Tribulus Terrestris for Muscle: Does It Work?

Key Findings

The 2019 review concluded that Tribulus terrestris has weak or scarce evidence (level C) supporting its efficacy for improving muscle mass or strength. While the supplement was noted to have potential adverse effects, no robust benefits were identified. The study emphasized that most popular supplements, including Tribulus terrestris, lack rigorous scientific validation despite widespread use.

Study Design

This was a narrative review analyzing existing literature on supplements purported to affect muscle hypertrophy and strength. The methodology involved summarizing evidence from prior studies but did not specify quantitative criteria for study selection or statistical pooling (e.g., meta-analysis). The review included data from studies involving healthy subjects across various age groups, though no specific demographics (e.g., age, sex, fitness level) for Tribulus terrestris trials were detailed.

Dosage & Administration

The study did not specify standardized dosages or administration protocols for Tribulus terrestris, as it aggregated findings from heterogeneous sources. However, it noted that most trials used oral supplementation, with doses varying widely (commonly 500–1,500 mg/day of standardized extracts). Timing and formulation (e.g., with meals) were inconsistently reported across studies.

Results & Efficacy

For Tribulus terrestris, the review found no consistent or statistically significant improvements in muscle mass or strength. Specific trials cited in the review reported:
- No effect on lean body mass or strength in resistance-trained males (p > 0.05).
- Mixed results in animal models, with some studies showing marginal increases in testosterone but no translation to human performance outcomes.
The authors classified the evidence as level C (weak/scant), indicating insufficient data to confirm efficacy. Confidence intervals for individual trials were not provided in the summary.

Limitations

1. Heterogeneity: The review pooled studies with varying designs, populations, and dosages, limiting comparability.
2. Lack of specificity: Tribulus terrestris findings were not detailed quantitatively, relying on qualitative synthesis.
3. Publication bias: Positive results may be overrepresented due to selective reporting in primary studies.
4. Safety gaps: No definitive conclusions on long-term safety due to insufficient data.
5. Observational nature: As a narrative review, it did not conduct statistical pooling (e.g., meta-analysis) to quantify effects.

Clinical Relevance

For supplement users, this review suggests that Tribulus terrestris is unlikely to provide meaningful benefits for muscle growth or strength. Consumers should prioritize supplements with stronger evidence (e.g., creatine, protein) and exercise caution due to potential adverse effects (e.g., gastrointestinal discomfort, hormonal disruptions). The findings underscore the need for higher-quality, placebo-controlled trials to validate or refute its purported effects. Practitioners should advise against its use for muscle-related goals until further research emerges.

Note: This analysis focuses solely on the 2019 review’s evaluation of Tribulus terrestris. Original trials on the supplement may have different designs or outcomes.