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Lemon balm and calmness: grade C

Limited evidence. Direction: No effect.

C LimitedShort-term onlySubjective outcome onlySingle research group

Educational guidance, not medical advice

Why this grade

Rubric condition met: Small acute crossover trials from one research group with dose-inconsistent positives, plus one larger parallel trial null on calmness as its primary outcome

Three placebo-controlled crossover trials of 18 to 20 healthy volunteers, mostly young adults, all with DO Kennedy and AB Scholey as authors, found higher Bond-Lader calmness after a single dose, but at a different dose in each trial. The only larger trial, a preregistered parallel-group trial of 106 young adults with moderate stress funded by the ingredient supplier Givaudan France Naturals, found no change in overall calmness, its primary outcome, though transient calmness recovered after cognitive demand. Funding of the three earlier trials is not stated. Mixed, short-term, self-rated findings give C with direction none.

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)2000200520102015202020252030RCTCrossover RCTMathews 2026, 2026: RCT, n = 106, result not recordedKennedy 2003, 2003: crossover RCT, n = 20, result not recordedKennedy 2002, 2002: crossover RCT, n = 20, result not recordedKennedy 2004, 2004: crossover RCT, n = 18, result not recorded
each study this grade rests on, by publication year and design. Solid: effect versus the comparator; half-filled: mixed; hollow: no effect; dashed: result not recorded yet. Larger marks had more participants.
Show the numbers
StudyYearDesignParticipantsResult
Kennedy 20022002crossover RCT20result not recorded
Kennedy 20032003crossover RCT20result not recorded
Kennedy 20042004crossover RCT18result not recorded
Mathews 20262026RCT106result not recorded

The acute effects of Zensera™ (Melissa officinalis L.) extract on mood and cognitive performance during cognitive overload: a randomised placebo-controlled, double-blind study in healthy young adults with moderate subjective stress.

Mathews I, Eastwood J, Bell L. The acute effects of Zensera™ (Melissa officinalis L.) extract on mood and cognitive performance during cognitive overload: a randomised placebo-controlled, double-blind study in healthy young adults with moderate subjective stress Ther Adv Psychopharmacol, 2026. PMID 41782777

Result not recorded
Design
Randomized, double-blind, placebo-controlled, parallel-group trial (single dose)
Sample
n = 106
Population
Healthy young adults with moderate subjective stress
Funding
Givaudan France Naturals (PhD studentship); two authors employed by Givaudan France Naturals

Attenuation of laboratory-induced stress in humans after acute administration of Melissa officinalis (Lemon Balm).

Kennedy DO, Little W, Scholey AB. Attenuation of laboratory-induced stress in humans after acute administration of Melissa officinalis (Lemon Balm) Psychosom Med, 2004. PMID 15272110

Result not recorded
Design
Randomized, double-blind, placebo-controlled, balanced crossover trial (single doses, laboratory stressor)
Sample
n = 18
Population
Healthy volunteers
Funding
not stated in the PubMed or Crossref record; full text not read

Modulation of mood and cognitive performance following acute administration of single doses of Melissa officinalis (Lemon balm) with human CNS nicotinic and muscarinic receptor-binding properties.

Kennedy DO, Wake G, Savelev S. Modulation of mood and cognitive performance following acute administration of single doses of Melissa officinalis (Lemon balm) with human CNS nicotinic and muscarinic receptor-binding properties Neuropsychopharmacology, 2003. PMID 12888775

Result not recorded
Design
Randomized, double-blind, placebo-controlled, balanced crossover trial (single doses)
Sample
n = 20
Population
Healthy young adults
Funding
not stated in the PubMed or Crossref record; full text not read

Modulation of mood and cognitive performance following acute administration of Melissa officinalis (lemon balm).

Kennedy DO, Scholey AB, Tildesley NT. Modulation of mood and cognitive performance following acute administration of Melissa officinalis (lemon balm) Pharmacol Biochem Behav, 2002. PMID 12062586

Result not recorded
Design
Randomized, double-blind, placebo-controlled, balanced crossover trial (single doses)
Sample
n = 20
Population
Healthy young adults
Funding
not stated in the PubMed or Crossref record; full text not read

Search and history

Search (): (melissa[ti] OR "lemon balm"[ti]) AND (mood[tiab] OR calmness[tiab] OR stress[tiab]) AND (healthy[tiab] OR volunteers[tiab])

  • Graded C (proposed): Proposed in the monograph draft
  • C to C (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page