According to a study, published in the International Journal of Molecular Sciences, an extract combination marketed as Nutroxsun significantly reduced UV-induced erythema (skin redness) after a single dose, with signs of recovery starting within 24 hours post-UV exposure.
Findings from the randomized controlled trial showed that supplementation inhibited the secretion of matrix metalloproteinases (MMP-1 and MMP-3), which degrade collagen and elastin, thereby helping preserve extracellular matrix integrity. In UV-irradiated fibroblasts (NHDFs), collagen and elastin secretion increased, counteracting UV-induced reductions. There was also a dose-dependent reduction of oxidative stress markers IL-1α, IL-6, and IL-8 in UVB-exposed keratinocytes.
Nutroxsun is manufactured by Spanish ingredient supplier Monteloeder by Suannutra, which funded the study.
Preventative and reparative effects
Nuria Caturla, PhD, chief R&D officer for Monteloeder and co-author on the new paper, said these findings expand the scope of Nutroxsun beyond prevention alone, confirming its dual potential as both a protective and reparative agent.
“One of the most remarkable results is that Nutroxsun significantly reduced UV-induced skin redness and accelerated recovery even without prior intake—demonstrating that the ingredient can support the skin not only preventively but also as a response strategy after sun overexposure,” she said.
“In addition, we deepened our understanding of its mechanism of action at the cellular level. The study shows that this protects against UV damage through a multi-targeted approach: It reduces reactive oxygen species (ROS), suppresses proinflammatory cytokines and preserves essential skin matrix proteins.”
She explained that the ingredient is meant to complement traditional photoprotection methods by providing a systemic layer of defense from within.
“It doesn’t replace sunscreens or topical antioxidants, it enhances them,” she said, noting that having a supplement that strengthens the skin’s resilience is a “game changer”, particularly since incidental sun exposure is at times unavoidable.
“With its clinically proven benefits, such as increased MED, reduced lipid peroxidation, improved elasticity and reduced wrinkle depth, it offers a compelling long-term solution to consumers seeking beauty-from-within strategies,” she added.
A synergistic sun-protective combination
The innovation is the result of 15 years of collaborative R&D with several universities and research centers to identify natural botanical compounds capable of providing systemic photoprotection.
“We started by screening a wide range of Mediterranean plant extracts—plants that naturally grow in high-UV environments and have evolved to produce photoprotective compounds as a survival strategy,” Caturla said.
“Through extensive in vitro testing, we observed that the combination of rosemary and grapefruit extracts offered not only strong individual efficacy but also remarkable complementary and synergistic effects.”
She highlighted that these extracts showed a unique and complementary antioxidant profile: “Rosemary contributes lipid-soluble polyphenols like carnosic acid, while grapefruit provides water-soluble flavones.”
“This dual solubility allows Nutroxsun to act across both aqueous and lipid cellular compartments—neutralizing reactive oxygen species (ROS), inhibiting lipid peroxidation, and preserving membrane integrity,” she explained.
Benefits are ‘not limited to fair skin’
Most of Monteloeder’s clinical research for this ingredient to date has focused on Fitzpatrick skin phototypes I to III and has demonstrated clear benefits such as increased MED and reduced UV-induced erythema, but the benefits are not limited to fair skin.
Caturla said that many of the mechanisms the ingredient targets, such as oxidative stress, inflammation and extracellular matrix degradation, affect all skin types, including the darker phototypes.
“Phototypes IV and above may have more natural melanin protection against UV-induced redness, but they are still susceptible to photoaging and especially to post-inflammatory hyperpigmentation, a common concern in these populations,” she said.
She added that a recent clinical study conducted using a finished product containing Nutroxsun in individuals with phototypes IV to VI showed a significant reduction in hyperpigmentation, which “reinforces its broader applicability as a photoprotective and skin-evening solution across diverse skin tones.”
The ingredient, which has already been commercially available in Japan for over 10 years, not only protects against the sun but preserves collagen and elastin and can be easily combined with actives like collagen peptides, hyaluronic acid or ceramides to create synergistic anti-aging solutions.
Source: International Journal of Molecular Sciences. doi: 10.3390/ijms26094001. “Skin Photoprotection and Anti-Aging Benefits of a Combination of Rosemary and Grapefruit Extracts: Evidence from In Vitro Models and Human Study”. Authors: P. Navarro et al.