2937.23 - Estrogens and progestins:

This category, HTS Code 2937.23, encompasses a broad range of synthetic or naturally derived hormones primarily functioning as estrogens and progestins. These substances are crucial in various pharmaceutical applications, including hormone replacement therapy and contraception. The classification focuses on the specific hormonal activity of estrogenic and progestogenic compounds, distinct from other steroidal hormones.

Unlike sibling categories such as 2937.21 (cortisone, hydrocortisone, prednisone, and prednisolone) or 2937.22 (halogenated derivatives of adrenal cortical hormones), HTS 2937.23 is specifically for hormones that mimic the effects of female sex hormones. While those siblings deal with corticosteroids and their derivatives, this code is reserved for compounds directly related to estrogen and progesterone functions.

The subcategories under 2937.23 further refine the classification based on the origin and processing of these hormones. Subcategory 2937.23.10 specifically covers estrogens and progestins that are obtained directly or indirectly from animal or vegetable sources, indicating a reliance on natural extraction. The "Other" subcategory will capture all remaining estrogens and progestins not derived from natural materials, thus including purely synthetic compounds or those processed through chemical synthesis not covered by the "obtained from" clause.