How do you raise your follistatin levels for more muscle and bone building?
Strength training three times a week demonstrably raises your follistatin levels, and adequate protein intake or essential amino acids strengthen that effect even further.
Follistatin is a protein that holds back myostatin, a substance that slows muscle growth. A higher follistatin-to-myostatin ratio is beneficial for muscle mass and bone building. Strength training is the most reliable way to raise follistatin: training three times a week for twelve weeks already produced a clear rise in healthy women aged 65 and older.
Combining strength training with essential amino acids (5.5 grams, twice a day) works better than training alone. The follistatin-to-myostatin ratio rose the most in the combination group, and muscle mass increased measurably. Essential amino acids without training showed no demonstrable effect on follistatin on their own. Similar results appear in people with sarcopenia (too little muscle mass due to ageing): combining strength training with at least 15 grams of protein per day, mainly from dairy, raised follistatin and lowered myostatin at the same time, while muscle strength and lean body mass increased.
Intensive functional training (a high-intensity circuit of strength exercises) also raised follistatin in men with obesity. Spinach thylakoid supplements were studied in a small exploratory group as an addition to that training. There was a trend towards an extra effect on follistatin, but it was not strong enough to be conclusive and is certainly not yet proven.
An added benefit of combining strength training with essential amino acids: markers of inflammation such as IL-6 and certain stress hormones dropped noticeably. This points to broader health gains, beyond muscle mass alone.
This answer is based on three studies in which participants were randomly assigned to groups, one of which brings together seven earlier studies of the same kind. The participant numbers are limited (fifteen to twenty per group in the smallest study), which means the findings on spinach thylakoids and the study in men with obesity are too early for firm conclusions. The findings in older women and people with sarcopenia are more consistent and come from several independent studies, which makes them more robust. The researchers behind the combined summary themselves pointed to the wide variation in duration and design of the underlying studies as a limitation.