Short answer: the key ingredient has a published human trial behind it, and Testosil uses it at the dose that trial used. In that study, men who trained and supplemented raised testosterone by 96.2 ng/dL over 8 weeks, against 18.0 ng/dL for men who trained with a placebo.
| Detail | What it was |
|---|---|
| Design | Double blind, placebo controlled |
| Participants | 57 men, ages 18 to 50 |
| Duration | 8 weeks |
| Dose | 300mg of the extract, twice daily |
| Both groups | Resistance training for the full 8 weeks |
| Result, supplement group | +96.2 ng/dL testosterone |
| Result, placebo group | +18.0 ng/dL testosterone |
| Statistical significance | p=0.004 |
Double blind placebo controlled means neither the participants nor the researchers knew who received what until the data was analyzed. It is the design that filters out expectation, and it is the reason this result carries more weight than a before and after photo.
96.2 divided by 18.0 is roughly 5.3. The supplemented group's increase was about 434% greater than the increase training produced on its own. That is the figure quoted on the label, and the asterisk is doing real work: it is a comparison between two increases, not a 434% rise in testosterone.*
That second column is not a mark against the product. It is what honest reading of a study looks like, and knowing it tells you exactly how to use the product so that you are using it the way it was tested.
If you train consistently, take two servings daily, and give it 8 weeks, you are using it under the conditions the research used. That is the most honest answer available: the evidence supports that scenario, and it does not speak to the others.
If you are not training, the study has nothing to say about your situation, because every participant in it exercised.
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The key ingredient has a published double blind placebo controlled trial behind it, and Testosil uses it at the studied dose. In that 8 week study of 57 men aged 18 to 50, the group doing resistance training plus the supplement increased testosterone by 96.2 ng/dL, compared with 18.0 ng/dL for the group doing the same training with a placebo, significant at p=0.004. Individual results vary.
Testosil is made by Leading Edge Health, a company operating since 2001 with a listed business address. The formula uses KSM-66 Ashwagandha at the dose used in published research, and the manufacturer backs it with a lifetime money back guarantee on direct orders.
The supporting study ran 8 weeks with participants training throughout. That is the timeframe the evidence covers, which is why the 90 day supply is the common choice rather than a single bottle.
The study behind the key ingredient enrolled men aged 18 to 50, so it does not directly cover men over 50. The ingredients remain the same, but the specific research result applies to that age range.
There is no evidence either way. In the supporting study, both the supplement group and the placebo group did resistance training for all 8 weeks, so the research does not test the supplement on its own.
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Daily Gear Digest covers supplements and performance products for men. Figures come from the clinical research the manufacturer cites and from the product label, with study conditions stated so you can judge them yourself. We earn a commission when you buy through our links, and we are not the manufacturer or seller of this product.
* In a clinical study of one ingredient, men taking that ingredient alongside exercise experienced a 434% greater increase in testosterone compared to men who exercised with a placebo, at a dosage equivalent to two servings of Testosil.
Medical disclaimer. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This page is for information only and is not medical advice. Consult a qualified healthcare provider before starting any supplement.
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Results disclaimer. Individual results vary. Study figures describe group averages under specific conditions including supervised resistance training, and are not a prediction of individual results.