked by low cardiopulmonary fitness. We tested the effect of exercise and NAD+ precursor supplementation with nicotinamide riboside, which have each shown benefits in animal and early clinical studies, on cardiopulmonary fitness in individuals with Friedreich's ataxia. This 12-week, outpatient, phase 2, single-site (Children's Hospital of Philadelphia, Philadelphia, PA, USA), randomised, 2 × 2 factorial clinical trial recruited individuals aged 10-40 years with an ejection fraction of 45% or greater who were able to exercise.
This information is for educational purposes only and is not medical advice. Individual results vary. Consult a qualified dermatologist or healthcare professional for medical concerns. Full disclaimer →