The Tale of the Tiny Needles: A 2023 Study That Shook the Hair Loss World
Let me share a story with you—a story that recently rippled through the community of those battling androgenetic alopecia. It begins with a tool you might know well: micro needling. For years, I have been a strong advocate for this technique, especially when paired with other treatments like 5-alpha reductase inhibitors, anti-androgens, and growth stimulants. The reason is simple and stems from how micro needling works. It doesn’t just sit on the surface; it dives deep, releasing growth factors through platelet activation and skin regeneration. It wakes up stem cells in the hair bulge area, enhances the expression of hair growth-related genes, and activates the Wnt and several other pathways. These mechanisms work synergistically to promote hair growth. What's more, micro needling acts like a key, unlocking the scalp to improve the absorption of topicals like minoxidil, topical finasteride, or topical dutasteride.
For years, the evidence seemed clear. One of the most well-known studies, a randomized blind study led by Dr. Dhurat, offered a powerful glimpse into its potential. In that study, participants were divided into groups. One group received weekly micro needling treatments using a 1.5 millimeter derma roller, combined with 5% minoxidil applied twice a day. The other group received only minoxidil. The results were striking. After 12 weeks, the mean change in hair count for the micro needling plus minoxidil group was nearly four times greater than the minoxidil-only group—something like 80 hairs compared to just 22. It was a story of synergy, where one plus one equaled much more than two. Thousands of anecdotal before-and-after photos on forums like Tressless seemed to echo this, with people sharing dramatic improvements in density after adding micro needling to their regimens.
But then, a new chapter arrived in January 2023. A Brazilian study titled "Efficacy and safety of scalp micro needling in male pattern hair loss" was published, and it threatened to rewrite the narrative. Some viewers sent it my way, asking for my thoughts. And so, I took a careful look. This study involved 30 patients in a randomized, single-blinded setup. They were divided into two groups: 15 used a 192-needle derma roller, and 15 used a motorized tattoo cartridge device. Both devices were set at 1.5 millimeters and applied vertically, horizontally, and obliquely until pinpoint bleeding was achieved. They underwent four monthly sessions of scalp micro needling. Measurements of scalp coverage and hair density were taken at baseline, then at 4 and 16 weeks after the last session. Scalp biopsies were also performed to check for scarring changes. The headline was provocative: micro needling did not result in any improvement in hair density or hair count. In fact, the study seemed to suggest it might even be detrimental for some.
Peeling Back the Layers: Why This Study Might Be Flawed
Now, before you toss your derma roller aside, let me walk you through the details, because the story here is more about the study’s design than a final verdict on micro needling itself. First, consider the frequency. Most successful studies micro needle once a week. This study did it once every four weeks. At a depth of 1.5 millimeters, that long gap may simply not be enough to stimulate consistent growth. Imagine watering a plant only once a month in a dry climate—it's unlikely to thrive. Second, the sample size was very small: only 30 patients to begin with. And the problem worsened with follow-ups. By the first visit, 3 participants in the roller group and 1 in the cartridge group had dropped out. By the second follow-up—16 weeks after the last session—another 4 from the roller group and 3 from the cartridge group failed to show. That left us with just 8 out of 15 in the roller group and 11 out of 15 in the cartridge group. Such a tiny sample size leads to high variability, reduces the power of the study, and increases the margin of error, making the results nearly meaningless for drawing broad conclusions.
There was also no control group, which is a significant oversight. How can we compare results without a baseline of people doing nothing? And consider the washout period. Participants were not allowed to use any drugs that stimulate hair growth during the study. Those on previous topical or hormonal treatments had a washout period of 6 months for topicals and 12 months for hormones. Even with that, 6 months may not be enough for someone to revert to their true baseline. They might still be shedding or losing hair because they stopped treatment, introducing inconsistencies into the data. The study itself acknowledged that the decrease in hair density was more pronounced in the roller group after 16 weeks. But let’s look at the actual numbers. At the first follow-up, only 4 out of 12 participants in the roller group and 2 out of 14 in the cartridge group showed any improvement in clinical photos. By the last follow-up, only 2 in the roller group and 1 in the cartridge group sustained that improvement. Neither group presented an improvement in total hair count. When analyzed as a whole, all patients showed a decrease in hair density after 4 and 16 weeks. The authors noted that most subjects were placed between a negative 2, negative 1, or zero—meaning they saw moderately decreased, slightly decreased, or no change in scalp coverage.
The Author’s Own Speculation and My Deeper Reflection
The authors themselves were uncertain why their results differed from other studies. They speculated that their participants might have been older, with longer disease duration and higher balding severity. They also acknowledged that other published studies involved younger participants with shorter disease duration and a greater number of sessions. This is a crucial point. The fact is, there are no set, established standard protocols for micro needling. Researchers have yet to find the perfect medium for frequency, needle depth, needle type, and pressure. It’s an area that still needs long-term study. We might even need to individualize protocols based on a person’s scalp thickness and the degree of hair loss.
My own reflection is this: I do not recommend micro needling as monotherapy. Why? Because it doesn’t target the root cause of androgenetic alopecia. To truly combat this condition, you need something that targets androgens or blocks them as the primary source of treatment. Minoxidil, micro needling, laser therapy, and other treatments are secondary. They are the tools you stack on top of 5-alpha reductase inhibitors or anti-androgens to maximize your chances of improvement. The best evidence for micro needling’s success comes from its use in conjunction with other treatments. Most people who incorporate it feel it has been a real difference maker, no matter what other topicals or drugs they are on. Perhaps the key is the synergy—each treatment working through a different mechanism of action, creating a whole greater than the sum of its parts.
A Final Word of Wisdom for Your Journey
So, my friend, if you have been micro needling religiously and seeing results, do not panic over this single study. It was, in my opinion, poorly designed: a small sample size, no control group, infrequent sessions, and an odd reassessment period four months after the last treatment. Patients who had previously been on hair loss treatments may not have had enough time to revert to their baseline, and shedding could have continued despite the washout. The story of micro needling is not yet fully written. There are more studies showing its benefits for promoting hair growth than not, and combined with the overwhelming anecdotal evidence, it’s difficult to believe it has no therapeutic impact.
If you continue to micro needle, I recommend sticking with a needle length of 1.5 millimeters at the maximum, based on the general consensus of most available studies. Aim for once a week at that depth, achieving erythema or pinpoint bleeding at most. And always remember that this is a powerful partner, not a lone hero. For those who have yet to start, consider building a foundation with treatments that target androgens first, then layer on micro needling to unlock their full potential. The journey of hair regrowth is a patient one, filled with both triumphs and cautious steps. But with wisdom, you can navigate the tales that science tells us, separating the noise from the signal.