NutriStack
Testosterone and Vitamin D3, a synergy.
Vitamin D deficiency is associated with lower testosterone in observational studies, but a high-quality RCT showed that 20,000 IU/week vitamin D3 for 12 weeks did not raise testosterone in healthy men with low vitamin D. Vitamin D is still worth correcting for general health and bone protection during testosterone therapy.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Testosterone and Vitamin D3
- Pair type
- Synergy
- Evidence (highest tier)
- Strong
- Source citations
- 2 sources
- Stack Score effect
- +2 to your Stack Score (per scored synergy row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Synergy · Strong evidence
Synergy
What is happening. Vitamin D deficiency is associated with lower testosterone in observational studies, but a high-quality RCT showed that 20,000 IU/week vitamin D3 for 12 weeks did not raise testosterone in healthy men with low vitamin D. Vitamin D is still worth correcting for general health and bone protection during testosterone therapy.
Mechanism. Vitamin D receptors exist in Leydig cells, but RCT evidence does not support a direct testosterone-raising effect. Vitamin D's value during TRT lies in bone protection, calcium absorption, and immune function.
Recommendation. Take vitamin D3 800-2000 IU/day while on testosterone therapy to support bone health, not as a testosterone booster. Aim for serum 25(OH)D above 30 ng/mL. Take with a fatty meal.
Sources (2)
- Lerchbaum E, Pilz S, Trummer C, et al. Vitamin D and Testosterone in Healthy Men: A Randomized Controlled Trial. J Clin Endocrinol Metab. 2017;102(11):4292-4302. PMID 28938446
- Catalano A, Bellone F, Morabito N, et al. Vitamin D Boosts Alendronate Tail Effect on Bone Mineral Density in Postmenopausal Women with Osteoporosis. Nutrients. 2021;13(6):1878. PMID 34072655
Stack Score
How this pair moves the number.
Effect on the composite score
If both Testosterone and Vitamin D3 are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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