Here are some known legal and safe supplements that are commonly used to boost testosterone levels and/or promote muscle growth:

1. Creatine Monohydrate: Creatine is one of the most researched and effective supplements for increasing muscle mass and enhancing performance in high-intensity exercise. It is safe and well-tolerated for both short-term and long-term use¹. Creatine works by increasing the phosphocreatine stores in muscles, allowing for increased ATP production during high-intensity activities².

2. Protein Supplements: Protein is essential for muscle growth and repair. Whey protein, casein, and plant-based protein powders are popular options for increasing dietary protein intake, which is crucial for muscle hypertrophy³.

3. Branched-Chain Amino Acids (BCAAs): BCAAs, including leucine, isoleucine, and valine, are vital for muscle protein synthesis and reducing muscle breakdown during exercise. They can be taken as a supplement to support muscle growth and recovery⁴.

4. Beta-Alanine: This amino acid helps buffer acid in muscles, increasing exercise capacity and muscle endurance during high-intensity workouts. It is safe and effective for improving athletic performance⁵.

5. D-Aspartic Acid: Some studies suggest that D-Aspartic Acid may help increase testosterone levels in men, although more research is needed to confirm its efficacy. It is considered safe when used appropriately⁶.

It's essential to note that while many "testosterone boosters" are marketed, not all have substantial scientific backing to support their claims. Some may contain ingredients that are not effective or even harmful⁷.

Footnotes

1. Matthew Hall et al, "Creatine Supplementation: An Update," PubMed, 2021. ↩

2. Shih-Hao Wu, "Creatine Supplementation for Muscle Growth: A Scoping Review of Randomized Clinical Trials from 2012 to 2021," NCBI, 2022. ↩

3. Massimiliano Mazzilli, "The Use of Dietary Supplements in Fitness Practitioners: A Cross-Sectional Observation Study," NCBI, 2021. ↩

4. "Office of Dietary Supplements - Dietary Supplements for Exercise and Athletic Performance," ODS, 2024. ↩

5. Chase G. Clemesha, "‘Testosterone Boosting’ Supplements Composition and Claims," NCBI, 2019. ↩

6. Adithya Balasubramanian et al, "Testosterone Imposters: An Analysis of Popular Online Testosterone Boosting Supplements," NCBI, 2024. ↩

7. Chase G. Clemesha, "‘Testosterone Boosting’ Supplements Composition and Claims Are not Supported by the Academic Literature," NCBI, 2019. ↩

Beta-ecdysterone, also known as ecdysterone, is a phytosteroid that has been gaining attention for its potential effects on muscle growth and performance enhancement. Here is what the research says about beta-ecdysterone:

1. Anabolic Effects: Studies have shown that ecdysterone can exhibit a strong hypertrophic effect on muscle fibers. For instance, in a study conducted on rats, ecdysterone was found to increase muscle fiber size significantly, even more so than some well-known anabolic steroids like metandienone and trenbolone¹. In humans, a 10-week study involving strength training demonstrated significant increases in muscle mass and strength in participants taking ecdysterone compared to a placebo².

2. Mechanism of Action: The anabolic effects of ecdysterone are believed to be mediated through the estrogen receptor beta (ERβ). It has been shown to transactivate a reporter gene in HEK293 cells, indicating an ERβ-mediated mechanism³. This mechanism suggests that ecdysterone may enhance muscle protein synthesis, leading to muscle growth⁴.

3. Safety and Efficacy: Research has not only focused on the anabolic potential but also on the safety of ecdysterone. No significant increases in biomarkers for liver or kidney toxicity were observed in studies, suggesting that ecdysterone is safe for use at the dosages tested². Additionally, ecdysterone has been found to enhance physical performance without the androgenic side effects associated with anabolic steroids⁵.

4. Potential Inclusion in Prohibited Lists: Due to its potent anabolic effects, there have been discussions about including ecdysterone in the list of prohibited substances by the World Anti-Doping Agency (WADA) under the category of "other anabolic agents"⁶.

5. Mixed Results in Different Studies: While some studies have demonstrated significant anabolic effects, others have shown no significant impact on muscle mass or training adaptations, especially in resistance-trained males⁷. This indicates that the efficacy of ecdysterone might depend on factors such as the subject's training status, dosage, and the form of administration.

Overall, beta-ecdysterone shows promise as a supplement for muscle growth and performance enhancement. However, more extensive and consistent findings in human studies are needed to fully validate its efficacy and safety.

Footnotes

1. MK Parr, "Ecdysteroids: A novel class of anabolic agents?", PubMed Central, 2015. ↩

2. Eduard Isenmann, "Ecdysteroids as non-conventional anabolic agent: performance enhancement by ecdysterone supplementation in humans," PubMed, 2023. ↩ ↩²

3. Maria Kristina Parr, "Estrogen receptor beta is involved in skeletal muscle hypertrophy induced by the phytoecdysteroid ecdysterone," PubMed, 2014. ↩

4. Gabriella Ambrosio, "Urinary Elimination of Ecdysterone and Its Metabolites Following a Single-Dose Administration in Humans," PubMed Central, 2021. ↩

5. Silvia Pérez-Piñero, "A 12-Week Randomized Double-Blind Placebo-Controlled Clinical Trial, Evaluating the Effect of Supplementation with a Spinach Extract on Skeletal Muscle Fitness in Adults Older Than 50 Years of Age," PubMed Central, 2021. ↩

6. Velislava Todorova, "Ecdysterone and Turkesterone—Compounds with Prominent Potential in Sport and Healthy Nutrition," PubMed Central, 2024. ↩

7. Colin D Wilborn, "Effects of Methoxyisoflavone, Ecdysterone, and Sulfo-Polysaccharide Supplementation on Training Adaptations in Resistance-Trained Males," PubMed Central, 2006. ↩