If you have low porosity hair and feel like it is stuck at the same length, I want to start with some good news that goes against most of the advice online: low porosity hair is usually the healthier, less damaged end of the spectrum, and it grows at the same rate as anyone else’s. The problem is rarely growth. It is retention, and it is buildup.
I worked through the science of this with my friend, a hair scientist and cosmetic formulator with a PhD in chemistry, because so much low porosity growth advice is built on a premise that does not hold up: the idea that your hair is desperate for moisture you have to force past a closed cuticle.
Low porosity hair grows at the scalp at a normal pace, roughly half an inch a month. It tends to repel water and hold onto product because its cuticle is intact and healthy, not because it is starving. So growing it is not about prying the cuticle open; it is about keeping a clean, light, well-handled head of hair so the length you grow does not break off or get weighed down. If you want the full care basics, those live in my complete low porosity hair guide; this post is about growth and keeping length.
Does Low Porosity Hair Grow Slower?
No. Hair growth happens at the follicle in your scalp, and that pace, around half an inch a month on average, is set by your biology, not by your porosity.[1] Low porosity describes how your hair interacts with water and product at the surface, not how fast it grows from the root. When low porosity hair seems stuck, it is almost always one of two things: product buildup making it look and feel the same week to week, or breakage at the ends quietly costing you the length you are gaining. If your hair is actually on the damaged, fast-absorbing end instead, see how to grow high porosity hair, since the approach there is different.
Low Porosity Usually Means Less Damage, Not Less Growth
Here is the reframe that changes everything. Low porosity hair repels water because its cuticle is lying flat and intact, which is generally a sign of healthy, undamaged hair.[2] Damage runs the other direction: bleach, color, heat, sun, and rough handling crack and lift the cuticle and push hair toward high porosity over time.[2,3] So if your hair is genuinely low porosity, you are usually starting from a strong position for retaining length, not a weak one. The goal is to keep it that way, rather than to treat it like it is broken and needs forcing open. For the full porosity picture and the testing myths, see my complete low porosity hair guide.
Growth Starts at the Scalp
Every strand you will grow starts at a follicle in your scalp, so a clean, healthy scalp is the foundation.[1] This matters a little more for low porosity hair, because it holds onto product, oil, and residue readily, and a coated scalp and hair shaft are exactly what makes low porosity hair feel heavy and look like it is not changing. A gentle, effective cleanse keeps things clear. You do not need a harsh weekly clarifying ritual or to strip your hair to open the cuticle; you just need a shampoo that actually cleans. See the best shampoos for low porosity hair for cleansers that clear buildup without leaving hair coated.
The Real Low Porosity Issue: Product Buildup
If there is one thing that quietly stalls low porosity hair, it is buildup. Because the cuticle is flat and tight, heavy creams, butters, and oils tend to sit on the surface rather than absorb, layer up over time, and leave hair greasy, limp, and dull. People read that as dryness and add even more product, which makes it worse. The fix is not to force product in; it is to use lighter products and to cleanse well enough that nothing accumulates.
A few practical moves: reach for lighter leave-ins and stylers over heavy butters, use oils that actually penetrate the strand rather than ones that only coat, and know what tends to weigh low porosity hair down so you can lighten up where it helps. This is about product weight and cleansing, not ingredient fear; you do not need to be scared of silicones or a gentle sulfate, you just need to cleanse well enough to keep things from piling up.
Growth Actives: What the Evidence Actually Supports
The supplement and oil aisle is full of growth promises, and very little holds up. Minoxidil is the only topical scientifically proven to regrow hair and slow hair loss. It is applied to the scalp, takes a few months of consistent use, and is worth a conversation with a dermatologist before you start.
Rosemary oil deserves a direct correction, because it gets recommended constantly. There is no solid evidence that rosemary oil grows hair. The popular claim that it rivals minoxidil rests on a single flawed human trial, and the only other study on it was done in mice, not people. I broke down exactly what those studies do and don’t show in Rosemary Oil for Hair Growth: Truth or Hype. The same goes for essential oils like eucalyptus, tea tree, and peppermint, and the DIY scalp blends marketed for growth: pleasant to use, but not proven to grow hair. Put your energy into scalp health and length retention instead.
Feed Hair Growth From the Inside
Hair is built from what your body has to work with, so a balanced diet with enough protein, iron, zinc, and vitamins supports a normal growth cycle. If you suspect a deficiency, the most useful step is bloodwork and a conversation with your doctor or a dietitian, since correcting a real deficiency can genuinely help while loading up on supplements you do not need usually does not. Biotin is the classic example: it only helps if you are actually deficient, which is uncommon, so do not count on a biotin pill alone to grow your hair.
Protect Your Length (Where Growth Is Won or Lost)
Because growth is rarely the bottleneck, the length you keep comes down to how gently you treat the hair you already have. The bonus for low porosity hair is that protecting it also keeps it low porosity, since new damage is what pushes hair toward high porosity in the first place.
- Detangle gently on conditioner-coated hair with a wide-tooth comb or your fingers, and handle wet hair carefully, since all hair is weakest when wet.
- Dust or trim damaged ends every ten to twelve weeks so small splits do not travel up the strand and cost you length.
- Use protective and low-manipulation styles, kept loose so they do not pull at the hairline.
- Switch to satin or silk pillowcases, bonnets, and scarves, and smooth hair ties, to cut the friction that snaps strands.
- Limit heat, and when you do use it, use an actual heat protectant and the lowest temperature that works; do not rely on oil or butter as a heat shield. Repeated high heat cracks the cuticle and is one of the fastest ways to turn healthy low porosity hair into damaged, high porosity hair.[3]
- If you diffuse, do it on lower heat; here are diffuser-friendly dryers worth considering.
Your Wash-Day Routine Still Matters
A light, consistent routine keeps low porosity hair clean, defined, and breakage-free between styles. The short version: cleanse well so nothing builds up, condition for slip, deep condition when hair feels rough, and keep your leave-ins and stylers on the lighter side. I cover the full routine and the ingredients to look for in the complete low porosity hair guide, with deeper dives on conditioners, deep conditioners, leave-ins, curl creams, gels, and pre-poo. If you want help keeping the hair conditioned day to day, my low porosity conditioning guide goes deeper.
Managing New Growth
As your hair grows, treat the new length the way you would protect anything healthy: keep the scalp clean, keep products light, keep your handling gentle, and be patient. New growth is the most undamaged hair you have, and the whole goal is simply to not wear it down. Consistency over months is what shows up in the mirror, not any single product or treatment.
Frequently Asked Questions
Does low porosity hair grow slower than other hair?
No. Growth happens at the follicle and runs at about the same pace regardless of porosity, roughly half an inch a month. Low porosity hair only seems to grow slowly when buildup makes it look the same week to week, or when the ends break off as fast as length is gained.
Can low porosity hair grow long?
Yes, and it is often well positioned to. Low porosity usually means a healthy, undamaged cuticle, so with gentle handling and light, clean styling, retaining length is very achievable. The trick is not weighing it down and not letting new damage creep in.
Why does my low porosity hair feel like it is not growing?
Most often it is buildup, heavy products sitting on top and leaving hair limp and unchanged, or breakage at the ends. Neither is a growth problem at the root; both are about what is happening on the strand.
Do I need to steam or clarify to grow low porosity hair?
You need to cleanse well enough to keep buildup from accumulating. You do not need to steam or harshly clarify to pry the cuticle open and force water in; a flat, intact cuticle is a sign of healthy hair, not a problem to fix.
Does rosemary oil help low porosity hair grow?
There is no solid evidence that rosemary oil grows hair, and the same goes for other essential oils marketed for growth. Full breakdown: Rosemary Oil for Hair Growth: Truth or Hype. Minoxidil is the only topical actually proven to regrow hair, so talk to a dermatologist if hair loss is your concern.
Is protein bad for low porosity hair?
Not inherently. The real issue for low porosity hair is product weight and buildup, not a protein-versus-moisture rule. Use what leaves your hair feeling good and clean, and judge by how it responds over a few wash days.
References
- Harkey MR. Anatomy and physiology of hair. Forensic Sci Int. 1993;63(1–3):9–18.
- 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.
- Gamez-Garcia M. The cracking of human hair cuticles by cyclical thermal stresses. J Soc Cosmet Chem. 1998;49(3):141–53.
