Merck Manuals 发布防晒霜类型指南：化学与矿物防晒怎么选

, /PRNewswire/ -- When it comes to safeguarding your skin from the sun, sunscreen is an important part of year-round protection. Yet not all sunscreens are created equal. Getting the necessary protection depends on choosing the right kind of sunscreen.

In a new editorial from MerckManuals.com, Jonette E. Keri, MD, PhD, University of Miami, Miller School of Medicine, shares key information about different types of sunscreens, including chemical and mineral varieties. She also shares sunscreen usage tips.

Chemical versus mineral sunscreens

Sunburn results from a brief overexposure to ultraviolet (UV) light. Most sunscreens are designed to protect against UVA and UVB light, says Keri. Chemical sunscreens work by absorbing UV rays and converting that energy into heat. Mineral or barrier sunscreens, which contain zinc oxide or titanium dioxide, work by reflecting both UVB and UVA rays.

Some people have concerns about the safety and absorption of sunscreen ingredients, says Keri. Studies have shown some systemic absorption of certain chemical sunscreen ingredients, but there is no current evidence that this is harmful to humans. Others may have similar concerns about systemic absorption of nanoparticle mineral-based sunscreens. People concerned about the effects of absorbed nanoparticles may prefer to use so-called "non-nano" mineral sunscreens, says Keri.

More details on bemotrizinol

One sunscreen ingredient in particular has been the subject of headlines in the United States recently. Bemotrizinol is a chemical blocker that has been used as a sunscreen ingredient in Europe and other parts of the world for years, says Keri. In June 2026, the FDA approved bemotrizinol for use as an over-the-counter sunscreen active ingredient.

This single ingredient provides both UVA and UVB coverage. Bemotrizinol is also more stable when exposed to sunlight than currently available UVA sunscreen ingredients in the United States. And because it is a larger molecule, there is very little absorption through the skin, says Keri.

Sunscreen usage tips

Ultimately, the best sunscreen is the one you're going to use, says Keri. But for best protection, use a broad-spectrum, water-resistant sunscreen with an SPF rating of 30 or higher.

Here are a few additional sunscreen tips:

• Reapply sunscreen every two hours and immediately after swimming, sweating, or drying off.
• If using a spray-on product, apply outdoors to avoid inhaling the product.
• Use enough sunscreen for adequate protection – roughly the amount of a shot glass full for the body and a quarter-sized amount for the face and neck.
• Make sure to apply sunscreen to often-forgotten areas, such as the scalp and hairline, ears, backs of the hands and tops of the feet.

To read more of Keri's insights on sunscreen and sun protection, visit the editorial at MerckManuals.com.

About The Merck Manuals and MSD Manuals

First published in 1899 as a pocket-sized reference for physicians and pharmacists, The Merck Manual has evolved into one of the world's most trusted and widely-used medical resources. Today, it serves professionals and consumers alike with expert-authored, regularly updated medical content. Available in 16 languages and reaching nearly 250 countries, The Manuals offer far more than text. The website and mobile apps feature an ever-growing collection of videos, podcasts, infographics, and interactive 3D models designed for medical professionals, students, veterinarians, and curious consumers. For over a century, The Merck Manual has been fully committed to making reliable medical knowledge accessible to everyone, everywhere. Access The Manuals online in the United States and Canada at MerckManuals.com, and worldwide at MSDManuals.com. 

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

SOURCE The Merck Manuals