Krill oil helps to preserve muscle mass and strength during weight loss

Research reveals that krill oil supplementation combined with an alternate-day fasting diet helps to reduce the decline of fat-free (mainly muscle) mass and muscle strength, which is commonly associated with losing weight. The authors note the study is the “first of its kind” to explore krill oil’s effects on muscle mass and strength during diet-induced weight loss. It used krill oil supplements supplied by Aker BioMarine.

A global growing interest in weight management solutions has also illuminated potential adverse health implications of rapid weight loss, such as loss of skeletal muscle. This can negatively impact metabolic health, physical function, and long-term weight maintenance. 

The study, led by the University of Glasgow, UK, did not include participants on medications like GLP-1 receptor agonists. However, its authors say their findings provide insights for various weight loss scenarios. 

“While losing weight is often a good thing, one of the unintended consequences is that we don’t only lose fat, but we also lose muscle. In this study, we have found that krill oil can help preserve our muscle mass and strength as we lose weight,” says study co-author Dr. Stuart Gray, professor at the University of Glasgow. 

“As maintenance of muscle is very important for our overall health and quality of life, these are extremely exciting findings.” 

Study setup

The scientists hypothesized that the long-chain omega-3 polyunsaturated fatty acids in krill oil could minimize declining muscle mass and muscle strength. 

The eight-week, double-blind, randomized, placebo-controlled trial, published in Obesity, included 41 participants aged 25–65 with an above-average body mass index.

Participants consumed four capsules daily before and during weight loss, containing either four grams of Superba Boost krill oil or vegetable oil (for the placebo group). Each Superba Boost krill oil capsule contained 191 mg eicosapentaenoic acids (EPA), 94 mg docosahexaenoic acids (DHA), 78 mg choline, and 100 mcg astaxanthin. 

At Natural Products Expo West 2025, we discussed krill oil’s benefits in sports nutrition with Aker BioMarine’s CEO, Matts Johansen.During fasting days, participants consumed less than 500 kcal in a two-hour eating window. On regular eating days, participants could eat normally but were told to avoid overeating. 

Muscle health benefits

The researchers measured body mass, fat-free mass, handgrip strength, chair rising, and fatty acid composition before and after the intervention. 

Compared to the placebo group, participants consuming krill oil lost less muscle mass and handgrip strength. They also took less time to rise out of a chair. 

Moreover, the research found a greater reduction in systolic blood pressure in the krill group than in the placebo group. The krill oil group also showed a higher omega-3 index, EPA, and DHA. 

Due to its impact on muscle mass and strength, the researchers state that consuming four grams of krill oil daily is a “viable strategy” to mitigate adverse effects associated with rapid weight loss. They recommend future studies to explore the underlying mechanisms of krill oil’s impact on muscle function preservation. 

“We are pleased to continue our work with the University of Glasgow to explore further krill oil and its positive effects on muscle mass and function,” says Line Johnsen, SVP Human Health Ingredients R&D at Aker BioMarine. 

“We have previously conducted scientific studies with Dr. Gray and his team to show how the important nutrients found in krill impact muscle strength and mass with age, and this follow-up study helps strengthen our understanding of this area.”

At the same time, Aker BioMarine also calls for new omega-3 sources to keep up with growing demand among health-conscious consumers. Fish oil cannot keep up with demand, and krill trawling is linked to severe negative environmental impacts. Last month, Nutrition Insight discussed the company’s strategies for balancing ocean health and global nutrition demands with its CEO, Matts Johansen.