Clinical study examines rosemary and grapefruit extract formulation for skin health support after UV exposure

In May 2025, nutraceutical company Monteloeder, a subsidiary of Suannutra SA, announced results from a clinical study¹ examining the effect of Nutroxsun on skin health and appearance. The formulation is a combination of (Rosmarinus officinalis) and grapefruit (Citrus paradise) extracts and intended to support skin from exposure to external stressors such as UV radiation. As noted in the study’s abstract, sun exposure can cause oxidative stress, inflammation, and collagen degradation.

“Nutroxsun was developed as a dietary solution to support the skin’s natural defense mechanisms in response to UV-induced oxidative stress,” stated Mariana Ortega, science marketing manager of Suannutra, in the press release. “It acts from within to help maintain skin health when exposed to environmental aggressors. Rosemary and grapefruit extracts contain phenolic compounds that work synergistically to help neutralize free radicals generated by UV exposure. These effects are relevant to both short-term/immediate responses, such as redness, and long-term factors associated with visible signs of photoaging, including collagen and elastin changes.”

This study measured the efficacy of Nutroxsun for photoprotective, anti-photoaging, and anti-redness support. The in vivo portion, which was a placebo-controlled, randomized, crossover study, involved 20 participants receiving two doses, 100 and 250 mg of Nutroxsun, or a placebo, then skin redness and recovery was assessed 24 hours after UV exposure.

“Skin redness are the most noticeable and immediate inflammatory reaction to solar radiation,” explains Nuria Caturla, chief R&D office at Monteloeder. “It usually appears 3–5 hours after exposure and peaks at 12–24 hours, fading gradually over 72 hours.”

Results from the supplementation included a reduction in reactive oxygen species (ROS) levels and proinflammatory compounds, accelerated recovery from redness, and a dose-dependent countering of matrix metalloproteinases (MMP). Increased activity of MMP enzymes accelerates collagen breakdown. Reduction in redness was observed as early as 24 hours with the individuals taking the 250 mg dose, and after 25 hours for those taking the 100 mg dose.

“The results from the present study reinforce and expand on previous evidence supporting Nutroxsun’s role in helping improve skin health and appearance when exposed to UV-related stressors,” added Caturla. “Rosemary extracts have been shown to help slow down collagen degradation further highlighting their potential to support dermal structure and resilience. Grapefruit flavones have been studied for their role in counteracting UVB-induced oxidative effects that may impact collagen integrity helping protect the skin by stopping UVB rays from breaking down collagen.”

Reference

1. Navarro, P.; Castillo, J.; Jones, J.; García, A.; Caturla, N. Skin Photoprotection and Anti-Aging Benefits of a Combination of Rosemary and Grapefruit Extracts: Evidence from In Vitro Models and Human Study. Int. J. Mol. Sci. 2025, 26(9), 4001. DOI: 10.3390/ijms26094001