Curcumen, derived from Curcuma species (such as Curcuma longa and Curcuma zedoaria), contains curcuminoids and related compounds. The primary active constituent, curcumin, has been investigated for its anti-inflammatory and immunomodulatory properties, which are relevant to respiratory allergies, such as allergic rhinitis and asthma. Several in vitro and animal studies indicate that curcumin can modulate immune responses by inhibiting the release of histamine from mast cells, reducing eosinophil infiltration, and downregulating inflammatory cytokines (e.g., IL-4, IL-5, and TNF-α) implicated in allergic reactions.

Human evidence, however, is limited. A few small clinical trials have suggested that curcumin supplementation may alleviate symptoms of allergic rhinitis by reducing nasal congestion, sneezing, and airway inflammation, likely due to its ability to inhibit NF-κB signaling pathways. However, these studies often have small sample sizes, short durations, and varying formulations and dosages, making it difficult to draw firm conclusions about efficacy. Additionally, the bioavailability of curcumin is generally low unless formulated with enhancers such as piperine.

In summary, the use of Curcumen (curcumin) for respiratory allergies is justified by promising mechanistic and preclinical evidence, with limited but suggestive clinical support. The evidence is not robust, so further well-designed studies are needed to confirm efficacy and establish optimal dosing.