12 Common Beauty Questions, Answered
1. Some creams come with a thin plastic lid under the cover. Should I keep it or toss it?
Keep it, says Mary P. Lupo, a dermatologist in New Orleans. Exposure to light and air breaks down many active ingredients, including vitamin C and retinol, making them inert. Also, store these products in a cool, dark place to help maintain their efficacy.
2. I add water to my shampoo to make it last longer. Will it clean as well?
If it’s a concentrated shampoo that really lathers up (and takes a lot of water to rinse out), there’s no harm in adding water, says New York City dermatologist Doris Day. A nonsudsy shampoo could become too watered down to remove oils.
3. How often do I need to wash my makeup brushes?
Many experts agree that once a month is fine. "Dip the brush in warm, soapy water—use shampoo or a mild bar soap. Rinse it, blot the brush with a clean towel, then use a blow-dryer to dry the bristles gently," suggests Ellen Marmur, a dermatologist in New York City.
4. Should I toss out my lipstick after having a cold?
No. You can use it safely after having a cold because that virus should die quickly. Plus, it can’t reinfect you. "Your body has built up antibodies against the virus," says Neil Schachter, a professor of preventive medicine at the Mount Sinai Medical Center, in New York City. But strep throat is another story. "These bacteria may be able to survive longer," says Schachter. So throw out the lipstick or you may risk reinfection.
5. I keep my cleansing puff in the shower. Does it matter if it never fully dries out between uses?
Yes. Moisture that lingers in a puff can be a breeding ground for bacteria. So after rinsing it, let it dry completely by taking it out of the shower and hanging it on a hook. Or, if you are extremely motivated, microwave it for 30 seconds between uses, says Leslie Baumann, a dermatologist in Miami Beach, Florida.
6. Can I use a loofah on a breakout?
It’s tempting to tackle bumps with one of these skin smoothers, but "vigorous rubbing with a loofah can make acne worse," says Sonia Badreshia-Bansal, a dermatologist in Danville, California.
7. Is it safe to line the inner rims of your eyes?
Two things to keep in mind: A steady hand is essential so you don’t poke yourself in the eye. And you can contaminate your liner if you have a budding eye infection and don’t realize it. (Once you put the cap back on, the germs can grow and thrive.) But this doesn’t mean you can’t rock this slightly rocker look if you want to. Just always sharpen the pencil after lining your eyes. That way, you’ll put it back in the cap in pristine condition. If you have a full-blown eye infection, throw out the liner to avoid recontamination.
8. Is it OK to use the same tweezers to pluck facial hairs and for first-aid needs, like removing splinters?
Yes, as long as you take the proper precautions. "What you’re pulling out of your skin can harbor fungi or bacteria that can cause irritation if deposited elsewhere," says Marmur. So clean tweezers after a first-aid task by boiling them for a few minutes. Between grooming sessions, wipe them down with rubbing alcohol.
9. Is it OK to store sunscreen or a lip balm with SPF in a glove compartment?
No, especially during summer. Once the car heats up in the sun, "high temperatures can cause the sunscreen’s active ingredients to degrade right in the container," says Badreshia-Bansal. And the lip balm will melt, to boot. "When you apply a degraded sunscreen or balm to your skin, you’re not getting the SPF that’s indicated on the bottle," she warns. "In fact, you might be applying nothing more than a thick moisturizer."
10. Can I leave a bottle of body moisturizer in the shower?
As long as you keep the lid tightly closed and use the product within six to eight weeks, says Dr. Day. Also, be sure to keep the shower curtain and door open to allow adequate ventilation between uses. Otherwise, dampness in the stall can promote the growth of bacteria, yeast, or fungi in the cream, especially if it's an organic product with no preservatives.
11. Can I mix products without compromising their effectiveness?
It's safe to mix retinoid creams and moisturizers in your hand and apply them in one swoop, but don't blend sunscreen with another product, because it dilutes the SPF. Layer them instead. Also, "never mix a product with salicylic acid, glycolic acid, or another alpha hydroxy acid with a hydroquinone, retinol, or vitamin C product," says Baumann. "The acids with break down these compounds," making them ineffective. And some combos can cause excessive exfoliation, giving you a rash.
12. I often apply makeup on the bus to work. Can it become contaminated?
Only if you use your fingers after touching surfaces that countless other hands have touched, says Lupo. If you use a clean applicator, sponge, or brush, your makeup isn't liable to get sullied. The greater risk? Poking your eye out. If you must do your face in transit, save tricky moves for stoplights.