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An interesting, really potentially confusing distinction keeps popping up in some of the subreddits regarding the difference between a .25 mm dermaroller and a .5 mm or other medical-grade dermaroller length.
Lots of brands are selling dermarollers with .25mm needles. They are great for what they’re intended for! If you want to increase serum penetration or if you have an active ingredient OTHER THAN AN ACID that you want to see penetrate further, .25 is a great choice. (I still wouldn’t recommend buying that $200 one–you know the one I mean.)
To be fair, acids have no business anywhere near dermarollers of any length.
So, what can .25 mm dermarollers do? .25 dermarollers are an excellent option for younger people with no signs of aging who want to avoid getting any, or people with hormonal acne but no other skin problems, or people whose primary skin goals include brightening, mild improvements in texture, or preventing the effects of aging before they appear.
Basically, if your primary skin goals can be accomplished with products, a .25mm dermaroller will help you achieve them.
.25 is also optimal for some paradoxical hyperpigmentation sufferers. Paradoxical hyperpigmentation is when your skin responds to a product intended to fade hyperpigmentation by getting stressed out and causing more or darker hyperpigmentation. .25 will work for some of these cases because it allows them to use a gentler depigmentation agent and still see results because it penetrates more deeply.
I suspect that you could also use them to microneedle for hair loss; research on dermarolling with minoxidil usually calls for .5 mm, but the goal is product penetration and .25 is usually adequate for that.
.25 dermarollers also don’t require the same kind of super-intense cleaning practices as longer needles. You still need to keep it clean, of course, just like your phone or your pillowcase or anything else that touches your face. But it isn’t breaking your skin or drawing blood or anything where you might get sick if you aren’t cleaning it enough. So, using it is less of a complicated process.
Here’s what .25 dermarollers don’t do: they do not do collagen induction. They won’t repair fine lines, they won’t remove acne scars or stretch marks, they won’t work for moderate to major textural improvement, or and they won’t make permanent improvements to your skin. Most of the major skin-restructuring strategies I’ve written about on this site can’t be accomplished with a .25mm dermaroller–the needles just aren’t long enough to cause the skin to turn over.
You might see major improvements while you’re using them with products, but once you discontinue the products and .25mm dermaroller, the results you’re seeing will fade too, unlike dermarolling with longer needles.
.25 mm dermarollers aren’t long enough to encourage the body to create new skin when you roll (see “How Do Dermarollers Work?” for more on this), and the process of creating new skin is the only way to permanently correct skin damage and aging problems. Even when you get an expensive laser treatment, it works the same way, by damaging the skin so that the body re-generates new. .5mm or longer needles just do so cheaply, and with more mild damage (so, slowly).