Shilajit testosterone or mitochondrial: Agwaan et al., 2026
An animal trial on 18 female Awassi lambs found that 100 mg/kg bodyweight shilajit daily over three summer months increased weight gain, reduced cortisol, and improved red blood cell counts compared to controls. This is an animal model with translational limits — lambs aren't men, and the dose doesn't scale directly to humans — but it adds to the physiological plausibility that shilajit supports stress resilience and metabolic function under heat stress.
Key takeaways
- 18 lambs divided into three groups (control, 50 mg/kg, 100 mg/kg shilajit) over three months during summer heat.
- 100 mg/kg group showed lower cortisol, higher thyroid hormones (T3/T4), improved hemoglobin and hematocrit, and better weight gain versus control.
- Study measured oxidative stress markers and found reductions in the treated groups.
- This is an animal model — physiological responses in lambs during heat stress don't translate one-to-one to human performance, recovery, or testosterone optimization.
- The dose in lambs (100 mg/kg) is roughly 7 grams for a 70 kg human if scaled by bodyweight, far higher than typical human supplementation (300-500 mg/day). Direct extrapolation is inappropriate.
The study
Agwaan et al., Open Veterinary Journal, 2026. PubMed link. 18 female Awassi lambs, 4 months old, divided into three groups of six. Control group received no shilajit. Treatment groups received either 50 mg/kg or 100 mg/kg bodyweight shilajit daily, administered orally with their standard diet. Duration was three months, from June through August, corresponding to peak summer heat in the study region. Blood samples collected monthly. Measurements included growth rate (bodyweight gain), cortisol, thyroid hormones (T3, T4), complete blood count (RBCs, WBCs, hemoglobin, hematocrit), glucose, total protein, liver enzymes (ALT, AST), cholesterol, and oxidative stress markers (malondialdehyde, superoxide dismutase, catalase). No blinding reported. No pre-registration mentioned. Published in a veterinary journal focused on livestock health and production.
How to read this study
What this paper does well: It measures a broad panel of metabolic and stress markers — cortisol, thyroid hormones, oxidative stress enzymes — not just weight gain. That gives mechanistic insight into how shilajit might be working. The three-month duration is long enough to see physiological adaptation, not just acute responses. The sample size is appropriate for an exploratory animal trial; six per group is standard in livestock research, though it would be underpowered in a human RCT. The study was conducted during summer heat stress, which is ecologically relevant for the hypothesis that shilajit supports stress resilience.
What this paper is missing or weak on: No blinding. The researchers knew which lambs got which dose, which introduces bias in subjective assessments (though weight and blood markers are objective). The abstract doesn't report confidence intervals or p-values for the key findings — we don't know the precision or statistical significance of the cortisol reduction or thyroid increases. Most importantly, this is an animal model. Lambs are ruminants with different digestive physiology, different hormonal regulation, and different metabolic demands than humans. Heat stress in livestock is a specific physiological challenge that doesn't map cleanly onto human performance or aging.
How I'd weight this paper: This is hypothesis-generating, not evidence for human use. Animal models are valuable for establishing biological plausibility and guiding human trials, but they can't establish efficacy in people. I treat this as one more data point that shilajit has measurable anti-stress and metabolic effects in a living system, which increases confidence that the fulvic acid mechanism is real. But I don't use it to justify dosing recommendations for men. For that, I need human RCTs.
What they found
Lambs receiving 100 mg/kg shilajit gained more weight over the three-month period compared to controls, though the abstract doesn't provide the exact numbers. Cortisol levels were lower in the 100 mg/kg group, indicating reduced stress response. Thyroid hormones T3 and T4 were elevated, suggesting improved metabolic rate. Hemoglobin and hematocrit increased, along with red and white blood cell counts. Glucose, total protein, and cholesterol were higher in treated groups. Liver enzymes (ALT, AST) also increased, which the authors interpret as increased metabolic activity, though elevated liver enzymes can also signal hepatic stress. Oxidative stress markers — specifically malondialdehyde, a marker of lipid peroxidation — were reduced. Antioxidant enzymes superoxide dismutase and catalase were higher, consistent with improved redox balance. The 50 mg/kg group showed intermediate effects between control and 100 mg/kg, suggesting a dose-response relationship. Statistical significance and effect sizes are not reported in the abstract.
What it means for the average man
This study doesn't tell you what dose of shilajit to take. The 100 mg/kg dose that worked in lambs would scale to roughly 7 grams per day for a 70 kg man if you extrapolated by bodyweight, which is not how interspecies dosing works. Typical human shilajit supplementation is 300-500 mg/day, based on human trials. What this paper does is add to the biological plausibility that shilajit has real physiological effects — reducing cortisol, supporting thyroid function, improving antioxidant capacity — under metabolic stress. Those are mechanisms that could matter for men under training stress, sleep debt, or aging-related oxidative load. But you need human trials to confirm benefit and establish dose. If you're already taking shilajit, this supports the hypothesis that it's doing something measurable. If you're considering it, this doesn't change the calculus — look to human data first.
The caveats
Lambs aren't men. Ruminant physiology, especially digestive and hormonal systems, differs substantially from humans. Heat stress in livestock is a specific challenge that doesn't replicate the stressors most men face — training recovery, cognitive load, sleep disruption. The dose used (100 mg/kg) is far higher than typical human supplementation, and bodyweight scaling across species is unreliable. The study didn't report statistical significance, confidence intervals, or effect sizes, so we can't assess the precision or reliability of the findings. Elevated liver enzymes (ALT, AST) were noted as increased metabolic activity, but sustained elevation can also indicate hepatic stress — the paper doesn't clarify whether this is adaptive or a red flag. No human trials have replicated these findings at comparable doses.
Frequently asked questions
Can I use animal studies to decide on supplementation?
Animal studies establish biological plausibility — they show that a compound has measurable effects in a living system — but they don't establish efficacy or safety in humans. Metabolism, absorption, dose sensitivity, and hormonal regulation differ across species. Use animal data to inform hypotheses, not dosing decisions. For those, you need human RCTs.
How do I scale an animal dose to humans?
You don't, at least not by bodyweight. Interspecies dose conversion uses body surface area or allometric scaling, which accounts for differences in metabolic rate. A 100 mg/kg dose in a 30 kg lamb is roughly 3 grams total. The equivalent human dose by surface area scaling is closer to 500-700 mg for a 70 kg man, not 7 grams. But this is still speculative — the correct human dose comes from human trials, not extrapolation.
Does this study prove shilajit lowers cortisol in men?
No. It shows cortisol reduction in heat-stressed lambs. Human trials on shilajit and cortisol are sparse. One small human trial (Pandit et al., 2016) showed improved stress resilience and lower anxiety scores in men, but cortisol wasn't the primary endpoint. This lamb trial adds mechanistic support, but it doesn't substitute for human data.
What about the liver enzyme increases?
The authors interpret elevated ALT and AST as signs of increased metabolic activity, which is plausible under anabolic conditions (growth, thyroid stimulation). But sustained liver enzyme elevation can also indicate hepatotoxicity. The paper doesn't report whether these increases stayed within normal range or if there were other signs of liver stress. In human supplementation, shilajit at standard doses (300-500 mg/day) hasn't shown hepatotoxicity in published trials, but this animal dose was much higher.
Sources
- Agwaan H. The physiological effects of administering different concentrations of Shilajit to Awassi lambs and their impact on productive trait and blood parameters and some biochemical measurements. Open Vet J. 2026. PubMed.
- Pandit S, et al. Clinical evaluation of purified Shilajit on testosterone levels in healthy volunteers. Andrologia. 2016;48(5):570-575.
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