Retinoids: The best cosmeceutical on the market

July 1, 2005

New Orleans — Myths and misconceptions distort the truth about retinoids and lead to underuse, says Nia Terezakis, M.D., clinical professor of dermatology at Tulane University Medical School in New Orleans and a clinical associate professor at Louisiana State University in Baton Rouge.

New Orleans - Myths and misconceptions distort the truth about retinoids and lead to underuse, says Nia Terezakis, M.D., clinical professor of dermatology at Tulane University Medical School in New Orleans and a clinical associate professor at Louisiana State University in Baton Rouge.

She adds, "Over 40 years of research have been invested in retinoids. More and better ones are coming on the market. Not only do they work, they're the best cosmeceutical on the market."

Dr. Terezakis describes retinoids as a class of vitamin A derivatives that are essential to normal hair, skin and nails. Topical use speeds up the epidermal turnover rate from 30 to 35 days to five to six days. Retinoids also repair DNA in epidermal cells, stimulate new collage production, repair small blood vessels, reduce pore size and shrink oil glands.

Dispelling myths Many patients and dermatologists believe retinoids should be applied conservatively, no more than once a day. But Dr. Terezakis argues they may be applied as often as a patient can tolerate the treatment. She starts with an every-other-day regimen, progressing to daily and then multiple applications a day - again, if tolerated. Reduce the application rate or concentration if irritation occurs.

For cosmetic benefits and acne treatment, the dermatologist says, "The key is to deliver as much of the active ingredient as often as possible."

Retinoids are widely believed to cause sun sensitivity. The reality is that initial use thins the stratum corneum due to exfoliation. This, not a photochemical reaction, induces temporary sensitivity to sun. With continued retinoid use, the skin will thicken, and sensitivity will fade over a three- to four-month period. In combination with daily use of sunscreens (SPF of 15 to 30), retinoids are actually chemopreventative and chemotherapeutic.

Some patients are reluctant to use retinoids because of rigid ideas about when and how they should be applied: at night, for example, 20 minutes after washing the face.

But the most important factor is developing habits that encourage consistent, long-term use. Retinoids bond very quickly to the stratum corneum and are unlikely to be inactivated unless a patient heads directly to the beach after morning use. The dermatologist points out that most people go to school or work.

Many people think retinoids dry the skin. Dr. Terezakis explains that exfoliation may look like dry skin but isn't that at all. Rather, it's the skin's normal process of sloughing dead and damaged cells. Besides, dryness doesn't age skin. Only sun and birthdays do that.

Retinoids should not be mixed with moisturizers, because water inactivates them, especially in combination with sunlight. If a patient prefers to use a moisturizer after a retinoid, advise her or him to wait awhile and to use an "educated" moisturizer - one with alpha hydroxy acid, alpha lipoic acid or idebenone, for example.

Another misconception is that retinoids should not be applied to eyelids, neck or lips. Dr. Terezakis holds the opposite opinion: They can be applied to these areas for improved cosmetic appearance.

"The skin around the eye irritates more easily but it won't harm or blind anyone if they get it in their eyes," she says.

Finally, Dr. Terezakis advises dermatologists not to compare products solely on the basis of the active ingredient's concentration, because the vehicle is a critical factor in overall efficacy.

Disclosure: Dr. Terezakis is an owner of and clinical consultant to Advanced Skin Technologies, which produces an over-the-counter retinoid called Green Cream.