Published in the Journal of the International Society of Sports Nutrition in 2019
Background:
Shilajit is a natural exudate commonly used in Ayurvedic medicine, composed of fulvic acids, dibenzo-α-pyrones, proteins, and minerals. It has been traditionally utilized for its potential to enhance physical performance and promote overall health. Previous research has indicated that Shilajit may improve mitochondrial function, increase testosterone levels, and upregulate extracellular matrix-related gene expression, which could contribute to muscle strength and connective tissue integrity.
Objective:
The primary aim of this study was to investigate the effects of 8 weeks of Shilajit supplementation at two different dosages—250 mg per day (low dose) and 500 mg per day (high dose)—compared to a placebo on:
- Maximal Voluntary Isometric Contraction (MVIC) Strength: A measure of the maximum force that a muscle group can exert without movement.
- Concentric Peak Torque: The highest rotational force produced during muscle shortening.
- Fatigue-Induced Percent Decline in Strength: The reduction in muscle strength following a fatiguing exercise protocol.
- Serum Hydroxyproline (HYP) Levels: An indirect biomarker of collagen degradation, indicating connective tissue integrity.
Methodology:
- Participants: Sixty-three recreationally active men, averaging 21.2 years in age, were randomly assigned to one of three groups:
- High dose Shilajit (500 mg/day)
- Low dose Shilajit (250 mg/day)
- Placebo
- Study Design: This was a double-blind, placebo-controlled study conducted over eight weeks.
- Testing Procedures:
- Pre-Supplementation Testing: Participants performed two pretest MVICs, followed by two sets of 50 maximal, bilateral, concentric isokinetic leg extensions at 180°/s, separated by 2 minutes of rest, and then two posttest MVICs.
- Post-Supplementation Testing: After eight weeks of supplementation, participants repeated the same testing procedures.
- Blood Analysis: Serum hydroxyproline levels were measured to assess collagen degradation.
- Data Analysis: Participants were further divided into upper and lower 50th percentiles based on pre-supplementation MVIC and baseline HYP levels to assess the effects in different subgroups.
Results:
- Fatigue-Induced Decline in MVIC:
- In the upper 50th percentile group, the high dose Shilajit group exhibited a significantly smaller decline in MVIC strength post-supplementation (8.9%) compared to the low dose (17.0%) and placebo (16.0%) groups.
- No significant difference was observed between the low dose and placebo groups.
- Serum Hydroxyproline Levels:
- For participants in the upper 50th percentile, the high dose group had significantly lower post-supplementation HYP levels (1.5 μg/mL) compared to both the low dose (2.4 μg/mL) and placebo (2.4 μg/mL) groups.
- This suggests reduced collagen degradation in the high dose group.
Conclusions:
The study concluded that eight weeks of supplementation with 500 mg/day of PrimaVie® Shilajit:
- Attenuated Fatigue-Induced Declines in Muscle Strength: Participants maintained greater muscular strength following a fatiguing protocol.
- Reduced Serum Hydroxyproline Levels: Indicating decreased collagen degradation and potentially enhanced connective tissue integrity.
These findings suggest that a higher dose of Shilajit supplementation may promote favorable muscle and connective tissue adaptations, particularly in individuals with higher baseline strength levels.
Key Information:
- Shilajit Composition: Contains fulvic acids, dibenzo-α-pyrones, proteins, and minerals.
- Dosage: The study compared 250 mg/day and 500 mg/day dosages.
- Duration: 8-week supplementation period.
- Participants: Recreationally active men, average age 21.2 years.
- Outcomes Measured:
- MVIC strength
- Concentric peak torque
- Fatigue-induced percent decline in strength
- Serum hydroxyproline levels
- Significant Findings:
- 500 mg/day Shilajit supplementation reduced fatigue-induced declines in muscle strength.
- Lowered serum hydroxyproline levels, indicating reduced collagen degradation.
- Implications: High-dose Shilajit supplementation may enhance muscle performance and support connective tissue health in active individuals.
These insights provide a comprehensive understanding of the study’s design, findings, and implications for the use of Shilajit as a dietary supplement to support muscle and connective tissue health.