Research review
Valerian root: what the research does and doesn't show
No trial has tested valerian's safety in pregnancy or breastfeeding, and none of the research reviewed here isolated weight gain, constipation, diarrhea, headaches, or pain as a specifically measured outcome.
Valerian root's research base doesn't answer many of the questions people search for most: there's no dedicated safety study in pregnancy or breastfeeding, no trial measuring weight change, and no trial isolating constipation, diarrhea, headaches, or pain as an outcome. Here's what the human research that does exist actually tested — and where it stops.
What the evidence doesn't support
It doesn't support valerian root, in any form or dose, as something evaluated for safety in pregnancy or breastfeeding — no trial has tested either. It doesn't support a specific link to weight gain, constipation, diarrhea, or headaches: no trial reviewed here measured any of those as a dedicated outcome. And it doesn't support pain relief — no trial tested valerian for pain.
What the trials found
No trial has tested valerian's safety in pregnancy. A multinational survey of 9,459 pregnant women across 23 countries found valerian among the most commonly used herbs during pregnancy, alongside ginger, cranberry, and raspberry — a usage figure, not a safety finding (PMID 24330413). Common use during pregnancy isn't the same as established safety, and no controlled trial fills that gap.
A national reference database on medications in lactation states there's no published safety or efficacy data on valerian in nursing mothers or infants. It often advises against use while breastfeeding because valepotriate and baldrinal, two of valerian's compounds, have shown cytotoxic and mutagenic activity in lab (in vitro) testing — a lab-level finding used as a precaution, not a documented harm in a nursing infant (PMID 30000874).
No trial identified for this page isolated constipation, diarrhea, or headaches as a specifically measured outcome. The closest data is general: a national reference database describes valerian as generally well tolerated, with dizziness, hangover, or headache reported occasionally (PMID 30000874), and a 2007 review of 37 studies concluded it's a safe herb with only rare adverse events overall (PMID 17517355). Neither breaks out digestive symptoms specifically, so there's no dose-response or incidence figure to report for constipation, diarrhea, or headache.
No trial reviewed here measured body weight or pain as an outcome. There's no research basis, for or against, on either question.
A 2020 systematic review of 60 valerian studies noted that, across the studies it pooled, participant ages ranged from 7 to 80, with no severe adverse events associated with valerian intake across that range (PMID 33086877). That's a description of who happened to be enrolled across a mix of studies, not a dedicated pediatric safety or dosing trial — there's no established dose for children, and this page doesn't provide one.
Questions people ask
Is valerian root safe in pregnancy?
No trial has tested it. Valerian is among the most commonly used herbs in pregnancy per a large multinational survey, but common use isn't the same as established safety (PMID 24330413). Ask a doctor before taking any supplement while pregnant.
Is valerian root safe for breastfeeding?
No published safety data exists in nursing mothers or infants, and it's often not recommended while breastfeeding due to lab-level toxicity findings in some of its compounds (PMID 30000874). Ask a doctor before using it while nursing, especially with a newborn or preterm infant.
Can valerian root cause constipation?
No trial identified for this page tracked constipation as an outcome. There's no research basis to answer this either way.
Can valerian root cause diarrhea?
No trial identified for this page tracked diarrhea as a specifically measured outcome. General safety reviews describe valerian as well tolerated overall, without breaking out digestive symptoms.
Can valerian root cause headaches?
A national reference database lists headache as one of the occasional side effects reported with valerian, alongside dizziness and hangover (PMID 30000874), but no trial isolated why or how often it happens. If a headache follows starting valerian, stopping and checking with a doctor or pharmacist is a reasonable next step.
Can valerian root cause weight gain?
No trial reviewed here measured weight as an outcome. There's no research basis to answer this either way.
Does valerian root help with pain?
No trial reviewed here tested valerian for pain, nerve pain, or any pain-related outcome. There's no research basis for that use.
Is valerian root safe for kids?
No dedicated pediatric trial or established children's dose exists. A large systematic review noted some pooled studies included participants as young as 7 without a severe-adverse-event signal, but that isn't the same as safety or dosing guidance for children. Ask a pediatrician before giving any supplement, valerian included, to a child.
When to talk to a doctor
A doctor is the right first stop for using any supplement during pregnancy or while breastfeeding, for a child, or alongside a persistent symptom like ongoing pain, headaches, or digestive changes. Valerian root isn't studied well enough to rule in or out for any of those, and it isn't a treatment for an underlying condition behind them.
Related reading: who should not take valerian root?, valerian root side effects, and valerian root benefits: what the research does and doesn't show.
Sources
- Herbal medicine use in pregnancy: results of a multinational study A multinational survey of 9,459 pregnant women found valerian among the most commonly used herbs in pregnancy, without evaluating its safety.
- Valerian A national reference database on medications describes valerian as generally well tolerated, with occasional dizziness, hangover, or headache.
- A systematic review of valerian as a sleep aid: safe but not effective A 2007 review titled 'safe but not effective' found valerian's most rigorous, recent trials showed no significant sleep benefit over placebo, while confirming a generally safe profile with rare adverse events.
- Valerian Root in Treating Sleep Problems and Associated Disorders-A Systematic Review and Meta-Analysis A 2020 systematic review of 60 studies found a small, not-statistically-significant pooled effect of valerian on sleep quality overall, a higher (but still uncertain) effect for whole root versus extract, and high heterogeneity in its anxiety meta-analysis; individual trial results ranged from no effect to modest subjective improvement.
*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.