If experienced strength athletes take 450 mg ursolic acid every day, they lose mainly body fat write Korean sports scientists in the Korean Journal of Physiology & Pharmacology. Although the researchers did not observe dramatic effects on muscle mass their subjects did gain significant amounts of strength.
Ursolic acid is found in herbs like rosemary, and also in apple peel. It’s a plant steroidlike compound that inhibits cancer cells [J Agric Food Chem. 2007 May 30;55(11):4366-70.] and animal studies have shown that it improves body composition: mice lose fat and gain muscle tissue if ursolic acid is added to their food. Other animal studies have shown that ursolic acid also extends endurance capacity.
So far there have been no human studies on the effects of ursolic acid, so the Koreans undertook some research. They used 16 subjects, all of whom had been doing strength training for at least three years, for their study. Seven of the subjects were given a placebo [RT] for eight weeks; nine were given ursolic acid [RT+UA].
The Koreans used an ursolic acid supplement manufactured by Labrada. They got the subjects to take three capsules a day, which provided them with a total of 450 mg ursolic acid. The subjects took one capsule at each mealtime.
All the subjects followed the same – pretty extensive – training schedule, six times a week.
Labrada did not sponsor the Korean study. The researchers were funded by the Korean government.
Ursolic acid supplementation resulted in a statistically significant reduction in fat mass, and a small, but not significant, increase in lean body mass.
The strength [better: torque] the subjects were able to develop in their right leg when they performed leg extensions and leg curls decreased a little in the placebo group. Strength increased significantly in the supplementation group.
Supplementation with ursolic acid boosted the concentration of IGF-1 and irisin. Irisin is a protein that muscle cells secrete when they are active. Oncologists believe that irisin helps explain why physical exercise protects against cancer.
The researchers had expected the supplementation would result in more muscle growth, and can’t explain why ursolic acid turned out to function more as a slimming aid that retained lean body mass. The Koreans do not express an opinion as to whether the supplement boosts the anti-carcinogenic effects of exercise.
“Our results show that an 8-week resistance training program with Ursolic Acid supplementation can decrease body fat percentage and increase IGF-1, irisin, and skeletal muscle strength without affecting muscle mass in men”, the researchers write. “Thus, this approach appears to be a promising strategy to improve skeletal muscle strength in men. However, the underlying molecular mechanisms involved in the increase of IGF-1, irisin, and muscle strength achieved through Ursolic Acid supplementation require further investigation.”
Ursolic Acid-induced elevation of serum irisin augments muscle strength during resistance training in men.
Ursolic acid (UA), a type of pentacyclic triterpenoid carboxylic acid purified from natural plants, can promote skeletal muscle development. We measured the effect of resistance training (RT) with/without UA on skeletal muscle development and related factors in men. Sixteen healthy male participants (age, 29.37±5.14 years; body mass index=27.13±2.16 kg/m(2)) were randomly assigned to RT (n=7) or RT with UA (RT+UA, n=9) groups. Both groups completed 8 weeks of intervention consisting of 5 sets of 26 exercises, with 10~15 repetitions at 60~80% of 1 repetition maximum and a 60~90-s rest interval between sets, performed 6 times/week. UA or placebo was orally ingested as 1 capsule 3 times/day for 8 weeks. The following factors were measured pre-and post-intervention: body composition, insulin, insulin-like growth factor-1 (IGF-1), irisin, and skeletal muscle strength. Body fat percentage was significantly decreased (p<0.001) in the RT+UA group, despite body weight, body mass index, lean body mass, glucose, and insulin levels remaining unchanged. IGF-1 and irisin were significantly increased compared with baseline levels in the RT+UA group (p<0.05). Maximal right and left extension (p<0.01), right flexion (p<0.05), and left flexion (p<0.001) were significantly increased compared with baseline levels in the RT+UA group. These findings suggest that UA-induced elevation of serum irisin may be useful as an agent for the enhancement of skeletal muscle strength during RT.
PMID: 25352765 [PubMed] PMCID: PMC4211129