Rhizopus/Borago Officinalis Seed Oil Ferment Filtrate: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 30, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Rhizopus/Borago Officinalis Seed Oil Ferment Filtrate?

Rhizopus/Borago Officinalis Seed Oil Ferment Filtrate is a fermented extract made from borage seed oil. Borage, or Borago officinalis, is a flowering herb whose seeds are naturally rich in gamma-linolenic acid and other fatty acids that help keep skin supple. To create the filtrate, manufacturers let the Rhizopus fungus ferment borage seed oil in a controlled setting. During fermentation the microorganism breaks down large oil molecules into smaller components and also produces new skin-friendly compounds such as peptides, enzymes and sugars. The final liquid is then filtered to remove any solid residues, leaving a clear nutrient-packed solution.

The idea of using fermented plant oils in skincare has grown alongside the popularity of K-beauty, which champions fermentation for its ability to boost ingredient absorption and gentleness. Cosmetic chemists found that blending the time-tested benefits of borage oil with microbial fermentation gives a lighter feel and improved skin affinity compared with raw oil. Today this filtrate shows up in a range of leave-on and rinse-off products. You may spot it in hydrating sheet masks, daily moisturizers, lightweight anti-aging serums, barrier-support creams and soothing after-sun gels.

Rhizopus/Borago Officinalis Seed Oil Ferment Filtrate’s Cosmetic Benefits/Uses

This ingredient is classed as a skin-conditioning agent, which means its main role is to keep skin feeling smooth comfortable and healthy. The fermented compounds help replenish lipids, attract water and support the skin barrier, leaving the complexion soft and well-hydrated without a greasy residue.

Who Can Use Rhizopus/Borago Officinalis Seed Oil Ferment Filtrate

This ferment filtrate is generally friendly to all skin types. Dry or mature skin benefits from its lipid replenishing properties while sensitive skin often appreciates its gentle, lightweight feel. Oily and combination skin usually tolerate it well since fermentation reduces the heaviness typical of pure plant oils. If you have a history of fungal acne or very reactive skin you might want to introduce it slowly, as any fermented ingredient can occasionally disagree with an already unbalanced microbiome.

The ingredient is produced from plant seed oil with the help of a non-animal microorganism so it is suitable for vegans and vegetarians. Of course cruelty-free status depends on the final brand’s testing policies rather than the ingredient itself.

No data suggest that Rhizopus/Borago Officinalis Seed Oil Ferment Filtrate poses a specific risk for pregnant or breastfeeding women when used topically in cosmetic amounts. That said this is not medical advice and anyone who is expecting or nursing should clear every new skincare product with a healthcare professional first.

The filtrate is not known to cause photosensitivity so it will not make skin more vulnerable to sunlight. Normal daily sunscreen habits remain important for overall skin health. There are no other special lifestyle restrictions linked to this ingredient.

Potential Side Effects/Adverse Reactions

Reactions to topical Rhizopus/Borago Officinalis Seed Oil Ferment Filtrate differ from person to person. The points below outline potential side effects only and most users will not run into these issues when the ingredient is formulated and used as intended.

  • Mild redness or stinging
  • Itchiness or localized rash due to allergy
  • Clogged pores in very acne-prone skin
  • Fungal acne flare in individuals already prone to Malassezia overgrowth
  • Irritation from product contamination if the formula lacks adequate preservation

If you experience any uncomfortable reaction discontinue use and consult a medical professional.

Comedogenic Rating

Rating: 1/5 – The filtrate contains only trace amounts of the original borage seed oil, with most heavy triglycerides broken down or removed during fermentation and filtration. What remains is a lightweight mix of water-soluble nutrients and small lipid fragments that sit lightly on skin and rinse away easily. Because of this low oil load the ingredient is very unlikely to clog pores for most users. Those who are highly prone to acne or fungal breakouts can generally use it without issue, though individual reactions can vary. If the final formula pairs the filtrate with richer emollients the overall product could be more comedogenic so always consider the full ingredient list.

Summary

Rhizopus/Borago Officinalis Seed Oil Ferment Filtrate is primarily a skin conditioning agent that boosts hydration comforts dryness and strengthens the barrier. Fermentation splits bulky borage oil molecules into smaller skin-friendly components like peptides fatty acid fragments and polysaccharides which absorb more readily and leave a non-greasy finish.

While still a niche addition it is gaining traction in K-beauty inspired moisturizers serums and masks that promise a softer lightweight feel than straight plant oils. Brands looking for gentle vegan alternatives to conventional emollients often spotlight it on their labels.

Current data show a low risk profile with only rare reports of irritation or pore congestion. As with any new skincare ingredient it is smart to do a quick patch test when trying a product that contains this ferment filtrate to make sure your skin agrees with it.

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