NEW YORK — In patients with darker skin types, particularly those who already have hyperpigmentation, iron oxide or antioxidants that protect against visible light represent a variable for efficacy that must be considered independent of the sun protection factor (SPF), according to an expert who is concerned this fact is often overlooked.

It is broadly understood that a high SPF is an important measure of photoprotection, but for those with skin types IV, V, and VI, unlike those with lighter skin types, blockade of ultraviolet (UV) light at high levels of SPF is not enough, according to Susan Taylor, MD, professor of dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia.

In skin types IV-VI, “an SPF of 30 is probably sufficient, but we want to make sure — we recommend — that sunscreen employs iron oxide and/or a combination of specific antioxidants to block visible light,” Taylor said.

Threat of Visible Light to Dark Skin Is Underestimated

This is not a new discovery. Research that supports the threat of visible light to darker skin has been available for years, and Taylor has published on this topic repeatedly. Yet she believes the importance of tailoring sun protection for darker skin has yet to be fully embraced.

In the context of an update about the ongoing evolution in sun protection, Taylor reiterated this point at the Skin of Color Update (SOCU) 2025.

On the electromagnetic radiation spectrum, UV light, which includes UVB and UVA wavelengths (290-400 nm), has long been known to be damaging. These can cause photodamage in all skin types and are the target of most commercial sunscreens. The visible light spectrum (400-700 nm) is also an important source of damage and dyschromia in darker skin but is less commonly targeted.

After exposure to visible light, hyperpigmentation and erythema in darker skin types develop rapidly but resolve slowly, Taylor said. The problem is shared by all individuals with dark skin, but the problem is particularly serious — and can be more difficult to reverse — in those with darker skin tones who already have sun damage and those at a risk for hyperpigmentation from other sources, such as an inflammatory skin condition.

To protect patients with darker skin, it is not enough to recommend sunscreens that do not block visible light regardless of SPF, Taylor said.

Of multiple studies that support the risk of visible light, one published earlier this year enrolled women with skin types III-VI. It included a subgroup who entered the study with melasma. The comparison was between SPF50 sunscreen with iron oxide to block visible light and one without.

Photodamage overall was significantly reduced in the group who used the sunscreen with iron oxide, and the effect was even more marked in the subgroup with melasma. The study not only measured this objectively but also measured quality of life with a self-assessment questionnaire, and it documented greater patient satisfaction.

Iron oxide sunscreens are tinted in order to better block visible light based on the principle that effective blockade of visible light must be visible itself. To the extent that iron oxide products can be modified by the degree of oxidation, the color of sunblock products that contain iron oxide can sometimes approximate the patient’s own skin hue, Taylor noted.

Antioxidant Combinations Can Also Block Visible Light

The alternative to iron oxide in sunscreens that block visible light are products that are formulated with antioxidants, such as vitamin E and vitamin C or their derivatives, which also protect the skin from light waves in the visible range. Several such products are now available, according to Taylor.

From the once relatively narrow goals of preventing sunburns and skin cancer, the evolution in sunscreens is now extending to protection against photoaging in both light- and dark-skinned individuals, she said. This includes already available products aimed at reducing the heat damage associated with infrared light (> 700 nm), such as cooling agents with hyaluronic acid as an active ingredient and products that rely on Polypodium leucotomos to block infrared light and possibly visible light as well.

Even if patients are prescribed the appropriate sunscreen for photoprotection, there are two practical issues that impair efficacy, Taylor said. One is that the recommended dose is 2 mg/cm², but there is substantial evidence that this recommendation is not followed routinely, leaving patients vulnerable to avoidable sun damage.

The second is that a substantial proportion of individuals with darker skin continue to believe that they are at a low risk for sun damage. Taylor, an internationally recognized expert in sun protection, commented that she recently had to urge a family member to apply sunscreen when they were both spending time exposed to the sun.

The damage from visible light in dark skin types is a potentially important public health issue because it is the source of avoidable morbidity. In these individuals, Taylor emphasized the importance of explaining the goals and benefits of sunscreen and the specifications of sunblock products most appropriate by skin type.

This is a message that cannot be repeated too often, Seemal Desai, MD, told Medscape Medical News. Desai, who also spoke at the meeting, is director of Innovative Dermatology in Plano, Texas, and has an academic affiliation with the University of Texas Southwestern Medical Center in Dallas.

“This is very important information,” added Desai, who was the president of the American Academy of Dermatology (AAD) until Taylor assumed the role at the last AAD meeting in March. He agreed that tailoring sunscreen choices for skin type is not being performed uniformly and urged clinicians to educate patients with dark skin types about the specific goals of sun protection and the agents that are best for them.

Taylor reported having financial relationships with AbbVie; Arcutis Biotherapeutics; Armis; AVITA; Beiersdorf; Biorez, Inc.; Bristol Myers Squibb; Cara Therapeutics; Dior; EPI Health; Estée Lauder; Evolus; Galderma; Dermavant; Glo Getter; Hugel; Incyte; Johnson & Johnson; Lilly; L’Oreal; Piction Health; Sanofi; Scientis; UCB; and Vichy Laboratories. Desai reported having financial relationships with AbbVie, Beiersdorf, Incyte, and Pfizer.