The reality TV personality was due to join TOWIE colleagues James 'Arg' Argent, Billi Mucklow and Cara Kilbey in the 26-mile race on April 22.
However, it has been alleged that Goodger gave up after just a day of training, which reportedly saw her collapse in tears during a two-mile run.
The 25-year-old, who was shown crying over her physique in the latest series of TOWIE, is quoted as telling the Daily Star: "I just couldn't be bothered with it."
A family friend added: "She hates working out and she just didn't put in any effort to get race-ready. She couldn't even get through a two-mile jog at bootcamp without sobbing that it was too tough.
"She would have embarrassed herself if she had started the race. There is no way she would have made it through 26 miles."
A spokesperson for Goodger confirmed: "Unfortunately her trainer has advised against her running the marathon for this year, and she will concentrate on doing it next year."
Fans can donate to Mucklow and Kilbey, who are competing in support of Samaritans, via their Virgin Money Giving page.
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