What kind of interaction is it?

Caution: an interaction that may reduce efficacy or raise side-effect risk and warrants monitoring.

Is this interaction backed by published research?

Yes. NutriStack lists 2 citation rows for the Ashwagandha + Testosterone pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Interaction databaseSupplement × PrescriptionReviewed May 2026

Ashwagandha and Testosterone, a caution.

Q: Can I take Ashwagandha and Testosterone together?

Possibly, but with caution. Ashwagandha and Testosterone have a documented caution-tier interaction. Ashwagandha (Withania somnifera) modestly raises testosterone and LH in men with infertility or stress and can also raise T4 and lower TSH. Adding it to prescribed testosterone may amplify androgenic effects and complicates monitoring, especially of thyroid function which can already be affected by androgen therapy.

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored caution row.

Ashwagandha (Withania somnifera) modestly raises testosterone and LH in men with infertility or stress and can also raise T4 and lower TSH. Adding it to prescribed testosterone may amplify androgenic effects and complicates monitoring, especially of thyroid function which can already be affected by androgen therapy.

2 primary source citations. Moderate evidence. Last verified May 30, 2026.

Open the interaction checker →Read the methodology

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.

Sourcing standards·Evidence tiers

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: Ashwagandha and Testosterone
Pair type: Caution
Evidence (highest tier): Moderate
Source citations: 2 sources
Stack Score effect: −5 to your Stack Score (per scored caution row).
Scope: Supplement × Prescription
Last verified: May 30, 2026

Caution · Moderate evidence

Caution

What is happening. Ashwagandha (Withania somnifera) modestly raises testosterone and LH in men with infertility or stress and can also raise T4 and lower TSH. Adding it to prescribed testosterone may amplify androgenic effects and complicates monitoring, especially of thyroid function which can already be affected by androgen therapy.

Mechanism. Ashwagandha withanolides modulate the HPA axis and may increase Leydig cell steroidogenesis. They also stimulate thyroid hormone synthesis, raising T4 and lowering TSH. Both effects can compound those of exogenous testosterone.

Recommendation. Use ashwagandha cautiously while on prescribed testosterone. If you take both, monitor hematocrit, PSA, mood, and a TSH check every 6-12 months because ashwagandha can shift thyroid labs. Discontinue ashwagandha if you develop thyrotoxicosis symptoms (palpitations, heat intolerance, tremor).

Sources (2)

Stack Score

How this pair moves the number.

Effect on the composite score

If both Ashwagandha and Testosterone are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).

The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.

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