With nail art frenzy in full force, chances are you are paying more attention to your fingertips than ever before and how they measure up against the latest DIY manicures your friends are Instagramming. Which means you’re probably very in tune with the imperfections that make your canvas not so ideal for your newest paint job. Splitting, breaking, peeling—there’s a lot of things that can go wrong. But why?

A quick science lesson: Nails are composed of very small cells called onychocytes, which are mainly made up of keratin, says Dana Stern, M.D., a New York City-based dermatologist who specializes in nails and nail disorders. “If you were to look at the nail under a microscope, it actually looks almost like layered roof shingles. So these cells are very delicate and the nail is actually extremely absorptive,” she says. “It’s about 10 times more absorbent than skin.”

Which is why when you take a long bath, your nails get super soft and bendy.It’s important to note that if your nails become extremely brittle out of nowhere, it could be a sign of a health issue, such as anemia, or a thyroid condition, says Stern. If that’s the case, you should see your doctor. In addition, those who suffer from an eating disorder or are undergoing chemotherapy may have chronic brittleness due to severe protein deficiency. If you don’t have any of these health woes but have had weak nails for as long as you can remember, it could be genetic. “If your mother has brittle nails there’s a good chance you’re going to have them, too,” Stern notes.

Nails’ absorbent nature also makes them susceptible to many external factors, all of which can cause them to break and split. Here are the three biggest culprits that Stern notes could be messing with your nails:

Water Exposure:
When you wash your hands or take a bath—or even get a manicure—water is absorbed into your nails. Then eventually, that water diffuses back out. This constant change in water content causes the cells to expand and contract, straining them as they continually change size to accommodate more or less water.

Seasonal Weather Changes:
In the winter, your days are spent going from a 70-degree indoor environment to a cold, below-freezing outdoor environment. And with the changing temperature comes varying levels of humidity. Just like your body temperature adjusts to these dramatic temperature fluxes, so do your nails. “The water content of the ambient environment is in flux, and so is the water content of our nails,” Stern says, which causes the same type of strain and weakening that water exposure does.

Chemical Exposure:
From this point forward, consider nail polish remover the enemy. “Polish remover is really a solvent—it’s strong, almost like a paint thinner—and it really dries out the nail,” Stern says. The most offensive chemical is acetone, but that doesn’t mean non-acetone removers are a whole lot better. “The non-acetone version requires more of the liquid and more exposure time,” she points out. So although it’s not as harsh, drenching your nails in more product and rubbing more aggressively to remove stubborn polish is still damaging. No formal study has been done on which is actually better, but Stern suggests that forgoing acetone might be the better route.

As for polish itself, Stern says that it can actually help hold the delicate nail cells together, preventing the tips from peeling. The problem is that eventually you have to take it off. And you should never ever pick it off. “The problem with picking off polish is you’re not only taking off the polish but you’re also taking off the top layer of nail cells,” says Stern. Which can be an issue with gel manicures if you’re not going into a salon to get them removed properly.

Regain Your Strength:
Luckily, it’s pretty easy to protect nails against these damaging factors. Try Stern’s simple suggestions that can help create a healthy environment for your nails to grow long and strong:

  1. Wear gloves when handling any chemicals, doing the dishes or hand-washing clothes to avoid water exposure.
  2. Steer clear of alcohol-based hand sanitizers. They’re very drying. Instead, wash hands with moisturizing soap.
  3. Keep your nails short to minimize surface area where water and chemicals can be absorbed.
  4. “The only supplement that has any scientific evidence [to improve nail health] behind it is biotin,” Stern says. Nails take six months to replace themselves, so she suggests taking biotin supplements for at least four to see if it works.
  5. Use cuticle oil or cream to avoid dry skin and hangnails. Cuticles help prevent water from getting into your nails, which can create an environment for bacteria to grow. So don’t cut away at them—keep them moisturized and simply push them back to avoid infection and let them do their job.
  6. Take a nail polish holiday. If you’ve tried other precautions and still are suffering from brittle nails, take a break from polish to give your nails some time to get back into shape. How long is appropriate? “Nails grow slowly so unfortunately it takes time,” Stern says. “I’d say consider a three month holiday.”

Plus, check out our recommendations for products that can help strengthen and repair weak and brittle nails.