Arabinogalactan, a polysaccharide derived mainly from the larch tree (Larix species), has been studied for its potential immunomodulatory effects, which is the primary rationale for its use during convalescence (the recovery period following illness). Scientific investigations have demonstrated that arabinogalactan can enhance immune system function by stimulating the activity of natural killer (NK) cells, macrophages, and the production of certain cytokines. Additionally, some research suggests that arabinogalactan may promote the growth of beneficial gut bacteria, contributing indirectly to improved immune health and recovery.

Several small-scale human studies and animal experiments have shown that supplementation with arabinogalactan may reduce the incidence and duration of upper respiratory tract infections, which are common during periods of weakened immunity or recovery. However, evidence specifically supporting its use for generalized convalescence (not limited to respiratory infections) is limited and not robust. Most clinical trials have focused on specific outcomes such as immune markers or response to vaccination, rather than broad recovery from illness.

In summary, while there is some scientific rationale and preliminary evidence supporting the use of arabinogalactan to support the immune system during convalescence, high-quality clinical trials directly validating its efficacy for this purpose are lacking. Thus, the evidence is rated as moderate but not strong (2 out of 5).