An ad for Horlicks in Bengali, broadcast in the UK by a Nepali TV channel, has been banned by the Advertising Standards Authority.
The ad featured a challenge which showed two different groups of children, one which was given Horlicks, and one which was not.
The ad depicted experts claiming the children given the malt drink became "taller, stronger and sharper".
The ASA said: "Because we had seen no evidence to substantiate the claims, we considered that the ad was misleading and that Nepali TV should not have broadcast it in the UK."
Horlicks' parent company, GlaxoSmithKline, said the ad had been broadcast on Nepali TV without their consent as part of a re-broadcast deal organised with a broadcaster in Bangladesh.
It added that the claims were true for children in that part of the world and were supported by clinical studies undertaken by the National Institute of Nutrition in India.
Nepali TV failed to respond to the ASA, but has withdrawn the ad.