Effects of Astragalus Membranaceus on Muscle Function (AD ASTRA)

Astragalus Membranaceus Modulates Inflammatory Markers Without Enhancing Muscle Function Following Intensified Resistance Training

This study evaluated whether daily supplementation with Astragali radix extract (480 mg/day) for 10 weeks could attenuate training-induced impairments in muscle function, joint pain, and inflammatory markers in moderately active young adults undergoing a structured resistance training program. Participants were randomized in a double-blind, placebo-controlled design to receive either Astragali radix extract (ASTRA) or placebo (PLA) during 8 weeks of progressive resistance training followed by 2 weeks of intensified training. The primary outcome was maximal voluntary isometric torque (MVIT) of the knee extensors. Secondary outcomes included one-repetition maximum (1RM) strength, knee range of motion, muscle soreness (VAS), and circulating blood biomarkers of muscle damage and inflammation.

Study Overview

• Status: Completed
• Conditions: Healthy Adult
• Intervention / Treatment: Dietary supplement: Astragalus Membranaceus; Dietary supplement: Placebo

Detailed Description

Background and Rationale Physical inactivity is associated with approximately 10% of premature deaths and an estimated €100 billion in annual healthcare costs. Current guidelines recommend at least 150 minutes of moderate-intensity aerobic activity per week alongside resistance training for optimal health. However, when the balance between training load and recovery is disturbed, athletes may develop non-functional overreaching (NFOR), a state of maladaptation characterized by adverse physiological, psychological, and functional outcomes requiring days to weeks for full resolution.

Astragali radix (Astragalus membranaceus), belonging to the Fabaceae family and officially included in the European Pharmacopoeia (8th ed.), is a traditional Chinese herbal medicine known for its antioxidant, anti-inflammatory, and immunomodulatory properties. Prior research has suggested potential benefits in reducing post-exercise inflammatory markers and improving aerobic performance, but its effects during prolonged, structured resistance training programs had not been systematically investigated.

Study Design This was a randomized, double-blind, placebo-controlled trial with 1:1 allocation. Twenty-four moderately active healthy young adults (mean age ~25 years; 13 males/11 females across groups) were enrolled after initial screening of 72 volunteers. Participants were randomly allocated to the ASTRA group (n=13) or PLA group (n=11). Randomization was performed using a computer-generated sequence.

Interventions Participants in the ASTRA group received 480 mg/day of Astragali radix hydroalcoholic extract (Axtragyl®, Giellepi S.p.A., Seregno, Italy; 2 capsules × 240 mg/day) for 10 weeks. The PLA group received matched capsules containing inert substances (microcrystalline cellulose, maltodextrin, magnesium salts of fatty acids) for the same period. Supplement compliance was monitored via daily text messages and collection of returned empty containers.

Training Protocol All participants performed a combined training intervention consisting of: (1) 8 weeks of regular resistance training (RT) at 3 sessions/week, with progressive overload targeting lower limb muscles (back squat, leg press, single-leg extension, single-leg curl, calf raises) at 70-80% of 1RM; followed by (2) 2 weeks of intensified training (IT) at 6 sessions/week, performing 10 sets of 1 repetition at 100% 1RM of leg press and leg extension. All sessions were supervised by experienced personnel.

Assessments

Testing was performed at three time points: baseline (BAS, one week before intervention), after 8 weeks of RT (48 hours post-last session), and after IT completion (24 hours post-last session). Assessments included:

Maximal voluntary isometric torque (MVIT) of knee extensors measured on a custom-built ergometer (primary outcome)

1RM of leg press and leg extension Knee range of motion (ROM) assessed by gyroscope-based goniometry during passive movement Muscle soreness via 100-mm visual analogue scale (VAS) Blood biomarkers: serum CPK, LDH, myoglobin, CRP, IL-6, TNF-α, IGF-1, cortisol, and testosterone (venous blood drawn at BAS, RT, and IT under standardized fasting conditions) Statistical Analysis A general linear model for repeated measures was used, with time (BAS, RT, IT) as within-subject factor and supplementation group (ASTRA vs. PLA) as between-subject factor. Post-hoc comparisons used Bonferroni correction. Effect sizes were reported as partial eta squared (η²). Statistical significance was set at p < 0.05.

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Pavia, Italy, 27100
    • Università di Pavia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Physical Activity Status: Moderately active, defined as a metabolic equivalent (MET) between 3 and 6 based on the International Physical Activity Questionnaire - Short Form (IPAQ-SF) (Bull et al., 2020).
• Health Status: Non-smokers and free from cardiovascular, metabolic, and neurological diseases.

Exclusion Criteria:

• Injuries: any muscular, bone, or joint injuries sustained within the 6 months prior to the study.
• Supplementation/Medication: A history of consuming dietary supplements or drugs within the 6 months preceding the intervention.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: PLACEBO	Dietary supplement: Placebo; Capsules containing an inert substance identical by visual, taste, and smell to the active formulation but without any active ingredients
Experimental: ASTRA	Dietary supplement: Astragalus Membranaceus; 480 mg daily of astragali radix extract for 10 weeks (2 capsules x day orally).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
MVIT	Maximal voluntary isometric torque	One week before the start of the intervention (BAS), 48 hours after RT phase, and 24 hours following the completion of IT phase.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ROM	Range of Motion	One week before the start of the intervention (BAS), 48 hours after RT phase, and 24 hours following the completion of IT phase
Muscle soreness	Subjects were asked to mark their pain level on the line under the supervision of the examiner while the knee joint was passively flexed and extended by the investigator.	One week before the start of the intervention (BAS), 48 hours after RT phase, and 24 hours following the completion of IT phase.
Serum Creatine Phosphokinase	Serum Creatine Phosphokinase	One week before the start of the intervention (BAS), 48 hours after RT phase, and 24 hours following the completion of IT phase.
Interleukin-6 (IL-6)	Interleukin-6 (IL-6)	One week before the start of the intervention (BAS), 48 hours after RT phase, and 24 hours following the completion of IT phase.
Tumor necrosis factor-alpha (TNF-α)	Tumor necrosis factor-alpha (TNF-α)	One week before the start of the intervention (BAS), 48 hours after RT phase, and 24 hours following the completion of IT phase.

Collaborators and Investigators

• Sponsor: University of Pavia

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2023
• Primary Completion (Actual): December 31, 2025
• Study Completion (Actual): February 25, 2026

Study Registration Dates

• First Submitted: April 20, 2026
• First Submitted That Met QC Criteria: April 20, 2026
• First Posted (Actual): April 27, 2026

Study Record Updates

• Last Update Posted (Actual): April 30, 2026
• Last Update Submitted That Met QC Criteria: April 26, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: inflammation; Dietary supplementation; muscle damage; force; non-functional overreaching
• Additional Relevant MeSH Terms: Pathologic Processes; Pathological Conditions, Signs and Symptoms; Inflammation; Huang Qi
• Other Study ID Numbers: UNIPV0040463/23

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No