A miniature bunch of green grapes grows underwater. The beads belong to Caulerpa lentillifera, a green seaweed whose appearance makes its common name easy to remember. Look beyond that resemblance and another story emerges, one involving marine sugars and the way researchers study moisture, pigment and environmental stress. [S1]
Sea Grapes are also eaten as a nutrient-rich sea vegetable in parts of East and Southeast Asia, where they are valued for their minerals, vitamins and marine nutrients.
For skincare, the most interesting starting point is their polysaccharides: long chains of sugars, some carrying sulfate groups. Their molecular structure matters. In a 2023 study, researchers isolated a sulfated polysaccharide from Caulerpa lentillifera and found that it inhibited hyaluronidase, an enzyme that breaks down hyaluronic acid. Altering the polysaccharide’s size or removing sulfate groups reduced that activity. [S1]
Hyaluronic acid helps hold water within skin, so this enzyme research offers a useful lead for investigating moisture support. A separate 2024 study also documented antioxidant activity in sea grape polysaccharide preparations, adding another reason to look closely at these marine molecules. [S1] [S2]
The skin-focused research becomes particularly interesting when environmental stress enters the picture. In a 2026 study, an ethyl acetate extract of sea grapes was tested in UV-exposed human keratinocytes and mouse fibroblasts. It improved cell survival, reduced the accumulation of reactive oxygen species and activated an antioxidant-response pathway involving Nrf2. [S3]
The researchers also observed lower expression of MMP1 and MMP3, enzymes involved in tissue-matrix breakdown, alongside increased procollagen synthesis. These cell-based findings help explain interest in the ingredient’s potential relevance to skin structure and elasticity. [S3]
There is a separate thread of research on pigmentation. A 2025 study found that a sea grape polysaccharide preparation reduced melanin production and tyrosinase activity in a human melanoma cell model used to investigate pigment biology. This adds another specific research direction to the ingredient’s skincare story. [S4]
Other studies add detail to the picture. An extract reduced inflammatory messengers in stimulated mouse macrophages, providing mechanistic evidence for further anti-inflammatory research. Antibacterial testing has also found activity in selected sea grape preparations, with results varying considerably by extraction method. These are distinct experiments, each examining a different part of the ingredient’s potential. [S5] [S6]
For Earth & Halo, the appeal is this breadth of marine chemistry: moisture-related mechanisms, antioxidant activity and questions about how skin responds to stress. Together, these findings offer a rationale for exploring moisture and barrier-supportive formulations. Demonstrating those effects in a finished product means testing that particular formula.
Sea grape extract is one part of Blue Crystalline’s wider formulation, bringing this marine ingredient into our approach to daily skincare. Discover its place in Blue Crystalline 30 ml, our One-Step Skincare serum.
