Does phosphatidic acid (PA) build more muscle?

Short answer

No. It switched on a muscle-growth signal in cells, but PA alone meaningfully added muscle in just 1 human trial, a 28-person trial funded by the maker. Trials of 15 and 16 people and a review of 6 trials found no difference.

Does phosphatidic acid (PA) build more muscle?
'PA → muscle-growth switch on → more muscle' — does this formula hold?
PA is a substance that switches on a muscle-building signal (mTOR), and it is sold as a 750 mg daily supplement. We checked whether people who took it while training actually grew more muscle.
In cells, the switch did turn on
Soy PA raised the signal by 636%
When PA was added to muscle cells, the muscle-growth signal rose by 636% with soy PA and 221% with egg PA. The question is whether a signal switched on in cells turns into bigger muscles in people.
Just 1 trial, with 28 people, showed more muscle
2 kg more in 8 weeks, funded by the maker
When 28 people took 750 mg of PA during 8 weeks of training, lean mass (muscle and everything except fat) rose 2.4 kg, 1.2 kg more than the placebo group (1.2 kg). The PA maker funded this trial, and 2 of the authors were paid consultants to that company.
A 15-person trial measuring muscle thickness found no difference
All four spots on the thigh and upper arm
In a trial where 15 people took the same 750 mg for 8 weeks, changes in muscle thickness at four spots on the thigh and upper arm did not differ from placebo. Squat gains were 8.4% vs 8.1% and bench press 5.7% vs 5.1%, no difference. Both groups gained muscle and strength from training.
The other good-looking results were not thanks to PA
16 people: no statistical difference; 18 people: a mixed product
In a 16-person trial, lean mass rose 2.6% with PA and 0.1% with placebo, but the statistical test found no meaningful difference. In an 18-person trial, the product that added more muscle mixed PA with leucine, HMB and vitamin D.
What a review of 6 trials concluded
PA did not improve muscle or performance
A 2022 review of 6 trials published from 2012 to 2019 found that 3 showed no effect on muscle mass, and 1 of the trials that showed a benefit used a product mixed with other ingredients. The researchers concluded there is no basis for taking PA for muscle or performance.
Bottom line: PA did not build more muscle
The formula breaks at the 'cell signal → human muscle' link
In cells, PA raised the muscle-growth signal by 636%, but PA alone meaningfully added muscle in just 1 human trial, a 28-person trial funded by the maker. The 15- and 16-person trials and the 6-trial review found no difference. Taking PA does not grow more muscle than training alone.