Silk farmers often add supplements to mulberry leaves in the hope of producing more silk, but most tests use commercial hybrid silkworms and few checks whether faster-growing larvae actually spin more silk. We tested a commercial Aloe vera juice on Nistari, the indigenous silkworm race of Bangladesh. Mulberry leaves were dipped in juice diluted to 5, 10, 15, 20 or 25 mL per 100 mL of water and fed from the third larval stage until spinning, alongside untreated leaves, in 18 rearing trays of 60 larvae each (three trays per group). Nineteen traits of the larvae, cocoons, pupae and eggs were measured. Aloe vera changed the speed of growth rather than its end point: treated larvae gained 0.14 g more than untreated larvae between the first and fourth recording days and were 14% heavier on day 4, but the untreated larvae caught up, and final weight and total weight gain did not differ. Egg hatchability rose from 92.6% to 94.9% and was higher at every concentration. Cocoon shell weight and shell ratio, which determine how much silk is produced, did not change detectably, although the experiment could only detect changes of about 15% or more. Aloe vera juice therefore helped Nistari larvae grow faster and improved hatching, which matters for producing silkworm eggs, but did not increase silk. This fits the idea that a silkworm stops growing at a fixed body size, so extra nutrition shortens growth rather than enlarging the larva. Supplements should be judged by their effect on silk itself, not on larval weight alone.