With many praying outside on Shabbat, rabbis are frequently asked whether we are permitted to use sunscreen on Shabbat. The issue centers on the topic of memarei’ach.
Memarei’ach refers to “smoothing soft, pliable substances that may be pressed or molded to a shape” (Rav Dovid Ribiat, The 39 Melachos, 3:913). A prime example of this is the Mishnah (Shabbat 22:3) that forbids spreading wax to seal a hole in a barrel. The Gemara (Shabbat 146b) records a dispute between Rav and Shmuel whether this prohibition also applies to spreading oil to seal such a hole. Rav asserts that it is a rabbinic prohibition to spread oil lest one come to spread wax. In contrast, Shmuel permits this activity, as he does not see the necessity for creating such a gezeirah (rabbinic enactment). The halacha follows Rav (Rambam Hilchot Shabbat 23:11 and Shulchan Aruch O.C. 314:11), as is the usual protocol in the context of ritual matters (issurei). Rav Ribiat (The 39 Melochos 3:919) writes that rouge creams, eye-shadow creams, petroleum jelly, and hand creams such as Nivea and Desitin are included in this rabbinic prohibition.
However, even Rav appears to concede that this rabbinic prohibition does not apply to all substances. Rashi (ad. loc. s.v. Mishcha) specifies that it applies only to thick oil, and the Shulchan Aruch (O.C. 314:11, as emphasized by the Mishnah Berurah 314:46), rules following Rashi. The Mishnah Berurah explains that since thick oil may be spread somewhat, it is similar enough to wax to necessitate the gezeirah, while thin oil does not resemble wax at all and therefore is permitted.
The question, then, is how to determine which items are considered “thick oils” to be included in this rabbinic prohibition. A classic illustration of this problem is the question of using liquid soap on Shabbat. The Aruch Hashulchan (O.C. 326:11), Ketzot Hashulchan (146:32), and Yalkut Yosef (Orah Chaim 326:14) permit the use of liquid soap on Shabbat, contending that liquid soap is not comparable to thick oil and thus is not subject to the prohibition of memarei’ach. Dayan Posen (Kitzur Hilchot Shabbat p. 74) notes that the common practice is to follow this lenient ruling. The Shemirat Shabbat Kehilchata (14:16) also rules by this opinion.
We should note, though, that Rav Moshe Feinstein (Teshuvot Igrot Moshe O.H. 1:113) expresses serious reservations regarding the use of liquid soap on Shabbat. However, Rav Moshe’s opinion is not followed by most observant Jews.
Based on the common practice to use liquid soap on Shabbat, Dayan Posen (ad. loc.; p. 147, 32:19) sets a standard for what items are included in the rabbinic prohibition of memarei’ach: Anything that is thick to the extent that it cannot pour, does not flow by itself, and needs to be smoothed out is similar to memarei’ach and is forbidden. Liquid soap is permissible since it pours, flows by itself, and does not need to be smoothed out.
Dayan Posen adds that since this is only a rabbinic prohibition for which the classic poskim present no objective standard, one has the right to adopt a limited view of its scope. Rav Ribiat (The 39 Melachos 3:920) takes this approach as constituting baseline halacha. Based on this standard, Rav Ribiat permits the use of baby oils, lubricating jellies and olive oil on Shabbat.
Sunscreen Use on Shabbat
Based on these definitions, one should avoid using sunscreen lotion on Shabbat. While a Torah-level prohibition is not violated since it is not a soft, pliable substance that may be pressed or molded to a shape like wax, it is forbidden on a rabbinic level. It is rabbinically prohibited since it is comparable to thick oil in that it cannot pour, does not flow by itself, and needs to be smoothed out. Spray sunscreen, however, is entirely permissible since it flows by itself and does not need to be smoothed out.
Postscript: Sunscreen Lotion In Hawaii on Friday
Many rabbanim recommend refraining from engaging in Torah-level prohibitions on Friday in Hawaii. This restriction is due to the opinions that believe that Friday is Shabbat in Hawaii (for a summary of views, see https://www.koltorah.org/halachah/lander-college-model-beit-din-2017-halachah-and-the-international-date-linetabcs-fourth-consecutive-victory-part-two-by-rabbi-chaim-jachter). Sunscreen lotion may be used on Friday in Hawaii according to these opinions since it does not constitute a Torah-level prohibition.
Rabbi Haim Jachter is the spiritual leader of Congregation Shaarei Orah, the Sephardic Congregation of Teaneck. He also serves as a rebbe at Torah Academy of Bergen County and a dayan on the Beth Din of Elizabeth.