Taking omega-3 fatty acids, citrulline, or collagen supplements does not lead to larger muscles in people who lift weights, but these supplements might help with how well the body handles training,...

We analyzed the available evidence and found that omega-3, citrulline, and collagen supplements do not lead to larger muscles in people who lift weights [1]. The evidence we’ve reviewed so far leans toward the idea that these supplements may help the body handle training better, recover more effectively, or support connective tissues like tendons and ligaments — but not by increasing muscle size directly [1]. We looked at two assertions related to this question, and both point to the same conclusion: while these supplements might improve how your body responds to resistance training, they don’t appear to make muscles grow bigger on their own. Omega-3s are fats that can reduce inflammation, citrulline may help with blood flow during workouts, and collagen provides building blocks for connective tissues — but none of these mechanisms have been shown in the evidence we reviewed to result in greater muscle mass in trained adults. There’s no data suggesting these supplements cause muscle loss or harm, but there’s also no clear signal that they add size beyond what training alone provides. The current evidence doesn’t show a direct link between taking these supplements and gaining more muscle, even though they might make training feel easier or recovery smoother. If you’re already lifting weights regularly, these supplements might help you feel less sore or keep your joints moving well — but don’t expect them to make your muscles bigger. Focus on your training, protein intake, and rest first.