The claim that 'helping makes you happy' has become a staple of pop psychology and self-help manuals.
Performing 'random acts of kindness' has been touted as a sure-fire way of boosting your mood - doing good makes you feel good, as well as benefiting others, researchers said.
A team from the universities of Oxford and Bournemouth in the UK carried out a systematic review of the scientific literature.
They analysed over 400 published papers that had investigated the relationship between kindness and happiness, and identified 21 studies that had explicitly put the claim to the test - that being kind to others makes us happier.
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On this basis, they calculate that there is indeed an overall effect of kindness on happiness, but that the size of the effect is relatively modest - equivalent to less than one point on a 0-10 happiness scale.
They also found that lower quality studies tended to claim larger effects than the high quality research, which suggests that the true effect may be even smaller.
In addition, they note that existing research does not distinguish between kindness to family and friends versus strangers and, taking this into account, targeted kindness rather than indiscriminate kindness may have a greater effect on happiness.
"This research suggests that people do indeed derive satisfaction from helping others. This is probably because we genuinely care about others' welfare, and because random acts of kindness are a good way of making new friends, and kick-starting supportive social relationships," Curry said.
"Offering kindness to others has been explored as a possible panacea for many of our social ills, ranging from social isolation to more serious mental and physical health conditions.