In a busy clinic day, I can only communicate with patients for a few minutes, and medical jargon often pops out of my mouth. Sometimes I say, “Don’t worry, it’s a soft hormone” when reassuring a hormone-phobic patient. The patient nods in confusion and takes the cream with him, but he may not know what kind of magic cream “soft hormone” is. Today, we will tell the story of “soft hormones”. The history of topical hormones This is the hormone produced in our body – hydrocortisone. In 1952, two dermatologists used hydrocortisone topically to treat dermatitis and eczema with good results. Dozens of topical hormone products have been used for more than half a century to treat skin diseases, all of which are chemically synthesized based on the structure of hydrocortisone. As we all know, unregulated topical hormones may cause various side effects: local side effects such as skin atrophy, capillary dilation, increased pigmentation and local hirsutism, etc.; systemic side effects such as the impact on the body’s internal hormone secretion regulation axis and the impact on blood sugar and blood pressure after topical application over a large area and absorption through the skin. Therefore, in the process of structural modification of topical hormones, the goal of scientists is to increase the efficacy of the drug as much as possible, while minimizing the local and systemic side effects of the drug. This has led to the emergence of an evaluation index: the therapeutic index. The larger the therapeutic index, the better. In the graph below, the closer to the upper left corner, the larger the therapeutic index, which means that the hormone product is more effective and has fewer side effects. How do soft hormones come about? Through a quantitative evaluation system like the Therapeutic Index, scientists evaluated most topical hormone products and found four products with the highest Therapeutic Index, which are marked in red in the table below: mometasone furoate (MM), methylprednisolone acetate (MPA), prednisolone (PC), and fluticasone propionate (FP). These four topical hormone products are often referred to as “soft hormones”. They are strong or medium-acting hormones in terms of anti-inflammatory strength, but they can be degraded by the esterase enzymes in the skin or quickly transformed and metabolized by the liver after application, so they have fewer side effects caused by systemic absorption and relatively few local side effects. Advantages of soft hormones There are currently two soft hormone products approved for use in mainland China: 0.05% fluticasone propionate cream and 0.1% mometasone furoate cream. The U.S. FDA (Drug and Food Administration) approved 0.05% fluticasone propionate cream for the treatment of atopic dermatitis in infants and children over 3 months of age. Studies have demonstrated that fluticasone 0.05% propionate cream for long-term maintenance treatment (i.e., active maintenance therapy, twice weekly for 16 weeks) of atopic dermatitis in children and adults is effective in reducing relapses, with no significant side effects of skin atrophy or systemic absorption. Fluticasone propionate 0.05% cream is safe for use in skin folds and on the face, including the eyelid area. The U.S. FDA (Drug and Food Administration) has approved 0.1% Mometasone Furoate Cream for the treatment of atopic dermatitis in infants and children over 2 years of age. 0.1% Mometasone Furoate Cream is also safe for use on the face and folds, and 0.1% Mometasone Furoate Cream is less likely to cause contact allergic reactions than other topical hormone products.