The rating system we've been using to avoid breakouts was created in the 1970s using rabbit ears. It's time we talked about this.
If you've ever stood in a skincare aisle squinting at ingredient lists, trying to remember which oils are "safe" and which will supposedly turn your face into a minefield of clogged pores, you're not alone. The concept of comedogenic ratings has become skincare gospel, repeated so often that we've stopped questioning where it came from or whether it actually means anything.
Here's the uncomfortable truth: the comedogenic rating system is fundamentally flawed, and for mature skin, it's often completely irrelevant. Yet it continues to dictate product choices, particularly when it comes to ingredients like beef tallow, which carries a rating of 2-3 on a 0-5 scale and therefore gets dismissed as "pore-clogging" without further investigation.
Let's examine what these ratings actually measure, why they're misleading, and what you should be paying attention to instead.
The Rabbit Ear Problem
The comedogenic rating system was developed in the 1970s by Dr. Albert Kligman and Dr. James Fulton through a series of studies that sound reasonable until you hear the methodology: they applied various substances to the inner ears of albino rabbits, then examined the tissue for signs of clogged follicles.[1]
The issues here are numerous. First, rabbit ear skin is dramatically different from human facial skin in terms of follicle density, sebum production, and structural composition. Second, the studies used pure, undiluted ingredients applied repeatedly in concentrations far exceeding what you'd encounter in a formulated product. Third, and perhaps most significantly, they were testing for the formation of comedones (blackheads and whiteheads), not evaluating how these ingredients behave in the context of actual skincare formulations with multiple ingredients that interact with each other.[2]
Despite these limitations, the ratings became codified in dermatological literature and subsequently in popular consciousness. Coconut oil got a 4 (highly comedogenic). Olive oil got a 2 (moderately comedogenic). Jojoba oil, interestingly, got a 2 as well, despite being widely recommended for acne-prone skin by dermatologists who apparently haven't read the original studies they're citing.
The system was never validated for human facial skin, never updated to reflect advances in our understanding of skin physiology, and yet it persists as received wisdom.
Context Is Everything (And the Ratings Ignore It)
Here's what the comedogenic rating system doesn't account for: formulation, concentration, skin type, skin barrier health, other ingredients in the product, application method, or individual skin chemistry.
A single ingredient rated "3" might be perfectly fine in a product where it constitutes 5% of the formulation, combined with ingredients that enhance absorption and prevent surface buildup. That same ingredient at 100% concentration, applied daily in occlusive conditions (like, say, to a rabbit's inner ear), might indeed cause congestion.
Consider the paradox of petrolatum, rated 0 (non-comedogenic). It's pure occlusion, creating a barrier that prevents transepidermal water loss. For mature skin with a compromised barrier, this can actually prevent congestion by supporting the skin's natural desquamation process. For very oily skin with overactive sebaceous glands, it might trap sebum and contribute to breakouts. The rating tells you nothing about this nuance.[3]
Beef tallow sits in a similar category. Its rating of 2-3 suggests moderate comedogenic potential, but this doesn't reflect how it actually behaves on human skin, particularly mature skin. The fatty acid profile that makes it similar to human sebum means it tends to integrate into the skin barrier rather than sitting on the surface. For skin that's producing less sebum naturally (which is most women over 50), this supplementation of lipids rarely causes congestion.[4]
Your Skin at 55 Is Not Your Skin at 25
This might be the most important point: comedogenic ratings were primarily developed with young, acne-prone skin in mind. The skin physiology of a teenager with hormonally-driven breakouts is fundamentally different from the skin of a post-menopausal woman.
After menopause, sebum production drops significantly. The average 60-year-old produces about 40% of the sebum she did at 20.[5] The concern with "pore-clogging" is primarily about excess sebum getting trapped in follicles. When you're not producing excess sebum, this mechanism is far less relevant.
What becomes more relevant is barrier function. Mature skin has a compromised lipid barrier, higher transepidermal water loss, and slower cell turnover.[6] The ingredients that support barrier repair (which tend to be lipid-rich and therefore often rated as "comedogenic") become more beneficial than problematic.
This doesn't mean mature skin can't experience congestion or breakouts. It absolutely can. But the causes are typically different: barrier disruption leading to compensatory oil production, hormonal fluctuations, reaction to active ingredients, or fungal overgrowth rather than simple "pore-clogging" from topical oils.
The Barrier Function Paradox
Here's something that sounds counterintuitive but is well-established in dermatological research: supporting skin barrier function with occlusive lipids can actually reduce breakouts in some people, even though those lipids might be rated as "comedogenic."
When your skin barrier is compromised, your skin compensates by producing inflammatory mediators and sometimes increasing sebum production in an attempt to protect itself.[7] This creates a cycle where damaged barrier leads to more oil, which leads to congestion, which leads to more barrier damage.
Applying appropriate lipids (whether that's tallow, squalane, or ceramides) can interrupt this cycle by giving the barrier what it needs to repair itself. Once the barrier is functioning properly, it can regulate sebum production more effectively and maintain normal desquamation (the shedding of dead skin cells that prevents pore blockage).[8]
This is why many dermatologists recommend seemingly "heavy" occlusives for patients dealing with breakouts secondary to barrier damage from overuse of actives like retinoids or acids. The occlusion isn't causing more breakouts; it's preventing them by restoring normal barrier function.
When Tallow Actually IS Wrong for Your Skin
In the interest of being genuinely useful rather than promotional, let's talk about when beef tallow is legitimately not appropriate, regardless of what the comedogenic rating says.
Fungal acne (Malassezia folliculitis): This is a specific condition where yeast overgrowth in hair follicles causes acne-like breakouts. Malassezia feeds on certain fatty acids, particularly oleic acid, which is abundant in beef tallow. If you have fungal acne (typically small, uniform bumps that itch), tallow will make it worse. The comedogenic rating is irrelevant here; it's about the specific fatty acid profile.[9]
Very oily skin with no barrier issues: If you're one of the rare mature women still producing abundant sebum and your skin barrier is healthy, adding more lipids may be unnecessary. You don't need tallow; you need different support.
Active hormonal acne: If you're experiencing hormonally-driven breakouts (particularly cystic acne along the jawline), this is an internal issue that topical lipids won't solve and might exacerbate by adding more oil to an already oily situation.
Sensitivity to beef products: Some people have genuine sensitivities to animal-derived ingredients. This has nothing to do with comedogenicity and everything to do with individual immune response.
The point is that these are specific, identifiable contraindications, not vague fears based on an outdated rating system.
A Better Approach: Patch Testing and Observation
Rather than relying on comedogenic ratings to make decisions, here's a more useful protocol:
1. Assess your actual skin condition. Are you dealing with dryness, barrier damage, and sensitivity? Or active congestion with visible sebum production? These require different approaches.
2. Patch test properly. Apply the product to a small area (behind the jaw is ideal) for 3-5 days. If you're going to react, you'll typically know within this timeframe.
3. Introduce gradually. Start with application every other night, only on areas that need it most (avoiding any active breakouts). Observe for two weeks.
4. Pay attention to the right signs. Small whiteheads within 24-48 hours suggest congestion. Gradual improvement in texture and hydration with no new breakouts suggests the product is working.
5. Adjust based on results, not ratings. Your skin's response is infinitely more informative than what happened to rabbit ears in 1979.
The Larger Conversation
What's frustrating about the persistence of comedogenic ratings isn't just that they're scientifically questionable. It's that they've created a culture of fear around perfectly good ingredients, while simultaneously giving people false confidence in ingredients rated as "safe" that might be completely wrong for their skin.
Mature skin doesn't need you to be afraid of oils and lipids. It needs you to understand what's actually happening with your barrier function, your sebum production, and your individual skin chemistry. The goal isn't to avoid everything that might theoretically cause a problem; it's to give your skin what it needs to function properly.
Beef tallow's comedogenic rating tells you almost nothing useful about whether it will work for your 55-year-old face. Your skin's response over two weeks tells you everything.
References
- Fulton, J. E., et al. "Comedogenicity of Current Therapeutic Products, Cosmetics, and Ingredients in the Rabbit Ear." Journal of the American Academy of Dermatology 10.1 (1984): 96-105.
- Morris, W. E. "A Functional Approach to Comedogenesis." Journal of the Society of Cosmetic Chemists 21 (1970): 169-178.
- Draelos, Z. D. "The Effect of Petrolatum on the Skin Barrier Function." Journal of Cosmetic Dermatology 17.5 (2018): 617-622.
- Rawlings, A. V., et al. "Stratum Corneum Moisturization at the Molecular Level: An Update in Relation to the Dry Skin Cycle." Journal of Investigative Dermatology 104.6 (1994): 1096-1101.
- Jacobsen, E., et al. "Age-Related Changes in Sebaceous Wax Ester Secretion Rates in Men and Women." Journal of Investigative Dermatology 85.5 (1985): 483-485.
- Ghadially, R., et al. "The Aged Epidermal Permeability Barrier: Structural, Functional, and Lipid Biochemical Abnormalities in Humans and a Senescent Murine Model." Journal of Clinical Investigation 95.5 (1995): 2281-2290.
- Elias, P. M., et al. "Basis for the Barrier Abnormality in Atopic Dermatitis: Outside-Inside-Outside Pathogenic Mechanisms." Journal of Allergy and Clinical Immunology 121.6 (2008): 1337-1343.
- Proksch, E., et al. "Skin Barrier Function, Epidermal Proliferation and Differentiation in Eczema." Journal of Dermatological Science 43.3 (2006): 159-169.
- Rubenstein, R. M., et al. "Malassezia (Pityrosporum) Folliculitis." Journal of Clinical and Aesthetic Dermatology 7.3 (2014): 37-41.