01/18/2013 12:30 pm ET | Updated Mar 10, 2015

Skin Care Products: What 'Natural,' 'Hypoallergenic' And 'Unscented' Really Mean

By Jenny Bailly

Don’t be fooled by these buzzwords: Four of the most common claims you see on skin care products can be misleading. Dermatologist Leslie Baumann, MD, tells us what these popular terms really mean.

1. 'Unscented'
What you think it means: Free of any fragrances.
What it really means: The product doesn’t have a detectable odor -- but may contain fragrances to mask its natural scent. If you’re trying to avoid fragrance ingredients (which are the most common allergens found in skincare products), “fragrance-free” is a better label to look for -- although it, too, can be tricky. “If the primary reason for including a fragrance is not related to scent -- some fragrances, for example, can act as preservatives -- then a product may still be labeled fragrance-free,” says Baumann.
What to look for instead: If possible, test products labeled fragrance-free on your inner wrist and wait a day to see if you have any reaction. You can also scan ingredient lists for the most common fragrances that cause allergies: cinnamic alcohol, cinnamic aldehyde, eugenol, hydroxy-citronellal, geraniol, isoeugenol, and oak moss absolute.

2. 'Natural'
What you think it means: Contains only -- or mostly -- plant and mineral ingredients.
What it really means: Whatever a manufacturer wants. There is no standard for the term “natural,” so each brand uses it however it wishes. On some labels, “natural” means that a product contains one or two essential oils (plus a whole lot of high-tech ingredients); on others, “natural” really does describe a formula without any synthetic ingredients.
What to look for instead: If synthetic-free beauty products are important to you, look for one of several green seals that are regulated by third-party organizations. To earn the USDA’s Organic designation, for example, a beauty product must contain at least 95 percent ingredients that are certified organic (natural and grown without certain pesticides or fertilizers) by the Department of Agriculture’s National Organic Program. (Check out our guide to this and three other seals you might see in the beauty aisle.)

3. 'Firming'
What you think it means:Proven to make skin look more taut.
What it really means: Essentially nothing. “There is no objective way to measure firming,” says Baumann. “When a brand says their product has been shown to firm your skin, that claim can only be based on very subjective consumer perception.”
What to look for instead: When your skin feels plump, it also feels -- and looks -- firmer. And the most effective way to plump your skin is with a good moisturizer. Your best bets are creams and lotions with humectants like hyaluronic acid and glycerin. Products that contain sugars will also temporarily smooth and tighten the skin; look for dextrose, sucrose, or other -oses on the ingredients list.

4. 'Hypoallergenic'
What you think it means:Won’t cause an allergic reaction.
What it really means: Often not much. To determine if a product is “hypoallergenic,” a company should perform patch tests on 100 to 200 subjects and wait several days -- even weeks -- to see how their skin reacts. “Hypoallergenic” has no official definition, however, and the extent of any testing completed varies widely.
What to look for instead: Because there is not one type of “sensitive” skin, consider avoiding the specific ingredients that are most likely to cause a reaction in your skin. If you’re acne-prone, for example, stay away from isopropyl myristate and coconut oil. If products often make your skin sting, don’t use anything with lactic acid, glycolic acid, azelaic acid or benzyl alcohol. If you suffer from itchy rashes, look for formulas free of fragrances, cetyl alcohol and parabens. (To find out more about which skin sensitivities you’re prone to, take Baumann’s quiz at skintypesolutions.com.)

Click through the slideshow below to find out how long you can keep makeup products before they get too germy.

Makeup Germs