Cross-referencing clinical data
A pairing appears on this page only when a trial gave both ingredients together and measured the result. Withanolide has none that clears that bar.
Stitching two separate single-ingredient studies into a pairing is the one thing this engine will not do. When a study of the combination itself holds up at source, it lands here with its citation.
No invented synergy. Where actives were studied on their own rather than together, the record shows each on its own evidence, never a combined effect no trial measured.
Research strength. Research strength says how much work stands behind the combination. It is never a product score.
Independent record. Every finding is cited to a named trial, dated, and never written by the brand.
20 pairings are live across the library today. Checked 20 July 2026.
No study gave these as a pair, so they are not in the card above. But the reason they belong together is settled biochemistry, not a guess, so it is worth knowing.
Withanolides are the steroidal lactones used to standardise ashwagandha root and leaf extracts, and every clinical trial in this space dosed a standardised extract rather than an isolated withanolide. That means the human data belongs to the extract, with the withanolide percentage acting as an identity and consistency check. Anyone taking ashwagandha is already taking withanolides, so stacking an isolate on top doubles the intake invisibly.
Withanolides are lipophilic steroidal lactones with poor aqueous solubility, which is the constraint every delivery format in this category works around. Phospholipid dispersions and self-emulsifying systems are the standard approach and the reason newer formulations report different exposure profiles. Improved dispersion is a delivery result and is not itself an outcome.
A medium-chain triglyceride carrier keeps withanolides in solution in a softgel and supports micellar dispersion after a meal. It is the simplest answer to the solubility problem in this class. It changes how much dissolves, nothing more.
Magnesium and standardised ashwagandha extract sit together in most evening formulas because both are positioned around sleep quality and calm. Each has its own separate literature and the combination has not been tested against its parts. The pairing is formulation practice.
L-theanine appears alongside withanolide-standardised extracts in stress and focus blends. Their proposed mechanisms are different, so the pairing is about product positioning rather than a shared pathway. Nothing has shown the combination outperforms either alone.
Withanolide-standardised root extracts are used at night for sleep quality, and melatonin shifts sleep timing directly. Stacking both can produce more next-morning grogginess than either alone, particularly at higher melatonin doses. This is a practical caution rather than a documented interaction.
Valerian and withanolide-containing extracts both push in a sedating direction in evening formulas. Combining them raises the chance of daytime drowsiness, which matters for driving and for anyone already on a sedating medicine. No trial has measured the pair together.
Human work with standardised root extract has reported changes in circulating thyroid hormone concentrations, and iodine is the substrate for thyroid hormone synthesis. Anyone stacking both, or taking a thyroid medicine, should have that conversation with their prescriber rather than adjusting on their own. These are marker changes, not clinical outcomes, and the direction is not uniform across studies.
Rhodiola and withanolide-standardised extracts are the two most stacked ingredients in the adaptogen category. Their constituent chemistry is unrelated, so any combined effect would have to be demonstrated rather than assumed. Read it as category convention.
Panax ginseng and Withania somnifera are paired across traditional systems and modern blends aimed at energy and stress resilience. Both carry their own separate human literature. The combination has not been tested as a unit.
Piperine is added to poorly absorbed botanical extracts on the rationale that it slows glucuronidation and raises exposure. The evidence for that with withanolides specifically is thin compared with the curcumin literature. The inhibition is not selective, so it can affect medicines taken at the same time.
Nothing specific on file for Withanolide. Match the label to the daily amount above, and tell your doctor what you take.
Not medical advice. Show the label to your pharmacist.These are the studies our verdict leans on, chosen from the 5 we read for Withanolide. The full linked list is below.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.