The average person picks a shampoo based on their hair type: straight, curly, wavy, or coily. But that classification tells you nothing about how your hair actually absorbs moisture. I learned this the hard way after years of buying products labeled for curly hair that left my strands brittle and frizzy. A stylist finally explained that my hair was low porosity, meaning the cuticles lay flat and repelled water. Suddenly, everything made sense. Porosity, not curl pattern, determines which ingredients will sink in and which will sit on top.
Cuticle structure is the key variable. If your hair cuticles are tightly closed, water and oils slide right off. High-porosity hair, with lifted cuticles, absorbs everything quickly but also loses moisture fast. Most commercial products are formulated for medium porosity, which leaves low- and high-porosity heads frustrated. That is why specialty lines like Ricitos de Oro Nourish target specific porosity issues by using lightweight oils and humectants that penetrate rather than coat. The difference between a product that works and one that doesn’t often comes down to molecular size of the ingredients.
The float test is not reliable
Many blogs tell you to drop a clean strand of hair in a glass of water. If it floats, you have low porosity. If it sinks, high porosity. That test is junk science. Hair gets waterlogged over time, and clean hair behaves differently than styled hair. Instead, try a better method: spray a small section of dry hair with water. If the water beads and rolls off, you are low porosity. If it absorbs in under a minute, you are high or medium. But even that is just a rough guess. The most accurate way is to note how your hair behaves after washing: does it take hours to dry? Does conditioner sit on top leaving a greasy film? Those are real signs.
Low-porosity hair needs smaller molecules
Low-porosity hair resists penetration. Thick oils like coconut or shea butter just sit on the surface and build up, making hair look dull and limp. What works instead are smaller molecules such as argan oil, grapeseed oil, or hydrolyzed proteins. Aloe vera juice and glycerin also slip through tight cuticles because they are humectants that attract moisture without a heavy film. Heat helps, too. Applying a warm towel or using a steamer forces the cuticles to lift slightly, allowing conditioners to enter. But the product itself must be lightweight. If you see water and glycerin high on the ingredient list, you are on the right track.
High-porosity hair needs sealing, not just moisture
High-porosity hair has gaps and tears in the cuticle layer. It soaks up water fast but loses it just as quickly, leading to frizz and breakage. The fix is not more moisture; it is protein and sealing agents. Products with hydrolyzed keratin or wheat protein fill in those gaps temporarily, making the hair stronger. Then you need butters or silicones to lock the moisture in. The tricky part is avoiding too much protein, which can make hair stiff and snap. You want a balance: a protein treatment once a month, then regular use of emollients like shea butter or dimethicone. Pay attention to how hair feels after a protein conditioner. If it feels hard, you overdid it.
How to read ingredient lists for your porosity
Most people ignore the ingredient list beyond the first few items. For porosity-specific care, look past the water and surfactant. For low porosity, avoid ingredients with names ending in -one or -ate, which are heavy polymers. Seek out amodimethicone over dimethicone because it is lighter and rinses cleanly. For high porosity, look for amino acids and butters. Avoid alcohols like cetyl alcohol only if the product also contains drying SD alcohol. The middle of the list matters: if there is silk protein or panthenol, those are good for both types but the concentrations differ. Testing one product at a time is the only way to know for sure. Keep a simple log of what you used and how your hair looked the next day.
Myths about hair porosity and damage
Many people assume low porosity means healthy hair and high porosity means damaged hair. Not true. Textured hair often has low porosity naturally, and chemical processing changes porosity regardless of initial condition. You can have strong high-porosity hair from heat styling that you maintain well. You can also have brittle low-porosity hair from dehydration. The porosity is a characteristic, not a judgment. The goal is to match the product to the current state of your hair, not to try to change your porosity permanently. You cannot open low-porosity cuticles with vinegar or close high-porosity cuticles with cold water. Those are old wives’ tales. The only effective approach is product selection based on molecular weight and ingredient behavior. Once you start paying attention to how your hair reacts to different formulations, you stop blaming the hair and start blaming the bottle.