How Bad Is It Really to Shave With an Old Razor?

Quick survey: When was the last time you replaced your razor? Last week, last month, last year (gulp)?

We get it: We can all become a little lazy about buying new blades. But shaving with an old, dull or rusty razor can be a real problem for your skin.

Here, we spoke with board-certified dermatologist Lauren Ploch, MD, MEd, to learn how shaving with a not-so-fresh razor can sabotage your skin health (and how often to banish battered blades for shiny new ones to avoid any issues).

Always get an itchy, tender red rash after shaving? You might want to think about the last time you replaced your razor.

Otherwise known as razor burn, this skin irritation is frequently caused by shaving with a blunt blade.

"As a blade dulls, it does not cut uniformly along the length of the blade," Dr. Ploch says. "This results in an uneven shave that can lead to razor burn."

Like razor burn, ingrown hairs (those that curl down and grow back into the skin) are often the outcome of shaving with an old blade.

Again, an unsharpened razor won't remove hair evenly and can irritate the skin, increasing your chances of developing those pesky little razor bumps.

"Also, people tend to make more passes with a dull razor than a sharp one, exacerbating this condition," Dr. Ploch says.

Ironically, you have a greater risk of cutting yourself with a blunted blade than a super-sharp one.

Here's why: A dull razor tugs at your skin (rather than smoothly gliding over it to get rid of hair).

And an old "blade can also undergo chipping, which isn't necessarily visible to the naked eye," Dr. Ploch says. A chipped razor's edge means your strokes will likely be patchier, producing an uneven shave that can cause cuts.

"Because razors tend to live in warm, humid environments like bathrooms, they're the perfect hosts for fungi and bacteria," Dr. Ploch says. And the longer you keep them, the greater the number of creepy crawlies that'll accumulate on the blade.

"This, mixed with the increased risk of cutting yourself from a dull, uneven razor blade, increases our risk of infection," Dr. Ploch explains.

Double that if you're sharing the razor with someone else. Razors can transfer bacteria from one person's skin to another, and that bacteria could cause problems if it finds its way inside a cut.

To minimize microbial growth (and your odds of infection), don't share your razor with anyone else and store it in a cool, dry place "store razors in a cool, dry place [i.e., not the bathroom where water tends to collect or puddle]," Dr. Ploch says.

"How often we should change our razors depends on how often we shave and the size of the surface area that we are shaving," Dr. Ploch says.

A general rule is to replace razor blades after five to 10 shaves (or more frequently if you shave bigger body parts every day), she says.

In other words, if you're covering large patches of skin (read: your legs) with each daily shave session, the blade will become blunted more quickly and will need to be replaced more regularly.

A clean razor can help reduce your risk of infection. And all it takes to keep it hygienic is a little H2O.

"I recommend rinsing razor blades after each 'swipe' while shaving and then rinsing very well after each use," Dr. Ploch says.

And don't rub the blade on a sponge or towel, which can make it dull faster, Dr. Ploch says. Instead, gently pat the handle to flick off any excess water and let the razor air dry after each use.

What about a disinfectant? "Alcohol can help to decontaminate a blade, but wiping the blade can damage it," Dr. Ploch says. "Again, it's more important to change the blade out regularly and rinse it after use."

No good can come of shaving with an old, rusty razor. At worst, it can irritate your skin and cause an infection. At best, you won't get the smooth shave you're after. That's what we call a lose-lose situation.

So, do yourself a favor: Ditch the dull razor and start fresh with a sharp blade. Your skin will thank you for it.