Great North Run organisers have dropped a backer after discovering its business practices had been branded "unfair and deceptive" by American authorities.
The Great Run Company announced dietary supplement company Herbalife was their official nutrition partner last week.
But it has now said: "Having taken into account feedback, we have decided not to proceed with a partnership with Herbalife."
The supplement firm has been approached for comment.
The Newcastle to South Shields half marathon has had a number of sponsors and partners since it began in 1981.
Announcing the partnership with Herbalife, organisers said they were "delighted to welcome such an exciting and innovative brand on board".
But, last year, Herbalife was investigated by the US Federal Trade Commission (FTC) over whether it misled customers about the potential value of reselling its products.
In adverts, Herbalife suggested those who agreed to buy its products and become sales people could make a lot of money.
But, in July, the FTC said most "made little or no money" and some made losses.
"The incentives were to recruit more people who would then buy more product - whether or not there was a market to sell it," it said.
In July, the firm agreed to pay $200m (£150m) to settle the accusations.
The terms of the deal require Herbalife to reorganise its systems to reward retail sales more than recruitment.
In a statement made last year, the firm said it believed many of the FTC's allegations were "factually incorrect" but agreed to the settlement to avoid the "financial cost and distraction of protracted litigation".