So how exactly do you double-cleanse? Bowe explains, “For the first step, start with an oil-based cleanser to remove your makeup and dirt, pollution particles, etc., from your day. For the second step, you follow your first cleanse with a gentle, pH-balanced cleanser.”

Yahoo Beauty asked Bowe, who recently teamed up with skin care brand Dermalogica to promote its new PreCleanse Balm (available in September), to explain which skin types can truly benefit from washing their face twice, as well as the downside of chasing that “squeaky clean” feeling. Here’s what we learned:

If you have oily skin or suffer from acne, double-cleansing is one of the best ways to remove excess sebum and buildup.

“Double-cleansing allows the initial grime, makeup, pollution, and dirt from your day to be effectively and gently cleansed,” says Bowe. “I always explain to my patients that ‘like dissolves like.’” So she recommends using a gentle, oil-based cleanser to combat excessive oil, minimize breakouts, and thoroughly break down makeup and skin care products that are also formulated with oil.

If you have dry skin, eczema, or psoriasis, Bowe advises following your double-cleanse with a rich moisturizer and double-cleansing only about three times a week. She adds, “It’s also important to only double-cleanse at night, especially for people with preexisting conditions or sensitive skin.”

The dermatologist also suggests double-cleansing if you wear heavy makeup — particularly stage, screen, and TV performers — because it’s a much gentler way to remove makeup residue and maintain the health of your skin’s barrier.

If you live in an urban area, you too can benefit from this cleansing method. “Pollution levels tend to be higher in cities, and those tiny pollutant particles can dive into your pores and create free radical damage, which in turn promotes brown spots and premature aging,” says Bowe. “Thus, people who are prone to problems with pigmentation or uneven skin tone are ideal candidates for double-cleansing.”

Aggressive cleansing routines can create tiny tears in the skin.

According to Bowe, overcleansing is a key cause of many skin issues these days. She adds, “Many of my patients use scrubs, loofahs, and harsh washcloths to cleanse their skin, and they rub and scrub to get that ‘squeaky clean’ feeling.” This can pierce your skin, impair its ability to hold moisture, and block allergens and irritants from entering and triggering inflammation.

“Your skin should not feel tight or dry after cleansing,” says Bowe. To prevent or minimize further damage, use your fingertips to massage cleanser onto your face and neck in an upward motion.

In the morning, try using a pH-balanced water-based cleanser. Stay away from antibacterial cleansers or harsh soaps. “Both can actually disrupt the skin barrier and eventually lead to overgrowth of unhealthy bacteria on the skin,” says Bowe. “In fact, soaps that are basic (pH higher than 7) tend to create inflammation, dry out skin, and promote collagen degradation.”

This is why Bowe is a fan of Dermalogica’s PreCleanse Balm “because it locks in your skin’s hydration, maintains the health of your skin’s barrier, and is so effective in only one application.”

Over time, double-cleansing can slow down signs of the aging process by ensuring that free radical damage is minimized.

Sounds a bit far-fetched, we know. But double-cleansing acts like a primer to prepare your skin to absorb the full benefits of the antioxidants and other powerful ingredients in your serum and moisturizer, according to Bowe. “If you wait too long between cleansing and applying your serum and cream, you’ve missed that window to trap needed moisture in the skin,” she explains.

Allow us to break it down with this simple calculation: Double-cleansing + hydrating skin care = youthful-looking skin.