HAIR GROWTH / THE SCIENCE
Rosemary oil, scalp massages, biotin gummies—there is no shortage of things promising longer hair. But what can actually help your hair grow, and what is really just helping you hold on to the length you already have?
Search “how to grow hair faster” and you’ll find enough advice to turn your wash day into a part-time job. Oil your scalp. Massage it every night. Take a supplement. Try rice water. Buy the serum everyone suddenly has in their bathroom.
The less exciting truth is that hair growth starts inside the follicle, and a lot of how quickly and how long your hair grows is determined by biology.
That doesn’t mean your routine doesn’t matter. It just matters in a slightly different way than TikTok would have you believe.
First, how fast does hair actually grow?
Scalp hair grows about one centimetre per month on average, although the exact rate varies from person to person.
It also doesn’t grow continuously forever. Every follicle moves through a cycle: anagen is the active growing phase, catagen is a short transition phase, and telogen is a resting phase before the hair eventually sheds and the cycle begins again.
Genetics, age, hormones and your overall health can all influence that cycle.
So, no, your hair is not waiting for you to discover the right oil before it finally decides to grow.
Can you actually make your hair grow faster?
There isn’t a proven beauty hack that suddenly makes healthy follicles start producing inches of extra hair every month.
What you can do is make sure your body has what it needs to support normal hair growth. Nutritional deficiencies—including too little iron, protein, zinc or biotin—can contribute to hair loss in some people. Correcting an actual deficiency may help the hair recover.
The key words there are actual deficiency.
ABOUT THOSE HAIR GUMMIES…Biotin is everywhere in hair supplements, but research has found very little evidence that taking extra biotin improves hair growth in otherwise healthy people who aren’t deficient.
High-dose biotin can also interfere with certain blood-test results.
So if you think you’re deficient, testing makes more sense than guessing.
Then why does my hair feel like it never gets longer?
This is where things get more interesting—especially with curly hair.
Growing hair and seeing length are not exactly the same thing.
Your follicles can be happily producing new hair while the older ends are breaking off. Add curl shrinkage into the equation and you may be growing more hair than you realize.
This is what people mean when they talk about length retention: keeping enough of the hair you grow that you can actually see the difference over time.
IF LONGER HAIR IS YOUR GOALBe gentler when you detangle. Use enough conditioner or slip and work through knots instead of pulling through them.
Watch repeated tension. Tight ponytails, braids and other styles that constantly pull on the same areas can damage hair and, over time, the follicle.
Use heat thoughtfully. Heat styling doesn’t have to be forbidden, but repeatedly damaging already-fragile lengths makes retention harder.
Keep the hair conditioned. Conditioner helps reduce friction and makes hair easier to manage, which matters when breakage is what is stealing your length.
Do hair oils help with growth?
Some oils absolutely have benefits for hair. The question is which benefit.
Coconut oil has particularly good evidence behind it as a hair-care oil. Research has found that it can penetrate the hair fibre and reduce protein loss, which may help protect the strand from damage.
That can be very helpful for someone trying to retain length.
It is not the same thing as proving that coconut oil makes the follicle grow hair faster.
Something can be great for your hair without being a hair-growth treatment.
Okay, what about rosemary oil?
This one is a little more interesting than many viral hair-growth ingredients.
A small randomized study followed 100 people with androgenetic alopecia for six months and compared rosemary oil with 2% minoxidil. Both groups had increased hair counts by six months, with no significant difference in hair count between the groups.
Promising? Yes.
Proof that rosemary oil will make everyone’s hair grow faster? Not quite. It was one relatively small study involving people with a specific type of hair loss, so there is still plenty we don’t know.
And what actually works for hair loss?
This is where the conversation changes from hair care to treatment.
If someone has a diagnosed form of hair loss, there are evidence-based options. Minoxidil, for example, can stimulate growth and help prevent further loss in certain conditions.
But different kinds of hair loss need different treatment. A widening part is not necessarily the same problem as a sudden handful of shedding, a bald patch or breakage around the hairline.
WHEN TO GET IT CHECKEDConsider seeing a doctor or dermatologist if you notice sudden or significant thinning, a widening part, bald patches, a receding hairline or shedding that is noticeably different from your normal.
Finding the cause is much more useful than throwing six “growth” products at it.
The bottom line
Your hair is probably already growing.
If your goal is more visible length, the biggest difference may come from protecting that growth once it leaves your scalp: less breakage, less unnecessary tension and a routine that keeps the hair manageable.
If your growth or shedding has genuinely changed, look for the reason. And if you love your scalp massage or your Sunday oiling ritual? Keep it.
Just don’t make one bottle responsible for your entire follicle biology.