Oral tracers detect changes in muscle protein production
A laboratory experiment tested protein synthesis measurements during feeding and exercise, without assessing lasting muscle growth.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
Oral amino acid tracers detected greater muscle protein production after feeding, with or without prior resistance exercise, compared with resting while fasted. This supports detecting short-term changes under the tested conditions. It does not establish lasting muscle growth or benefits from a particular training or supplement routine.
The abstract omits sample size and leaves its correlation statement incomplete. This abstract-based summary cannot establish full agreement between the tracer methods.
What researchers found
Myofibrillar protein synthesis with leucine tracer
Exercise plus feeding versus rest and fasting over 300 minutes; group averages ± standard deviation (variation between participants), p < 0.01. %/h means the percentage of measured muscle protein newly made per hour, not muscle-mass growth.
Following the tracers
Researchers tracked swallowed tracers using blood samples and muscle biopsies. Fed participants received a carbohydrate and amino acid drink at rest or after exercise; fasting participants received tracers alone.
Detection differs from agreement
Both tracer approaches distinguished fed conditions from fasting. That supports detecting changes in these laboratory conditions, but does not show that their estimates can be used interchangeably.
The original publication
Oral amino acid tracer delivery detects feeding and exercise changes in myofibrillar protein synthesis rates in male adults.
Mazzulla M, Hodson N, Scaife PJ et al.
Physiol Rep · 2026
- PubMed ID
- 41776771
- Record checked
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