Curly hair porosity: the scientific key to radiant locks

How your curls’ structure determines their ability to retain moisture and why it changes all the hair care rules

In a world where every curl has its own character, understanding hair porosity can be a true breakthrough for those with curly hair. This characteristic, invisible to the naked eye, not only determines how quickly curls absorb and lose moisture—it dictates the entire philosophy of curly hair care. From product selection to application techniques—everything depends on this fundamental property.

The secret in structure: why curly hair is unique

“Imagine hair as a three-layered structure, where the outer layer—the cuticle—works like a moisture regulation scale,” explains Dr. Alan J. Bauman, a certified trichologist and founder of Bauman Medical Group. “In curly hair, this structure inherently differs from straight hair, as the curls create an uneven distribution of the protective lipid layer.”

It is this structural uniqueness that makes the question of porosity particularly relevant for those with curls. Each curve of a curl is a potential “weak spot” where moisture can either penetrate inside or, conversely, leave the hair.

According to a study published in the Journal of Cosmetic Science, curly hair has, on average, 30% more variable cuticle structure compared to straight hair, which directly affects its ability to manage moisture.

Decoding porosity: low, medium, high

“Porosity is the hair’s ability to allow moisture to pass through the cuticle into the cortex and back,” explains Jenny Cho, a famous stylist whose clients regularly appear on fashion magazine covers. “Correctly determining the level of porosity can change the entire game in curly hair care.”

Low porosity is characterized by tightly closed cuticle scales that prevent moisture penetration. Such hair takes longer to dry, often looks smoother, but requires a special approach for deep hydration.

“Medium porosity hair is the golden middle,” continues Cho. “It retains moisture well, is easier to style, and generally looks healthiest. But over time or under external factors, medium porosity can change.”

High porosity hair quickly absorbs moisture but loses it just as quickly. Often this is the result of damage from thermal or chemical exposure, which manifests as brittleness, dryness, and a tendency to tangle.

Scientific basis: a molecular view of porosity

According to research by Dr. Wendy Roberts, a dermatologist specializing in hair health, porosity is directly related to the pH balance of hair.

“At the molecular level, the hair cuticle responds to changes in the pH environment,” explains Dr. Roberts. “An alkaline environment opens the cuticle scales, increasing porosity, while an acidic environment promotes their closure, reducing porosity.”

This explains why rinsing hair with acidic solutions, such as apple cider vinegar, can temporarily reduce porosity, sealing the cuticle and making hair smoother and shinier.

A 2022 study conducted at the Massachusetts Institute of Technology found that curly hair has a unique pattern of keratin protein distribution, which directly affects its porosity. This helps explain why some curls retain moisture more effectively than others even with identical care.

Determining your type: home tests and professional diagnostics

“A simple porosity test can be done at home,” advises Takisha Sturdivant, founder of A Cut Above salon in New York. “Take a clean hair strand and place it in a glass of water. If it sinks quickly, you have high porosity; if it hovers in the middle, medium; and if it stays on the surface, low.”

Another method is to run your fingers along a hair strand from tip to root. “If you feel roughness, this indicates high porosity, as the cuticle scales are raised,” explains Sturdivant.

However, for more accurate diagnostics, it’s worth consulting a trichologist who, using microscopic examination, can not only determine porosity but also identify other structural features of the hair.

Moisturizing strategies: science in action

Depending on the porosity of curly hair, moisturizing strategies should radically differ.

For low porosity hair, Amica Williams, a cosmetic chemist and creator of a curly hair product line, recommends: “Use heat to open the cuticle—for example, steam treatments or warm oil masks. Preference should be given to light oils such as almond or jojoba, which more easily penetrate the dense cuticle.”

Those with medium porosity hair are luckier: “Such hair responds well to most moisturizing products,” says Williams. “The key is maintaining balance between moisturizing and nourishing without overloading the hair with heavy ingredients.”

High porosity curls require a special approach. “Here, the principle of ‘sealing’ moisture works,” explains Vernon François, a famous stylist working with Hollywood stars. “After moisturizing, use products with oils and fatty alcohols that will create a barrier and prevent moisture loss.”

Molecular heroes: ingredients that really work

“To understand the effectiveness of moisturizing products, they must be considered at the molecular level,” asserts Dr. Rosemary Gladstar, a biochemist and consultant to several leading hair care brands.

For low porosity hair, ideal ingredients include: aloe vera (molecules small enough to penetrate the dense cuticle), glycerin in low concentrations, and hydrolyzed proteins of small size.

Medium porosity hair benefits from: shea butter, panthenol (provitamin B5), hyaluronic acid, and medium molecular weight proteins.

High porosity hair needs: castor oil (forms a protective film), coconut oil (especially before washing to protect from swelling in water), ceramides, cupuaçu oil, and heavier proteins that fill damaged areas.

Revolutionary formulas: what experts are looking for

“Innovative formulas for curly hair today consider porosity as a key factor,” says Brianna Krapivkina, a formulation chemist and cosmetic product developer. “We’re seeing the emergence of ‘smart’ polymers that interact differently with hair of varying porosity—literally adapting to the needs of each curl.”

The latest technologies include microencapsulation of active ingredients that are released gradually throughout the day, responding to changes in temperature and humidity of the surrounding environment.

“Products with adaptive pH that changes depending on the condition of the hair cuticle are also appearing,” adds Krapivkina. “This allows the same product to work differently on hair sections with varying porosity, which is especially relevant for curly hair, where porosity can vary even within a single curl.”

From theory to practice: moisturizing routines for different porosity types

Sophie Hilton, founder of Neville Hair & Beauty salon in London, shares specific recommendations:

For low porosity hair:

• Start with pre-washing with warm water to open the cuticle
• Use light conditioners without heavy oils and silicones
• Apply leave-in products to damp hair
• Experiment with the LOC technique (liquid-oil-cream) in a lighter version

For medium porosity hair:

• Balance moisturizing and protein products
• Apply the classic LOC technique (liquid-oil-cream)
• Deep condition once every 2-3 weeks
• Use serums with hyaluronic acid for additional moisture

For high porosity hair:

• Start with a pre-oil treatment before washing
• Use shampoos with gentle cleansing agents
• Apply the LCO technique (liquid-cream-oil)
• Deep condition weekly
• Finish care with oils that seal the cuticle

The climate factor: how the environment affects working with porosity

“Hair porosity is a dynamic characteristic that responds to changes in the environment,” explains Professor Tom Johnson, a climatologist and consultant in the beauty industry. “High air humidity can temporarily increase hair porosity, while dry climates can exacerbate problems of high porosity hair.”

According to research conducted at L’Oréal Research & Innovation laboratory, in conditions of humidity above 70%, even low porosity hair begins to absorb moisture from the air, which can lead to frizz and loss of curl definition.

“In conditions of extreme climate changes, it’s worth adapting your routine,” advises Johnson. “In particularly humid conditions, focus on anti-frizz ingredients and cuticle-sealing finishers, and in dry climates, increase the frequency of deep conditioning.”

Special case: the transition period from chemically processed to natural hair

“Porosity is especially important to consider during the transition from chemically straightened to natural curly hair,” emphasizes Nikki Walton, bestselling author on curly hair and founder of the Natural Hair Revolution movement.

“During this period, there are simultaneously areas with different porosity on the head—usually damaged ends have high porosity, while newly grown hair may have low or medium,” explains Walton. “This requires a segmented approach to care, where different sections of hair receive different products.”

The future of personalization: technologies at the service of porosity

“We stand on the threshold of a revolution in understanding and working with hair porosity,” asserts Lucas Alexander, founder of the technology startup HairTech, which is developing portable hair structure scanners.

“Imagine a smartphone-sized device that can instantly analyze your hair’s porosity and select the perfect combination of products,” describes Alexander. “Or smart product bottles that adapt their formula in real-time, responding to changes in the environment and the condition of your hair.”

According to McKinsey Global Institute forecasts, by 2027, the market for personalized hair care, which takes into account porosity among other factors, will reach $38 billion, with an annual growth of more than 25%.

Conclusions: porosity as a compass in the world of curl care

Understanding the porosity of curly hair is not just another beauty term, but fundamental knowledge that changes the approach to hair care.

“Instead of blindly following trends, determine the porosity of your hair and use this knowledge as a compass when choosing products and care techniques,” concludes Janine Cook, beauty editor at Harper’s Bazaar. “This will not only achieve better results but also save time and money on unsuitable products.”

Experts are unanimous: porosity is the factor that explains why the same products can give diametrically opposite results on different types of curly hair. And the deeper we delve into understanding this property, the closer we come to the ideal of personalized care, where each curly lock receives exactly what it needs.

In a world where individuality becomes the main value, understanding the unique properties of your hair is not a luxury, but a necessity. And porosity is the key to this understanding.