Many sun creams contain food items that were grown in Eretz Yisroel, and presumably based on the din of sicha keshtiya [anointing is considered drinking] it should be forbidden to smear such a cream on oneself. Moreover, even if there is no concern of sicha keshtiya, it is prohibited to benefit from produce which needs to have terumas and ma’asros separated from it, in a destructive manner (see Gemara Shabbos 26a, and Rambam Hilchos Ma’aser 6:2, where it says it is forbidden to light Shabbos candles using oil which needs to have terumas and ma’asros separated from).
There is a well-known Biur Halachah (326) who brings a machlokes Rishonim if one is allowed to use soap which contains forbidden fats inside, and if we are worried about sicha keshtiya. The Biur Halachah writes, that the general custom is to be lenient, however, there a few individuals who are careful not to, and it is certainly a good thing to be concerned about. However, in our case it would seem everyone would agree one may be lenient. The Chazon Ish (Demai 15:1) maintains that if tevel [un-tithed produce] is no longer fit for human consumption, it no longer has a name of tevel, even if it is still fit for animal consumption or for anointing. Although there is a din that one isn’t allowed to benefit from tevel in a destructive manner, that’s only if it is still fit for human consumption, if it is no longer fit for human consumption, there is no longer a chiyuv to separate terumas and ma’asros, and therefore, it no longer has the status of tevel.
However, there is a sefer called Sha'ar Ho'ayin where he brings that he heard in the name of Rav Shteinman that he is machmir, however, he writes that he went to him and discussed the matter with in person and Rav Shteinman agreed “bepashtus” that one can be “meikel”.
