Fenugreek (Trigonella foenum-graecum) seeds and their fiber have a long history of use in traditional medicine, particularly in Ayurveda and Unani systems, where they are reputed to support women's health, including breast health and lactation. The traditional use most closely associated with the breasts is as a galactagogue—an agent that promotes or increases breast milk production in lactating women. Historical records and ethnobotanical surveys indicate that fenugreek has been used for centuries for this purpose in various cultures. However, these practices generally refer to fenugreek seed preparations as a whole, and not specifically to its fiber component.

Scientific studies on fenugreek's effect on lactation are limited and often of low quality, with mixed results. Some small clinical trials suggest a possible increase in milk production, but these findings are not robust and often confounded by methodological issues. Importantly, there is little to no scientific evidence that fenugreek fiber (distinct from the seed or extract) specifically provides support for breast tissue health or any other aspect of the breast body system outside of lactation. Furthermore, there is no evidence that fenugreek fiber has any effect on breast size, shape, or overall breast health in non-lactating women.

In summary, the use of fenugreek (and, by extension, its fiber) to support the breast body system is primarily justified by traditional practices related to lactation, with minimal scientific backing and no evidence for other breast-related benefits.