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Skin-Pedia: Skincare Terms Defined

Rodan and Fields Radiant Defense Perfecting Liquid - pictured with pitri dishes of ingredients

Do you ever feel like skincare is its own language? It’s not lingo, it truly is a vocabulary of medical terms, ingredient names and skin conditions. Want to speak skincare? Here are a few of the more common and interesting terms defined.

ACNEGENIC — A way to describe a product that has been tested and found to clog pores and promote acne. On the other hand, non-acnegenic is what you want to look for, it means it won’t cause acne, like Radiant Defense Perfecting Liquid, that’s one of the many great things about this skin perfector.

AGE SPOTS — These brown spots are actually hyperpigmentation, which is increased abnormal melanin pigmentation (color) in the skin. Sun exposure is a major culprit in creating age spots, which is why we always suggest wearing sunscreen. REVERSE Brightening Regimen is designed to tackle a full range of discolorations from uneven skin tone to age spots and melasma.


BENZOYL PEROXIDE — A treatment that kills the acne bacteria on the skin and in the pores. It’s our preferred anti-acne agent for long-term control of acne. Both our UNBLEMISH Regimen and SPOTLESS Regimen contain Benzoyl Peroxide. In fact, SPOTLESS contains more Benzoyl Peroxide and oxygen that starts killing acne bacteria on Day 1.

BLACKHEAD — A clogged pore that is open to the air and the oil becomes oxidized, causing it to turn gray to black, or darker in appearance. Oxidation also causes rust on iron. Just saying.

COMEDOGENIC — Similar to acnegenic, this means products that have been tested and found to clog pores and promote acne. And yes, Radiant Defense is also non-comedogenic, so it won’t clog pores.

CYSTIC ACNE — Large, red, painful bumps that are very deep under the surface of the skin and often spread. This form of acne is caused by closed, clogged pores where bacteria proliferates and inflammation forms. Unfortunately this type of acne needs the attention of a dermatologist to get it under control and prevent scarring.

FOLLICULITIS — This is a condition showing up as pesky little red bumps at the base of the hair, or hair follicle. It’s most often caused by a bacterial infection of the hair follicles, or by a virus, fungi or inflammation from ingrown hairs. Shaving can cause ingrown hairs, commonly found on the legs and groin. But sweaty exercise clothes can also contribute to folliculitis if you wear them too long.

MELASMA — This refers to patches of discoloration, often around the outer face or upper lip. It happens when there’s an increase in estrogen-type hormones, so birth control pills, hormone replacement therapy or pregnancy can cause it (which is why it’s often called “the mask of pregnancy”). Sun exposure makes it worse. Try REVERSE Lightening Regimen if this is your concern, it’s designed to help gradually fade dark marks, patches and age spots while reversing sun damage and discoloration.

MOISTURE BARRIER — It’s true, there’s a naturally protective barrier on your skin’s surface. It’s made up of the outermost layers of the skin and natural lipids and fluids, and it helps keep out irritants. Too much scrubbing or harsh ingredients in products can disrupt the barrier. If that has happened, we recommend the SOOTHE Regimen to help replenish your moisture barrier.

OXIDATIVE STRESS – The act of free radicals (oxygen-containing molecules) seeking out healthy cells and damaging them. This activity breaks down collagen and increases other aging effects and health of entire body. Antioxidants like Vitamin C and E help reduce oxidative stress by preventing oxidation, which produces the free radicals in the first place.

PEPTIDES — These are amino acids that make up proteins, such as collagen, on the skin. When used in products, Peptides are powerful conditioners (and very expensive). Our REDEFINE Regimen incorporates them in our formulas as a way to visibly smooth lines and wrinkles and firm the appearance of skin.

RETINAL — Retinal is an ingredient in our proprietary Retinal-MD Technology found in our REDEFINE Intensive Renewing Serum; it’s a form of Vitamin A, more powerful than Retinol. They are both retinoids, which have been proven to reduce the appearance of lines and wrinkles. Retinoic Acid or Tretinoin, which people know by the brand names Retin-A or Renova, are prescription forms of Vitamin A and are regulated drugs.

SPIDER VEINS – Spider veins or telangiectasias are tiny purplish streaks that are most commonly seen on the outer thighs, ankles, and behind the knees as well as on the face, neck, upper chest and arms. Often, they appear during pregnancy when blood vessels stretch to compensate for the extra blood flow that is going to the baby.

STRATUM CORNEUM – The outer layer of dead skin that acts as a physical barrier, like shingles on a roof, to keep environmental aggressors and toxins out. It can be compromised by dehydration or sun damage.

WHITEHEAD – A clogged pore that is closed with skin cells covering it. Our anti-acne Regimens UNBLEMISH and SPOTLESS include exfoliation so a buildup of dead skin cells is avoided.