At least, that's what some researchers are claiming in a paper that's due to be published soon.
Here's a link to the research:
Of note, ergo-log, in their write-up, include the following note: "Wall and his colleagues have been working closely with Quorn's producer for years, who by the way sponsors their research." Which is not to say the findings are false, but it's worth bearing in mind who's paying for the findings.
Here's a link to their assessment:
A study has found that mycoprotein, the protein-rich food source that is unique to Quorn products, stimulates post-exercise muscle building to a greater extent than milk protein.
The results showed that while those who ingested milk protein increased their muscle growth rates by up to 60%, those who had mycoprotein increased their muscle growth rates (MGRs) by more than 120% -- showing that mycoprotein, the main ingredient in all Quorn products, is a more effective source of protein to promote muscle growth.
The results showed that while those who ingested milk protein increased their muscle growth rates by up to 60%, those who had mycoprotein increased their muscle growth rates (MGRs) by more than 120% -- showing that mycoprotein, the main ingredient in all Quorn products, is a more effective source of protein to promote muscle growth.
Here's a link to the research:

Quorn protein builds muscle better than milk protein
A study has found that mycoprotein, the protein-rich food source that is unique to Quorn products, stimulates post-exercise muscle building to a greater extent than milk protein.
www.sciencedaily.com
Of note, ergo-log, in their write-up, include the following note: "Wall and his colleagues have been working closely with Quorn's producer for years, who by the way sponsors their research." Which is not to say the findings are false, but it's worth bearing in mind who's paying for the findings.
Here's a link to their assessment:
Is Quorn a better muscle builder than milk protein?
For young men lifting weights, meat substitute Quorn is a better muscle builder than old-fashioned milk protein. At least, that's what researchers at the University of Exeter in England claim.
ergo-log.com