[Primary safety — Phototoxicity + Dermal limits] Tisserand R & Young R. Essential Oil Safety, 2nd Ed. Churchill Livingstone, 2014. p. 339 — Bitter orange expressed phototoxic; max leave-on 1.25%; avoid UV 12–18h.
[Comprehensive review — Chemistry + Bioactivity] Maksoud S, Abdel-Massih RM, Rajha HN et al. "Citrus aurantium L. Active Constituents, Biological Effects and Extraction Methods. An Updated Review." Molecules 2021;26(19):5832. DOI: 10.3390/molecules26195832. PMID: 34641373
[GC/MS Peel oil — Limonene 94.81%] Sanei-Dehkordi A et al. "Chemical Compositions of the Peel Essential Oil of Citrus aurantium and its Natural Larvicidal Activity." J Arthropod-Borne Dis 2016;10(4):425–432. PMC5186748. PMID: 27774053
[Overview p-synephrine + anti-obesity] Suntar I et al. "An Overview on Citrus aurantium L.: Its Functions as Food Ingredient and Therapeutic Agent." Oxid Med Cell Longev 2018;2018:7864269. DOI: 10.1155/2018/7864269.
[Chemistry + furanocoumarins review] González-Mas MC et al. Front Plant Sci 2019;10:12. DOI: 10.3389/fpls.2019.00012. PMID: 30804951
[Virucidal activity GC/MS] Hirasawa M et al. "Virucidal Activity of Essential Oils From Citrus × aurantium against Human Coronavirus." Nat Prod Commun 2022;17(1). DOI: 10.1177/1934578X211072713
[IFRA/CIR safety] CIR Expert Panel. "Safety Assessment of Citrus-Derived Peel Oils as Used in Cosmetics." Int J Toxicol 2014;33(2 Suppl):5S–28S.
[VN YHCT — Chỉ thực/Chỉ xác] Nhà Thuốc Long Châu. "Cam đắng (hoa và quả): Loài thực vật có tác dụng giảm cân." nhathuoclongchau.com.vn. 2024.
[VN taxonomy / origin] Wikipedia Tiếng Việt. "Cam đắng." Lưu ý: C. aurantium subsp. amara có nguồn gốc từ miền Nam Việt Nam.
[Data reliability] HIGH — Phototoxicity và giới hạn dermal (Tisserand/IFRA nhất quán); HIGH — Hóa học (multi-source GC/MS + systematic reviews); HIGH — VN YHCT context (chỉ thực/chỉ xác); MODERATE — Therapeutic EO (phần lớn dữ liệu từ extract toàn phần, không phải pure EO)