How often should we microneedle for hair regrowth. Once every two weeks? Once per week? Once per day? More? Hair loss forums continue to debate this very question.
Yes, evidence confirms that microneedling once every 1-3 weeks helps to regrow hair. At the same time, these intervals are also the only microneedling frequencies tested (so far) in humans with androgenic alopecia (AGA). Moreover, many men online are reporting incredible results (with photos) with daily microneedling – even with longer needles.
This begs the question: do more microneedling sessions evoke better results? And if so, how often should we microneedle to maximize our hair regrowth?
This Quick Win uncovers the evidence, and the answers.
The short answer: microneedling frequency depends on a number of factors: needle depth, applied pressure, and individual variances in wound-healing intervals (to name only a few). There are no concrete answers (yet) as to how often we should microneedle. And at the upper ends, we also need to balance out wounding frequencies with any potential increased risks of cancer.
Read on for the studies, photos, and more.
What is microneedling and how does it work?
Microneedlers (also known as dermarollers) are devices with tiny needles that are pressed or rolled onto the skin. These needles create “micro-injuries”. And, when repeated often, these micro-injuries accomplish a few things:
- A reorganization of collagen. Scar tissue (fibrosis) is disorganized collagen deposits underneath the skin. By creating these microinjuries, microneedling devices help to destroy disorganized collagen and lay down new, more organized collagen. (1) And, no, microneedling doesn’t actually penetrate deep enough to form new scar tissue (so long as you’re using the right needle length).
- An increase in growth factor provision. Microneedling stimulates the production of growth factors like platelet-derived growth factor and fibroblast growth factor (1), both of which are involved in the regulating the hair growth cycle. (2)
- Improves topical absorption. By creating micro-tears in the epidermal layer of the skin, topicals can more easily penetrate to the dermal and subcutaneous layers (where the hair follicle bulge rests). Theoretically, this should allow for these topicals to have a greater effect.
Encouragingly, these theories and purported mechanisms do translate to hair regrowth in those with pattern hair loss, or androgenic alopecia (AGA) – at least in the clinical studies published so far.
Here are a summary of the results: the needle lengths used, how often the microneedling devices were used, the hair count increases, andmore.
Microneedling for androgenic alopecia (AGA): summary of clinical trials
|Needle Length||Frequency||Combination?||Hair count increases cm²||
|Study 1: Bao et al. (3)||1.5mm-2.5mm||2 weeks||Yes, 5% minoxidil||23.4 alone; 38.3 with minoxidil||Infection, enlargement of lymph nodes (in elderly and immune-compromised), moderate pain, eczema|
|Study 2: Dhurat et al. (4)||1.5mm||1 week||Yes, 5% minoxidil||91.4||No significant adverse effects|
|Study 3: Dhurat et al. (6)||1.5mm||1 week for first 4 sessions; biweekly for the 11 thereafter||Yes, 5% minoxidil + 1mg finasteride||No hair count; 26-75% improvement after 6 months and 50-75% patient satisfaction||Not reported|
|Study 4: Abhijeet et al. (7)||1.5mm||3 weeks||Yes, 5% minoxidil and PRP||No hair count; microneedling + PRP + 5% minoxidil had better hair changes than 5% minoxidil lotion alone or 5% minoxidil + PRP||Not reported|
A quick glance at these results suggests two things:
- Microneedling enhances minoxidil’s effectiveness. Two studies now show that microneedling can double or triple the efficacy of minoxidil, and that combining these treatments lead to better outcomes than just doing microneedling alone, or minoxidil alone.
- Microneedling once weekly might be better than biweekly. Bao et al. (3) showed that microneedling once every two weeks resulted in a 25% increase in hair count. Dhurat et al. (4) showed that microneedling once per week resulted in a 40% increase in hair count. Both studies used a 1.5mm needle length; both studies used 5% minoxidil twice-daily alongside microneedling.
Of course, we can’t fairly compare percentage hair changes across two different studies: there are too many factors at play that could influence results (different subject demographics, study durations, investigators, etc.). But if we take this back-of-the-envelope comparison at face-value, we’re faced with an interesting takeaway…
More frequent microneedling leads to better results… at least when combined with minoxidil.
In fact, this takeaway is what has inspired so many Reddit users, HairLossTalk forum contributors, and others to begin testing more frequent microneedling sessions: twice per week, once per day, and more… all in hopes of maximizing their degree of hair regrowth.
So, how are their results stacking up?
First, we’ll uncover select before-after photos featured on these forums. Then, we’ll discuss long-term concerns with microneedling daily (namely, a potential increased risk of cancer).
Online anecdotes: microneedling frequencies & results
Microneedling once every 1-2 weeks
This Reddit user utilized a 2.0mm dermapen weekly alongside 5% minoxidil for his first 2 months. After 2 months, he moved to 10-14 day wounding intervals. He does not use minoxidil on the days that he microneedles.
Here are his (impressive) results.
This individual also used a 2mm dermapen once weekly in conjunction with a long list of topicals (you can view them here). He also saw marked hair regrowth.
This user employed weekly microneedling with a 1.5mm dermaroller alongside minoxidil (percentage not specificed). After 1.5 months, he transitioned to microneedling only with these results after 3 months (Note: left photo is +3 months; right photo is +0 months).
Microneedling twice daily
Some users also document great results with more frequent wounding intervals and shorter needle lengths.
For reference, this individual used a 1.0mm dermaroller twice daily with minoxidil for two years. He now uses finasteride but notes that he had great results even prior to finasteride.
These anecdotes suggest that weekly intervals, even with longer needle lengths of 2.0mm, are still effective in conjunction with minoxidil. It also suggests that needling using a 1.0mm needle length daily may also be effective.
But if these anecdotes are true – and more frequent needling is better for hair regrowth – do these better results come at a cost?
There are concerns over safety with microneedling. Namely, these concerns revolve around healing windows required for longer needle sizes used more frequently – and how this might increase our risks of cancer.
Microneedling frequencies: what you need to consider
There are two issues that may arise from more frequent microneedling sessions or deeper needle penetration (that of which is determined by needle length and the amount of pressure used during any given session): scarring, and an increased risk of cancer.
Wound healing windows depend entirely on the nature of an injury. This is true even with microneedling – as the pressure applied, the number of needles used, the duration of the procedure, and the needle depth penetration all influence the time needed to heal from a session.
The goal: to wound deep enough / often enough to evoke hair follicle proliferation – but not deep enough / often enough to cause scarring.
So, what does the evidence say about average healing times for wounds this deep? Specifically, wounds incurred by medical grade needles at depths of 0.25mm to 2.0mm (the same ones people experiment with for hair loss).
The short-answer: we don’t yet know. This is because following microneedling in human skin, we’ve yet to really thoroughly study the three stages of wound-healing (aside from clotting): inflammation, proliferation, and maturation.
Even still, we can summarize what the research says so far in respect to each of these stages.
Stage 1: inflammation
When it comes to needle lengths to avoid scarring, Dunkin et al. (5) found that skin cuts to depths of 0.5–0.6 mm may show signs of inflammation for 24-48 hours following the injury; however, these wounds will close without any trace of scar tissue.
To quote from the study:
“The visible inflammation phase (erythema) lasts on average about 48 hours. The redness on Caucasian skin decreases by 50% 4–6 hours after the treatment. Chilled silk layers (Cool Mask) soaked in hyaluronic acid are extremely helpful in reducing erythema by at least 50% in 30 minutes. Visible edema is unusual after microneedling. There may be a general slight swelling that fades within 48 hours. In chronic wounds progression toward healing often stalls in the inflammatory phase. At the wound edge, when re-epithelialization is arrested, microneedling of periwound skin may serve to induce a mild inflammatory response which may stimulate epithelial migration to occur. In addition, as previously mentioned the microneedling may help to restore the TEPs and electrotaxis of epithelial skin cells.”
Other researchers have also argued that wounding with longer needle lengths – 1.5mm to 2.00mm – also shouldn’t lead to scarring… provided that the needles are medical grade and used less frequently (i.e., once every 1-2 weeks).
This is why many people feel comfortable using a 0.5mm needling device each day, and why most clinical trials on microneedling have used 1.5mm to 2.0mm rollers with less frequencies (every 1-2 weeks).
Stage 2: proliferation
After the initial inflammatory response, the next stage of wound-healing is proliferation. This is when the wound is rebuilt with new tissues – extracellular matrix, collagen, etc. – that then build the foundation for new blood vessles (i.e., angiogenesis).
The proliferation phase starts immediately after microneedling and may reach its peak after 2 months. At present it is not known how epidermal and dermal stem cells are affected by microneedling.
Stage 3: remodeling (maturation)
New type III collagen fibers integrate into the existing skin matrix without any trace of fibrotic tissue. An interesting fact is that the new collagen formation is deposited from a depth of 0.6 mm upwards and towards the basal membrane, in most cases when needles with a length of 1.5 mm are used. (8)
Wounds heal within 4-6 weeks. But, the wounding initiated by microneedling is a (for the most part) controlled micro-injury. As such, these wounds take significantly less time to heal.
That said, it’s hard to specify a general healing window for a given microneedling session. This is because there are many factors that can play into the degree of microwounding and, thereby, the necessary window for a full recovery.
These factors are centered around the depth of penetration of the needle and individual variances in healing time. Essentially, the deeper the needle and the more pressure used during a microneedling session, the more healing time required – all of which is further influenced by how long your body will take to heal the treated area.
The bottom line: even small wounds can take weeks (or longer) for skin remodeling completion. This makes it tough to evaluate if microneedling more often is truly beneficial
In any case, here’s what is important: we need to allow our scalp to fully recover in between sessions. Otherwise, we may face a potential increased risk of unwanted side effects – like too much inflammation or scarring – both of which will likely impede hair regrowth in the long-run.
Beyond that, there’s one other major concern about microneedling from hair loss forums: a risk of cancer.
Chronic skin wounding may also pose an additional risk: cancer. However, this concern has been taken a bit of out context from most microneedling skeptics. Here’s why.
There are at least two studies demonstrating that chronic wounding may increase the risk of cancer. In the first study, investigators found that wounding enhanced the proliferation of a certain skin cancer cell – basal cell carcinomas – and thereby increased tumor growth (9). In the second study, researchers found that basal cell tumors actually originated from hair follicle stem cells and that chronic wounding enhanced hair follicle stem cell activity, and thereby basal cell carcinomas recruitment (10).
Obviously, these findings are cause for concern. After all, activating hair follicle stem cells is one of the potential mechanisms by which microneedling helps to regrow hair. If we’re inadvertently also causing cancer, that sort of defeats the purpose of our efforts.
At the same time, we have to balance out these findings with the facts. For starters, these studies weren’t on humans, they were on mice. And perhaps most importantly, these studies weren’t meant to represent a microneedling environment; they were meant to represent chronic inflammation from chronic disease (i.e., a persistent fungal infection, lupus, etc.).
Moreover, many researchers have even theorized that microneedling, paradoxically, can help reduce chronic inflammation by providing an avenue by which chronic wounds can bypass the very step-processes by which they get stuck during healing (5).
So, it’s actually unclear whether microneedling would actually increase or decrease the risk of cancer formation in chronically inflamed skin tissues. You can make arguments for either scenario.
In any case, my personal position is that it’s probably best to play it safe and allow for full recovery between microneeding sessions – even if maturation and remodeling hasn’t yet completed.
That means that straying away from wounding intervals used in clinical research may not necessarily come without increased risk. But, there’s just no way to quantify this risk as of yet.
Yes, some people are seeing great results with microneedling intervals shorter than 7 days. Yes, some people are using needles longer than 1.5mm weekly and still seeing improvements.
But, until more clinical evidence proves that these frequencies are safe, we can’t yet say if these practices are viable long-term. As such, our best bet is to stick to what’s researched: 1.5mm, 192-count microneedling devices performed at 1-3 week intervals.
Rob English is a researcher, medical editor, and the founder of perfecthairhealth.com. He acts as a peer reviewer for scholarly journals and has published two peer-reviewed papers on androgenic alopecia. He writes regularly about the science behind hair loss (and hair growth). Feel free to browse his long-form articles and publications throughout this site.