What is ursolic acid and does it help preserve muscle?

This entry is part of the Nutri Tailor Health Reference Library — cited research on supplements, nutrients and adjacent areas of health.

Summary

Ursolic acid is a plant triterpenoid found in apple peel, rosemary and basil, researched for muscle preservation and body composition. The strongest evidence is preclinical, where mouse studies showed less muscle wasting and more muscle growth. Human trials are small and split. An 8 week trial in 16 men found greater strength gains alongside resistance training, while a 2021 trial at 400 mg a day found no added strength or muscle in trained men already eating high protein. A 2024 pooled analysis across six trials found no significant change in body weight or composition. A defined 8 to 12 week self trial is the honest way to find out whether the mechanism does anything for you.

How it works

Ursolic acid was identified through gene expression screening of human muscle atrophy as a compound whose signature opposes muscle wasting, and in mice it increased muscle mass and brown fat activity while improving insulin sensitivity. Whether these mechanisms translate to meaningful effects in humans at achievable oral doses is the open question, partly because oral bioavailability of ursolic acid is low.

Effective dose

Human trials have used 400 to 450 mg a day, usually split across meals. The positive strength finding came from an 8 week resistance training trial in 16 men, while an 8 week trial at 400 mg a day in trained men eating around 1.6 g of protein per kg found no added strength or muscle gain. There is no established effective dose because effectiveness itself is not yet established in humans. If you run a self trial, 400 to 480 mg a day for 8 to 12 weeks alongside consistent training is the pattern the research used.

Forms compared

Ursolic acid is sold as extracts from rosemary leaf or apple peel, standardised to a stated ursolic acid content. The compound is identical regardless of botanical source, so the standardised milligram content matters more than the plant it came from. It is fat soluble, which is why research protocols take it with food.

Timing

Take with meals that contain some fat, split across the day. The trials dosed two or three times daily. Consistency across 8 to 12 weeks matters more than clock time, because any effect on body composition is slow and cumulative.

Safety profile

Short term human trials at 400 to 450 mg a day reported no significant adverse effects. Long term safety data beyond a few months does not exist, which argues for defined trial windows rather than indefinite open ended use.

Special populations

Not studied in pregnancy or breastfeeding, so avoid in both. Trials have covered young trained men, resistance trained men and postmenopausal women. The postmenopausal trial found improved handgrip strength alongside exercise but no change in metabolic syndrome components. Older adults losing muscle are the population the preclinical work points at, and the group with the least direct trial evidence.

Interactions

No established interactions with prescribed drugs at supplemental doses, though formal interaction studies are lacking. If you take prescribed drugs, check any new supplement with your GP or pharmacist first. Dietary fat improves absorption of fat soluble compounds and that applies here.

Guideline positions

No UK or EU authority sets an intake reference for ursolic acid and no NRV exists. NHS guidance does not cover the compound. The evidence anchors are the preclinical mouse work that started the field, two small resistance training trials with opposite results, and a 2024 pooled analysis finding no significant change in body weight or composition across six trials.

Practical framework

Ursolic acid suits a defined self trial rather than open ended use. A sensible pattern is 8 to 12 weeks at 400 to 480 mg a day with food, alongside consistent resistance training, judged on strength numbers and how you feel. If your protein intake is already high, the best controlled trial suggests you may see nothing extra, and that is worth knowing before you spend. Nutri Tailor stocks UK made ursolic acid capsules providing 80 mg per capsule from rosemary leaf extract, dosed at 2 capsules three times daily with meals for 480 mg a day, at nutritailor.co.uk/products/ursolic-acid.

Common misconceptions

The strongest claims about ursolic acid come from mouse studies, and the leap from mouse to human has not held cleanly. It is marketed as an apple peel anabolic, yet the best controlled human trial found nothing extra once protein was adequate. A positive small trial also exists, so the honest position is unresolved rather than debunked. It is not a substitute for training or protein, the two levers with far stronger evidence for muscle preservation.

Sources

Bang HS, Seo DY, Chung YM, et al. 2014. Ursolic Acid-induced elevation of serum irisin augments muscle strength during resistance training in men. Korean Journal of Physiology and Pharmacology.
Lobo PCB, Vieira IP, Pichard C, et al. 2021. Ursolic acid has no additional effect on muscle strength and mass in active men undergoing a high-protein diet and resistance training. Clinical Nutrition (Elsevier).
Systematic review team, Taylor and Francis publication 2024. The effects of ursolic acid on cardiometabolic risk factors: a systematic review and meta-analysis. PMC / Taylor and Francis.
Crisp AH, et al. 2021. No additional effects of ursolic acid supplementation associated with combined exercise program on metabolic syndrome of postmenopausal women. Clinical Nutrition ESPEN.

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