Your skin is not only the body’s largest organ, it's also its first line of defense against pathogens, microbes and other intruders. These invaders can more easily bypass the skin's protective barrier when it's dry and cracked (perhaps from dousing your hands with hand sanitizer all day, every day).

Help your skin do its job and prevent irritation by keeping it hydrated. But here's the thing: not all moisturizers are created equal when it comes to nourishing the skin and keeping it healthy.

Clean, effective oils are growing in popularity with wellness-savvy consumers, thanks to advantages such as hydration, rejuvenation and even targeting the appearance of fine lines and creases, says dermatologist Gary Goldfaden, MD. Below, three reasons oils are an important upgrade in your body-care routine.

Reason 1: No preservatives or mystery ingredients needed

"Studies have shown that our skin is capable of absorbing up to 60 percent of the ingredients applied," says Goldfaden, which is why it's so important to know what you’re putting on your skin regularly. Unfortunately, a number of body-care products on the market today can contain harmful ingredients such as preservatives, phthalates, mineral oils, alcohol, ammonium, and sodium laureth sulfate.

Body lotions often contain preservatives to maintain freshness. Although often "generally recognized as safe" by the FDA, research has shown that some of these common additives can be harmful to your health. For instance, the preservative, butylated hydroxyanisole (BHA), is “reasonably anticipated to be a human carcinogen" by the National Toxicology Program. It's also classified as an endocrine disruptor by the European Union, which means it can impact natural hormonal function.

Two other oft-seen preservatives, methylchloroisothiazolinone and methylisothiazolinone, have been banned from use in leave-on cosmetic products in the European Union. They have been linked to skin allergies and irritation and may be toxic to the lungs and nervous system, yet are still allowed in lotions and other cosmetic products in the U.S.

Another mystery ingredient: emulsifiers. Body lotion is basically made up of oils mixed with water, so emulsifiers (lab-produced substances used to stabilize a product) are needed to keep the oil and water from separating. Many lotions contain PEGs (polyethylene glycols) to serve as emulsifying agents. According to the Cosmetic Ingredient Review (CIR), the presence of impurities during or after the process of mixing these compounds is of concern, including 1,4-dioxane, ethylene oxide, and propylene oxide, which are known to be carcinogenic and/or highly volatile.

In contrast, body oils contain very few, easily understood ingredients. Many oils and essential oils also have antimicrobial properties that naturally protect against bacteria, so there’s no need to add extra preservatives to keep out the bad guys. THE WELL body oils also add in rosemary extract to naturally maintain the product's freshness. This kind of purity and transparency means there is nothing to hide.

Reason 2: Natural fragrance

THE WELL body oils are scented with 100-percent plant-based ingredients — including sustainably wild-harvested and organic essential oils — each of which you can find listed on the label.

The typical body lotion, however, is scented with chemicals. Fragrance has been a hot-button issue in the clean-cosmetics industry for decades, since Congress passed the federal Fair Packaging and Labeling Act in 1973, which required companies to list cosmetics ingredients on its labels — except fragrance.

This has turned fragrance into a "dirty word" in the beauty industry, Goldfaden says — a type of Trojan horse where companies can hide harmful synthetic ingredients under the non-descriptive term. Research by the Environmental Working Group found carcinogens, toxins and endocrine-disrupting parabens hiding in the "fragrance" found in many prestige and mainstream lotion brands.

Another concern in the fragrance discussion centers around phthalates, which are a class of chemicals that help carry and stabilize scent in the air. Phthalates have been shown to cause reproductive and developmental harm in laboratory animals, and are linked to similar impacts in humans.

Reason 3: Healthy nourishment

Many mass-market lotions are made of mostly water, making them less hydrating and more likely to rub off quickly, Goldfaden says. What's more, many body lotions can't penetrate the lipid barrier of skin very well, due to the large size of the molecules in the petroleum-derived moisturizing agents.

In contrast, "oils tend to offer a more concentrated form of moisture than traditional body lotions, locking in and enhancing hydration for longer-lasting rejuvenation," Goldfaden explains.

Plus, plant-based oils may offer higher absorption abilities possibly due to the smaller molecules found in the oil that may allow them to more effectively moisturize, Goldfaden says. "They in turn may nourish, lubricate, and rejuvenate the skin's top-most lipid protective barrier and may lock in moisture for longer results."

THE WELL body oils have lipids of varying sizes, which both sit on the surface of the skin and penetrate. Triglycerides from almond and avocado moisturize the skin, while the oleic acid in coconut oil helps penetrate. Sea buckthorn oil, another carrier oil used in THE WELL body oils, is rich in both phospholipids and omega-3, -6, -7, and -9 fatty acids, which studies have shown to have protective, skin-nourishing benefits.