Leucine, Omega-3, and Resistance Training for Sarcopenia

For older adults with clinically diagnosed sarcopenia, the most useful supplement finding comes with a condition: leucine-enriched amino acids help most when they accompany resistance training. Leucine on its own, even at 6 to 7.5 g per day, has not reliably improved grip strength or muscle mass. Omega-3 supplements also show benefits when paired with resistance exercise, but the best omega-3 evidence comes from general older-adult populations rather than people diagnosed with sarcopenia.

That leaves a practical hierarchy. Resistance training is the treatment foundation. Leucine-enriched essential amino acid formulations have the more population-specific evidence as an add-on for diagnosed sarcopenia. Omega-3 is a reasonable secondary adjunct, but no adequately powered head-to-head trial has established that it beats—or loses to—leucine-based nutrition in this population.

Resistance training does the heavy lifting

Supplements do not replace progressive resistance training. A 2022 meta-analysis by Wang et al. included 23 randomized trials with 1,252 older adults with sarcopenia. Exercise improved grip strength by 2.38 kg (95% CI, 1.33 to 3.43), lower-extremity muscle mass by 0.28 units (95% CI, 0.01 to 0.56), walking speed (SMD 0.88; 95% CI, 0.49 to 1.27), and functional mobility. The analysis covered exercise interventions rather than resistance training alone, but it establishes that training changes the outcomes sarcopenia is defined by.

A 2023 network meta-analysis by Zeng et al., covering 20 studies and 1,347 older adults with sarcopenia, found that resistance training improved handgrip strength and Timed Up and Go performance versus control and other interventions. In older women with sarcopenia, a 2026 meta-analysis by Zhou et al. found significant improvements in handgrip strength (SMD 0.43; 95% CI, 0.11 to 0.74), gait speed (SMD 0.37; 95% CI, 0.09 to 0.64), and knee-extension strength (SMD 0.85; 95% CI, 0.37 to 1.33).

Those results matter more than any supplement ranking. If someone must choose between training and a tub of leucine powder, the dumbbells have the better case.

Why leucine looks useful only alongside training

The strongest amino-acid evidence concerns combined interventions, not leucine in isolation. A 2026 systematic review and meta-analysis by Xie et al. focused on adults age 65 or older with sarcopenia defined by EWGSOP or equivalent criteria. It evaluated resistance training plus amino acid-based supplementation against resistance training alone, using handgrip strength, gait speed, and skeletal muscle index as primary outcomes. The review used ROB 2 and GRADE methods, although it also allowed some self-defined sarcopenia criteria, which adds heterogeneity.

Its most distinctive finding was mechanistic rather than a direct functional endpoint: essential amino acids stimulated muscle protein synthesis about 50% more than whey protein in sarcopenic patients. Muscle protein synthesis is a useful biological signal, but it is not the same as gaining enough muscle or strength to change daily function. Still, it gives a plausible reason that amino-acid composition may matter beyond total protein intake.

The more focused 2025 leucine meta-analysis by Huang et al. included only older adults with EWGSOP2-defined sarcopenia. Within its constituent studies, Park et al. reported that grip strength rose by 0.796 kg for each 1 g/day increase in leucine dose across studies. That is a dose-response observation across trials, not proof that raising an individual's dose will produce the same gain.

More clinically relevant, Mori et al. studied 81 adults with sarcopenia and compared leucine-enriched whey plus resistance training with resistance training alone. At 24 weeks, the combined group had significantly greater handgrip strength and appendicular skeletal muscle index. The supplied report does not provide the effect sizes or confidence intervals, so they should not be guessed at. The direction and the comparison are clear: adding leucine-enriched whey to training outperformed training alone on those measures.

Other reviews point in the same direction. A 2025 meta-analysis by Li et al. found that BCAA-rich supplements combined with resistance training improved body composition and physical function versus training alone in older patients with sarcopenia. A 2023 review by Chang et al. found synergistic effects when leucine was combined with whey protein and vitamin D. These are not interchangeable products: leucine alone, leucine-enriched whey, BCAA mixtures, essential amino acids, and vitamin D-containing formulas have different compositions and trial designs.

The leucine-only trials set the boundary

The same Huang meta-analysis contains the evidence that should keep leucine marketing in check. In the LACE trial, sarcopenic adults took 7.5 g/day of leucine—2.5 g three times daily—without standardized concurrent resistance training. Compared with placebo, leucine did not significantly improve the Short Physical Performance Battery, grip strength, gait speed, or chair-stand time.

Martínez-Arnau et al. tested 6 g/day for 13 weeks in sarcopenic adults. Participants improved walking time, but they did not show significant improvements in handgrip strength or skeletal muscle index. These were not low-dose failures. They were high-dose leucine trials that did not move the two outcomes most central to sarcopenia diagnosis.

The intervention supported by the evidence is leucine-enriched amino acids plus resistance training—not leucine as a substitute for training.

The contrast between the Mori trial and the LACE and Martínez-Arnau trials does not prove that training is the only reason results differed; formulations, participants, and protocols also varied. But it does make the simple story—more leucine equals more muscle—untenable. Training is the consistent dividing line in the evidence presented here.

Omega-3 has a real signal, but in a different population

Omega-3 should not be dismissed. A 2022 meta-analysis by Cornish et al. pooled 16 studies involving 2,438 older adults, with a mean age of 69.1 years. Eight studies included resistance exercise training. Across varied omega-3 sources—fish oil, krill oil, flaxseed, and Calanus oil—supplementation improved lean tissue mass and lower-body strength, with better effects when paired with resistance exercise.

Yet those results cannot be numerically ranked against the leucine evidence as though both analyses sampled the same condition. Cornish et al. enrolled general older adults with varied health profiles, not an EWGSOP2-diagnosed sarcopenia cohort. The preparations and doses also varied enough that the review cannot establish a reliable omega-3 dose-response for sarcopenia.

A single 2022 randomized trial of krill oil by Alkhedhairi et al. found improved skeletal-muscle function and size in older adults. It strengthens the case that at least one omega-3 preparation can affect muscle-related outcomes. It does not answer whether krill oil works as well in people with diagnosed sarcopenia, or whether it adds more than leucine-enriched amino acids during the same training program.

The trial designed to answer the comparison cannot rank treatments yet

The ENHANce trial had the right structure: community-dwelling older adults with EWGSOP2-defined sarcopenia were assigned across five arms—control, exercise alone, protein alone, exercise plus protein, or exercise plus protein plus omega-3. It enrolled 58 participants and explicitly tested feasibility, not treatment efficacy.

Its design also excluded people consuming more than 1.5 g of protein per kilogram of body weight per day. That makes the cohort relatively protein-insufficient at baseline and limits generalization to protein-replete adults with sarcopenia. A future adequately powered version could test whether omega-3 adds value after training and protein are already in place. This pilot cannot provide a credible efficacy ranking.

What to do with the evidence now

• Make resistance training the core intervention. The evidence consistently links it to improvements in strength, muscle measures, and physical performance in sarcopenia.
• Consider a leucine-enriched essential amino acid or protein formulation as a training adjunct. The best sarcopenia-specific evidence supports combined use, and multi-ingredient formulas that include whey and vitamin D may perform differently from leucine alone.
• Do not expect 6 to 7.5 g/day of leucine alone to fix sarcopenia. The LACE and Martínez-Arnau results did not show significant grip-strength or muscle-index benefits without standardized training.
• View omega-3 as an optional secondary addition, not a proven replacement for amino-acid support. Its exercise-paired signal in older adults is credible, but equivalent evidence in formally diagnosed sarcopenia is missing.

Older adults with sarcopenia also need individualized clinical assessment: kidney disease, swallowing problems, malnutrition, medications, fracture risk, and current dietary protein intake can all change the appropriate plan. The current evidence favors a sequence—train first, then consider leucine-enriched nutrition, with omega-3 as a possible addition—not a winner-take-all supplement contest.