Fact Checked & Reviewed By Leonela Paladino
Leo has more than 17 years of valuable experience as a researcher and lecturer in the Biology and Genetics field. Holding a PhD in Biology…
For years, many of us in the curly hair community leaned on observation, trial, and shared experience to make sense of our hair. We learned to test our porosity by dropping a strand in a glass of water, sorted ourselves into low, medium, or high, and then chased the products that were supposed to match our type.
The frustration was real. What we often lacked was the language to describe what was actually happening on the surface of the hair fiber.
Over time, I started noticing that a lot of the porosity advice circulating online did not line up with what cosmetic chemistry actually shows about the cuticle, damage, and how water moves through hair. So I went to the source. I reached out to my friend, a hair scientist and cosmetic formulator with a PhD in chemistry, and asked her to walk me through it.
One thing became clear quickly: the community observations were valid, but the explanations were often simplified or pinned to the wrong cause. Porosity is not a fixed personality you are born with and keep for life. It is a reflection of the condition of your cuticle, and it shifts as your hair is damaged or protected. The popular float test does not measure it reliably. And many of the rituals we were told to build around our “porosity type,” from clarifying every week to apple cider vinegar rinses, do not hold up the way we thought.
The goal of this guide is not to dismiss what you have experienced. It is to look at what the research says about the cuticle, damage, and conditioning, so you can stop guessing at a label and start reading what your own hair is telling you.
What is Hair Porosity?
Hair porosity describes how easily water and product move into and out of a strand through the cuticle, the shingle-like outer layer of each hair. [1,2] All hair is permeable to water to some degree; what differs is how quickly that water moves in and out, which comes down to the condition of the cuticle. What we call “low” or “high” porosity simply reflects how tight and intact that cuticle is versus how lifted and gapped it has become. [2,4]
The most important shift in understanding is this: porosity is not a permanent hair type. It is a measure of cuticle condition, and for most people higher porosity is a sign of accumulated damage rather than something fixed at birth. [2,3] That is good news, because condition can be protected and managed even when damage cannot be undone.
Up close, a high porosity strand has a cuticle with lift, gaps, and fissures along its length. [1,2,3] Picture a pine cone: a healthy cuticle lies flat and smooth, while a high porosity cuticle is raised and uneven, so it catches, tangles, and loses water quickly. [4] That openness is also why the strand is structurally weaker and more prone to breakage under tension.
How To Tell What Porosity Your Hair Is
This is where I have changed my advice the most. For years I pointed people to the float test: pluck a clean strand, drop it in a glass of water, and see whether it sinks (high porosity) or floats (low porosity).
Here is what I have come to learn. The float test is not a reliable way to measure porosity. [2] Whether a strand sinks or floats has more to do with trapped air, surface oils, and leftover product than with the true condition of your cuticle. Real porosity is measured with lab instruments, not a drinking glass. So if your strand floated one week and sank the next, that is the test failing, not your hair changing overnight.
A far better read comes from watching how your hair behaves over time. You likely lean toward high porosity if you notice:
- It feels dry or rough to the touch, even soon after washing
- It soaks up product fast but does not stay soft for long
- It frizzes easily and is hard to settle
- It dries quickly after washing
- It tangles easily and snags on itself
- It looks dull rather than reflective
- It breaks more readily under tension
As Science-y Hair Blog has long pointed out, porosity is best understood through observation: how your hair feels, how it reflects light, and how it responds to products across several wash days. The honest answer to “what is my hair porosity” is rarely a single fixed label. It is a current condition you can learn to read, and the only test that truly counts is watching your own hair respond to one change at a time.
Types Of Porosity Hair: High vs Low vs Medium
Rather than three permanent categories, think of porosity as a range of cuticle condition, defined by the number and size of openings along the cuticle. [10] Here is how the levels compare:
| Porosity level | What it reflects | How it tends to behave |
| Low | A tight, intact, smooth cuticle layer. Often newer or less-processed hair. | Slow to take in water and product; can feel coated or resistant; slow to dry. |
| Medium / normal | A largely intact cuticle with some lift. The middle of the range, not a fixed personality. | Takes in and holds onto product fairly evenly; generally easy to work with. |
| High | A lifted, gapped, or damaged cuticle. Usually the result of accumulated damage. | Takes in water and product fast, loses it fast; prone to dryness, roughness, frizz, and breakage. |
If you want the other end of the spectrum, see my full guide to low porosity hair (and where low porosity protein actually fits in).
What Causes High Porosity Hair?
Because high porosity is mostly about damage, it helps to know what lifts and wears down the cuticle in the first place. The most common causes are:
Chemical treatments
Color, bleach, relaxers, and perms break down the hair’s natural structure and its internal bonds to do their job, which lifts and weakens the cuticle and raises porosity over time. [4,6]
Heat styling
Frequent flat ironing, curling, and high-heat blow drying can lift or fracture the cuticle, pushing porosity higher with repeated exposure. [5]
Environmental exposure
Sun, wind, and saltwater gradually degrade the cuticle and leave it more open and more fragile. [7]
Mechanical damage
Rough handling, aggressive brushing, tight styles, and friction from cotton towels and pillowcases physically wear the cuticle away, raising porosity. [6,8,9]
How To Care For High Porosity Hair (A Routine That Works)
Forget the old “hydrate, seal, and balance” mantra. You cannot add water to a hair strand and lock it in; the water content of hair is governed mostly by the humidity around it, not by a product. [NEW-A] What you can actually do is simpler and more honest: condition the surface and protect the strand from further damage.
This matters because high porosity hair is already structurally compromised, and that damage usually cannot be reversed; a fresh cut is sometimes the most effective reset. [11] Everything below is about making the hair you have feel smoother and stronger to handle, and slowing down further wear.
Condition well, and often
Regular conditioning and deep conditioning improve slip, softness, and elasticity, which makes high porosity hair easier to detangle and less likely to snap while you work with it. [12,13] One thing to be clear about: conditioning is a temporary surface benefit that washes out. It smooths and coats the cuticle for a while; it does not rebuild the inner cortex or permanently lower your porosity. [17]
Bond-building peptide treatments such as K18 are designed to reach the cortex and reconnect broken bonds, a different mechanism from surface conditioning, though independent evidence that they truly rebuild hair structure is still limited. [20]
The single most useful habit: watch how your hair responds to each product over a few wash days, changing one thing at a time. That trial on your own hair is the only test that actually tells you what works.
Use protein when damage calls for it
Hydrolyzed proteins and amino acids can temporarily adsorb to the surface of damaged hair, filling in roughness so the strand feels stronger and breaks less during a wash. [13] The effect is real but temporary and washes out; protein is not rebuilding your cortex, and there is no such thing as a fixed “protein-moisture balance” to chase. Use it when your hair feels weak or overly stretchy, skip it when your hair feels stiff, and let your own results guide the frequency.
Pre-poo to reduce swelling stress
Applying an oil before you wash can slow how much water rushes into a porous strand, which reduces the swelling and stress that comes with prolonged soaking. [14] Coconut oil is the most studied here and is also associated with reduced protein loss; grapeseed or olive oil are reasonable alternatives if coconut does not suit your hair. [19]Layer products to slow water loss
The LOC method (Liquid, Oil, Cream) and LCO method (Liquid, Cream, Oil) are just ways of layering a conditioning product and an oil so the surface stays smoother and loses water more slowly through the day. High porosity hair usually tolerates this layering well. Use whichever order leaves your hair feeling best.
Protect the strand from further damage
Because high porosity hair is already fragile, your biggest wins come from preventing new damage:
- Choose looser styles that do not pull at the hairline, and handle wet hair gently, since it breaks most easily under tension.
- Air dry when you can; if you blow dry, use a warm-to-cool setting to limit heat damage. [5,18]
- Limit long sun exposure, and swap cotton towels and pillowcases for smoother fabrics that create less friction. [7]
A note on pH rinses and apple cider vinegar
I used to be a believer in apple cider vinegar rinses. I told readers that a diluted ACV rinse would “flatten the cuticle,” balance pH, and lock in moisture, and I was sure I could feel the difference.
Here is what I have come to learn. The evidence for ACV specifically doing any of that is very weak. Hair pH does matter, and keeping your products in a mildly acidic range can support a smoother cuticle and more shine. [17] But that benefit comes from well-formulated, pH-appropriate products, not from vinegar in particular.
A homemade ACV rinse is unpredictable in strength, easy to over-concentrate, and is not a reliable substitute for a product designed to do the job. If you enjoy it and your hair likes it, it is unlikely to hurt at a high dilution; just know it is not the cuticle-sealing fix it gets credited as.
The Truth About Clarifying Shampoos
The curly community treats clarifying shampoo almost like a monthly cleanse ritual, and I understand why. When buildup leaves your hair limp, dull, or unresponsive, a hard reset feels like the answer. So let me be careful here, because the truth is more freeing than the ritual.
A shampoo that actually cleans already removes buildup. For most people, a regular shampoo used properly clears away the sebum, oils, and styling product that accumulate on the hair. Buildup is not a silicone-only problem; it is formula-dependent, and natural oils and your own scalp sebum contribute to it just as much. Whatever the source, it washes out with ordinary cleansing.
So why does clarifying feel so dramatic? Part of it is the contrast. A strong cleanse strips the surface, and then the conditioning agents that follow make the hair feel newly soft. That soft, “reset” feeling is the conditioning step doing its work, not a special clarifying magic that a normal wash lacks.
Where a true clarifying step does earn its place: right before a bond-repair treatment such as K18, where you want a genuinely clean surface so the treatment can reach the hair. Outside of that, if your everyday shampoo cleans well, a separate weekly clarifying habit is usually unnecessary, and on fragile high porosity hair, over-clarifying just adds wear. Reach for it when your hair genuinely feels coated and unresponsive, not on a calendar.
Best Oils for High Porosity Hair
High porosity hair tends to do well with heavier oils that smooth the surface and slow water loss. [15,16]
Worth trying: castor, coconut, avocado, and olive oils, plus shea and mango butters.
Use with a lighter touch: very thin, fast-absorbing oils used on their own, since they leave only a light film and slow water loss less than richer oils and butters; and heavy butters used without thorough cleansing, since they can build up. (Coconut oil is the exception to the light-equals-weak idea: it is light but penetrates the strand, which is why it sits in the list above.)
Best Products For High Porosity Hair
The right products are the ones that smooth and condition the surface, support gentle detangling, and limit further damage. Categories below; keep your existing product blocks in place on the live post.
Shampoos
If you want more shampoo recommendations along with a clear breakdown of which ingredients to look for and avoid, this guide will walk you through it: The Best Shampoos for High Porosity Hair and Key Ingredients.
Use 'muse' at checkout for a discount.
When You Actually Need a Clarifying Shampoo
See the section above. Reach for one when hair feels truly coated, or before a K18 treatment, not on a fixed schedule.
Clarifying Shampoos
Co-Wash
Conditioners
For a deeper look at conditioners and the ingredients that support high porosity hair, refer to: Rinse-Out Conditioners for High Porosity Hair: Key Ingredients.
Leave-in Conditioners
Here are more high porosity leave-in conditioners with information about the key ingredients you should look for: High Porosity Hair: Best Leave-In Conditioners and Key Ingredients
Curl Creams
Not sure which curl creams to choose? This guide breaks down the ingredients that work best for high porosity hair: The Essential Ingredients You Need to Consider in Curl Creams for High Porosity Hair.
Foams / Mousses
Gels
For more gel options for high porosity hair and a breakdown of ingredients to include and avoid, see this guide: Best Gels for High Porosity Hair: Key Ingredients.
Use 'muse' at Bounce Curl's checkout for a discount.
Deep Conditioners
In my own routine, a rich masque left on for about 15 minutes has made the biggest difference in how manageable my hair feels; over time I noticed less breakage.
Quick myth to clear up while we are here: we have all heard that rinsing with cold water seals the cuticle and locks in shine. It does not. Water does not seal the cuticle; if anything, it swells the strand. [1]
What actually flattens and smooths a raised cuticle is the conditioner or masque itself, which is why your hair feels softer after this step no matter how warm or cool your final rinse is. A little goes a long way, so I work it from roots to ends with a wide-tooth comb.
If you want more deep conditioner options along with a breakdown of the ingredients that work best (and what to avoid), see this guide: Deep Conditioners for High Porosity Hair: Key Ingredients.
Oils
For a deeper look at oils and the ingredients that support high porosity hair, refer to: Discover the Most Beneficial Oils for High Porosity Hair.
Protein Treatments
Not sure which protein treatments to use? This guide explains the best types of proteins for high porosity hair: Protein Treatments for High Porosity Hair (Learn the Best Type of Proteins to Use).
If you need a good dandruff shampoo, check out my blog, ‘The Best Dandruff Shampoo for Curly Hair: Find the Right Solution for You.’
Frequently Asked Questions
Is high porosity hair good or bad?
Neither. High porosity simply means your cuticle is more lifted and worn, usually from damage. It calls for a care approach focused on conditioning the surface and protecting the strand, rather than a verdict on your hair. Many people with high porosity hair have gorgeous, healthy-looking results once they stop chasing a label and start handling their hair gently and consistently.
Does high porosity hair dry quickly?
Yes. Because the cuticle is lifted and open, water moves out of the strand quickly, so high porosity hair often air dries faster than lower porosity hair. That same openness is why it can feel dry soon after washing, and why slowing water loss with conditioning and a light oil layer can make the hair feel smoother for longer.
How often should I wash high porosity hair?
It depends on your scalp, your activity level, and the products you use. There is no universal number. Most people do well spacing wash days enough to avoid stripping the hair while still removing buildup. Watch how your hair and scalp feel and adjust; if your hair feels coated and limp, you may be due to cleanse, and if it feels dry and brittle, you may be washing too often.
Can high porosity hair become low porosity?
Not in the sense of permanently changing your hair type, because the existing damage to the cuticle cannot be undone. What you can do is improve the condition and manageability of the hair you have, and prevent new damage so fresh growth comes in healthier. Over time, that is what makes high porosity hair behave better, even though the underlying porosity of damaged lengths stays high.
Is high porosity hair sensitive to protein?
It varies from person to person, and the only way to know is to try it on your own hair. Some high porosity hair feels stronger and less breakage-prone after a protein treatment, while other hair feels stiff or straw-like. Introduce protein on its own, change nothing else, and judge by how your hair feels over the next few wash days. Let that result, not a rule about balance, guide how often you use it.
References
- Barba C, Martí M, Manich AM, Carilla J, Parra JL, Coderch L. Water absorption/desorption of human hair and nails. Thermochim Acta. 2010;503–504(1):33–9.
- Hessefort YZ, Holland BT, Cloud RW. True porosity measurement of hair: A new way to study hair damage mechanisms. J Cosmet Sci. 2008;59(4):303–15.
- Robinson V. A study of damaged hair. J Soc Cosmet Chem. 1976;27:155–61.
- Velasco MVR, Dias TC de S, Freitas AZ de, et al. Hair fiber characteristics and methods to evaluate hair physical and mechanical properties. Brazilian J Pharm Sci. 2009;45(1):153–62.
- Velasco MVR, Dias TC de S, Freitas AZ de, et al. Hair fiber characteristics and methods to evaluate hair physical and mechanical properties. Brazilian J Pharm Sci. 2009;45(1):153–62.
- Horev L. Environmental and cosmetic factors in hair loss and destruction. In: Tur E, editor. Environmental Factors in Skin Diseases. S. Karger AG; 2007. p. 103–17.
- Robbins CR. Chemical and Physical Behavior of Human Hair. 4th ed. New York, NY: Springer; 2002. 483 p.
- Kelly SE, Robinson VNE. The effect of grooming on the hair cuticle. J Soc Cosmet Chem. 1982;33:203–15.
- Robbins C, Kamath Y. Hair breakage during combing. III. The effects of bleaching and conditioning on short and long segment breakage by wet and dry combing of tresses. J Cosmet Sci. 2007;58(4):477–484.
- Dubief C, Mellul M, Loussouarn G, Saint-Léger D. Hair Care Products. In: Bouillon C, Wilkinson J, editors. The Science of Hair Care. 2nd ed. CRC Press; 2005. p. 141–82.
- Bosley RE, Daveluy S. A primer to natural hair care practices in black patients. Cutis. 2015;95(2):78–80,106.
- Trüeb RM. Aging of hair. J Cosmet Dermatol. 2005;4:60–72.
- Aguh C. Developing a Healthy Hair Regimen I: Formulating an Optimal Cleansing and Conditioning Regimen. In: Aguh C, Okoye GA, editors. Fundamentals of Ethnic Hair. Cham: Springer; 2017. p. 79–89.
- Keis K, Huemmer CL, Kamath YK. Effect of oil films on moisture vapor absorption on human hair. J Cosmet Sci. 2007;58(2):135–45.
- Barve K, Dighe A. Hair Conditioner. In: The Chemistry and Applications of Sustainable Natural Hair Products. Cham: Springer; 2016. p. 37–44.
- Demir E, Acaralı N. Comparison on Quality Performance of Human Hair Types with Herbal Oils (Grape Seed/Safflower Seed/Rosehip) by Analysis Techniques. ACS Omega. 2023;8(9):8293–302.
- Gavazzoni Dias MFR, de Almeida AM, Cecato PMR, Adriano AR, Pichler J. The Shampoo pH can Affect the Hair: Myth or Reality? Int J Trichology. 2014;6(3):95–9.
- Lee Y, Kim Y-D, Hyun H-J, Pi L, Jin X, Lee W-S. Hair shaft damage from heat and drying time of hair dryer. Ann Dermatol. 2011;23(4):455–62.
- Rele AS, Mohile RB. Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage. J Cosmet Sci. 2003;54(2):175–192.
- Martins E, Castro P, Ribeiro AB, Pereira CF, Casanova F, Vilarinho R, Moreira J, Ramos ÓL. Bleached Hair as Standard Template to Insight the Performance of Commercial Hair Repair Products. Cosmetics. 2024;11(5):150.
