Is It Permissible to Wear Tzitzit Directly on the Body?

Greetings, In principle, it is permissible to wear tzitzit directly against the skin without the interruption of an undershirt. Still, it is advisable to be stringent in this regard to avoid any semblance of disrespect toward the mitzvah. Sources: In Sefer Hilchot Shlomo, Part I (Chapter 3, Paragraph 11), it is written that one may wear a tallit katan on bare skin, and this is not considered a degradation of the mitzvah since it was customary to wear them as one wears other clothing. This is also the view of Or LeTzion, Part II (page 29, under the heading 'And in any case'). Likewise, the Mishnah Berurah, Part I (Siman 8, Biur Halacha, Paragraph 14), quoting Rabbi Ovadia Yosef, zt"l, rules that in principle leniency is permitted. However, contrary to this, see Shevut Yisrael, Part IX (Siman 1), which holds that fashioning the four corners from a garment close to the body called an undershirt — which becomes sweaty in summer and is made for that purpose — constitutes a form of disrespect toward the mitzvah of tzitzit, and it is incorrect to do so. Similarly, this is explained in Shevut VeHanhagot, Part I (Siman 25), where it is stated that this is not an enhancement of the mitzvah. See also Rabbote Ephraim, Part IV (Siman 15, Paragraph 1).