The Claim

Supplementing feedlot steers with ractopamine hydrochloride (300 mg/day) or lubabegron (36 mg/day) for 35 days increases hot carcass weight by approximately 8–10% and longissimus muscle area by 10–12% compared to unsupplemented controls, without affecting dressing percentage, marbling score, subcutaneous fat depth, or meat color.

Source: The supplementation of lubabegron or ractopamine hydrochloride in the summer improved growth performance but did not impact rumination, mobility scores, and behaviors in feedlot cattle in the United States

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
20score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
1 study reviewed
In plain English

Feeding feedlot steers ractopamine hydrochloride or lubabegron for 35 days increases hot carcass weight by 8–10% and longissimus muscle area by 10–12% compared to steers not fed these supplements, with no change in dressing percentage, marbling, fat depth, or meat color.

See the scientific wording

Supplementing feedlot steers with ractopamine hydrochloride (300 mg/day) or lubabegron (36 mg/day) for 35 days increases hot carcass weight by approximately 8–10% and longissimus muscle area by 10–12% compared to unsupplemented controls, without affecting dressing percentage, marbling score, subcutaneous fat depth, or meat color, indicating enhanced lean tissue deposition without compromising carcass quality.

Why this might work

The supplement binds to receptors on muscle and fat cells, triggering a signal that tells muscle cells to build more protein and fat cells to stop storing fat. This redirects nutrients from fat to muscle, making the animal gain more lean muscle and less fat without changing how much it eats.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: The supplementation of lubabegron or ractopamine hydrochloride in the summer improved growth performance but did not impact rumination, mobility scores, and behaviors in feedlot cattle in the United States

    When cattle were given these two supplements for the last 35 days before slaughter, they grew more muscle and weighed more at slaughter, but their fat, marbling, and meat color stayed exactly the same as cattle not given the supplements.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.