When it comes to skincare, not everything “natural” is truly nourishing—especially if you have sensitive, mature, or compromised skin. While essential oils may be trending in "clean" beauty, they often do more harm than good.

At Beleza by Z, we take a radically different approach: rooted in skin biology, and guided by ancient wisdom. Here's why we intentionally leave essential oils out of our formulas—and why our minimalist, tallow-infused skincare is designed to support, not stress, your skin barrier.  Let's start with some facts:

1. Oils Are Occlusives: Big Molecules = Not Hydrators

Oils are made up of large molecules. No matter how premium the oil—rosehip, marula, tallow, emu, squalene, squalane, castor, olive, jojoba, coconut, or argan—it doesn’t actually hydrate your skin. All oils (except for essential oils) are occlusives, meaning they act as a protective barrier on the skin’s outermost layer to lock in existing moisture. But if your skin is dehydrated to begin with, an oil alone won’t solve the problem. In fact we don't recommend using any type of pure oil or heavy emollients (on the face) since this can trigger or worsen perioral dermatitis, a skin condition that causes red, inflamed skin around the mouth and nose.  Real hydration comes from humectants—ingredients that attract and bind water to the skin. Think: aloe vera, hyaluronic acid, beta glucan, etc. In order to moisturize, your skincare product must contain water or water-binding ingredients, like our Bio Lipids Tallow Moisturizer SPF 30. So no, it's not just another oil in bougie packaging. We Promise. 

2. Essential Oils: Small Molecules = Big Risk

All essential oils are composed of low molecular weight compounds that easily penetrate the skin barrier. This might sound beneficial—but it’s not. These natural compounds are actually volatile plant defense chemicals (known as phytotoxins or allelochemicals) designed to repel predators. When applied to human skin, especially if it’s sensitive, aging, or compromised, they can trigger:

• Inflammation
  
• Allergic reactions
  
• Chemical burns
  
• Hormonal disruption

Even when “diluted” in carrier oils, these small, reactive molecules can disrupt the endocrine system and exacerbate skin conditions like acne, rosacea, eczema. Essential oils are also among the top allergens in natural and organic skincare—even when certified organic. 

3. Why We Use Suet-Derived Tallow Exclusively

Rather than using conventional store-bought tallow or seed oils that go rancid quickly, we use one emollient across our entire line: highly purified suet-derived tallow from grass-fed cattle. Why? Because cholesterol, along with other lipids, plays a key role in maintaining youthful, radiant skin—especially for women navigating hormone changes, inflammation, or skin sensitivity. Our skin’s outer layer, the stratum corneum, contains cholesterol, which helps retain moisture and protect against environmental damage. It’s not just a building block for healthy cells; it also fortifies the skin barrier, retains moisture, and supports overall skin function to keep it from becoming dry, flaky, or irritated. Many skin care brands recognize this fact and incorporate synthetic or plant-based cholesterol into their formulas. However, there’s a crucial difference between what you’ll find in Beleza by Z. On a molecular level and despite being naturally derived, plant-based versions of cholesterol are not identical to the cholesterol in human skin, which is chemically closer to animal-derived cholesterol. As a result, modified versions are sometimes less effective, especially for those with sensitive or reactive skin since it’s often paired with more preservatives and stabilizers, which can further irritate the skin. Aside from biocompatibility, tallow is rendered from whole-animal suet, upcycled as part of a nose-to-tail commitment to sustainability. It's luxury without waste—pure, purposeful, and effective. We purify our tallow in small batches to remove all impurities and scent, resulting in a silky, neutral base that delivers visible results without the use of texture enhancing silicones, mineral oil, or irritating fragrances. 

4. Formulated with Intention, Grounded in Skin Biology

We don’t follow trends. Our mission is to redefine luxury skincare through sustainable and minimalist formulations that blend ancient wisdom with cutting-edge innovation. We are dedicated to crafting products that support holistic wellness, empower informed choices, and deliver exceptional results for all skin types, especially sensitive skin. 

To learn more about naturally occurring defense chemicals in plants, we encourage exploring a combination of botany, phytochemistry, and toxicology resources. Educated consumers are empowered consumers. Here are some high quality academic, textbook, and online resources to help guide your discovery:

Textbooks & Academic References

Botany & Plant Biology

1. "Botany for Gardeners" by Brian Capon – Introductory but useful for understanding plant structures and survival mechanisms.

2. "Plant Systematics" by Michael G. Simpson – Discusses plant families and secondary metabolite patterns.

3. "Plant Biology" by Linda E. Graham et al. – A foundational text that covers plant physiology and biochemical adaptations.

Phytochemistry & Plant Defense Compounds

1. "Medicinal Natural Products: A Biosynthetic Approach" by Paul M. Dewick – Excellent for learning biosynthesis pathways of plant defense chemicals.

2. "Introduction to Plant Physiology" by William G. Hopkins & Norman P. A. Hüner – Includes sections on plant chemical defenses.

3. "Phytochemical Dictionary: A Handbook of Bioactive Compounds from Plants" edited by Harborne, Baxter & Moss – A reference book lis

Toxicology / Plant Defense in Human Context

1. "Toxic Plants of North America" by Burrows & Tyrl – Excellent for identifying toxic plant species and their compounds.

2. "Handbook of Poisonous and Injurious Plants" by Nelson, Shih, and Balick – For toxic plants and their effects on humans and animals.

University-Level Courses & Lecture Materials

MIT OpenCourseWare – Chemistry of Biomolecules:

https://ocw.mit.edu – Search for organic chemistry and plant biochemistry courses.

Coursera & edX Courses:

Plant Bioinformatics or Plant Biochemistry by Wageningen University or University of Illinois.

Medicinal Plants courses often cover defense mechanisms.

Research Databases & Journals

1. PubMed – Search terms like "plant secondary metabolites" or "allelopathic chemicals".

2. Google Scholar – Excellent for reviewing primary literature and citations.

3. ScienceDirect & SpringerLink – Hosts journals on plant physiology and phytochemistry.

4. Journal of Chemical Ecology – Covers chemical interactions between plants and the environment.

Online Resources & Databases

Dr. Duke’s Phytochemical and Ethnobotanical Databases (USDA): https://phytochem.nal.usda.gov/phytochem/search

Offers a searchable database of known plant chemicals and their bioactivities.

Kew Science – Plants of the World Online:

https://powo.science.kew.org

For botanical classification and links to medicinal or toxic properties.

Royal Botanic Gardens, Kew – Useful Plants & Fungi:

A great place to research ethnobotany and traditional plant use, including defense roles.