Amount of me­la­tonin in sup­ple­ments can vary widely

What’s on the la­bel and what’s in­side the bot­tle are not al­ways the same, Univer­sity of Guelph re­searchers find

The Hamilton Spectator - - HEALTH - SH­ERYL UBELACKER

TORONTO — Re­searchers have mea­sured lev­els of me­la­tonin in a num­ber of over-the­counter sup­ple­ments sold in Canada and found amounts of the hor­mone can vary dra­mat­i­cally from what’s listed on the prod­ucts’ la­bels.

Me­la­tonin is pro­duced in the brain and oc­curs nat­u­rally in small quan­ti­ties in some meats, grains, fruits and veg­eta­bles. Sup­ple­ments con­tain­ing me­la­tonin are of­ten taken by peo­ple in a bid to over­come sleep prob­lems.

A study by the Univer­sity of Guelph, pub­lished this week in the Jour­nal of Clin­i­cal Sleep Medicine, tested 30 me­la­tonin sup­ple­ments pro­duced un­der 16 brand names and sold in gro­cery and drug stores.

The re­searchers found 71 per cent of the prod­ucts — which were not iden­ti­fied by name — did not meet la­bel claims. Higher-than-listed amounts of me­la­tonin ranged be­tween 12 and 25 per cent on av­er­age, but some prod­ucts had nearly five times the hor­mone they were said to con­tain.

One chew­able tablet, for in­stance, con­tained more than eight mil­ligrams of me­la­tonin, a 478 per cent in­crease over the 1.5 mil­ligrams shown on its pack­ag­ing.

Oth­ers were found to have me­la­tonin lev­els lower than what was listed.

One sup­ple­ment, which also con­tained laven­der, camomile and lemon balm, had 83 per cent less me­la­tonin than the three mil­ligrams each cap­sule was sup­posed to con­tain.

Prin­ci­pal in­ves­ti­ga­tor Praveen Sax­ena, a pro­fes­sor in the univer­sity’s depart­ment of plant agri­cul­ture, said amounts of me­la­tonin in the sup­ple­ments tested some­times var­ied from lot to lot within the same prod­uct line.

Of even more con­cern was that about a quar­ter of the sup­ple­ments also con­tained sero­tonin, a neu­ro­trans­mit­ter in­volved in mood reg­u­la­tion and nerve im­pulse trans­mis­sion, which was not in­cluded in the prod­ucts’ ingredients lists and could cause ad­verse ef­fects.

“Mil­lions of peo­ple use me­la­tonin for a va­ri­ety of pur­poses, in­clud­ing as a sleep aid and for jet lag,” said Sax­ena. “Th­ese prod­ucts are of­ten self-pre­scribed, so it’s im­por­tant that la­bels are ac­cu­rate and the prod­ucts free from con­tam­i­nants.”

Sero­tonin is a reg­u­lated sub­stance that’s not au­tho­rized for sale as a sup­ple­ment. Ingest­ing ex­cess amounts of the neu­ro­trans­mit­ter could lead to side-ef­fects, in­clud­ing what’s known as sero­tonin syn­drome — a po­ten­tially life-threat­en­ing con­di­tion. Peo­ple who take an­tide­pres­sants called se­lec­tive sero­tonin re­up­take in­hibitors, or SSRIs, might be sus­cep­ti­ble to ad­verse ef­fects if they were to take a me­la­tonin sup­ple­ment that also con­tained sero­tonin.

Dr. Brian Mur­ray, a neu­rol­o­gist at Toronto’s Sun­ny­brook Health Sci­ences Cen­tre who spe­cial­izes in sleep dis­or­ders, said the study’s find­ing of huge vari­abil­ity in me­la­tonin lev­els in sup­ple­ments is con­cern­ing.

“Many peo­ple are us­ing it, and if they are us­ing it, who knows what they’re get­ting?” said Mur­ray, who was not in­volved in the study.

He does not rec­om­mend tak­ing me­la­tonin for sleep is­sues. Ev­i­dence shows the hor­mone may have a role to play in re­set­ting a per­son’s in­ter­nal cir­ca­dian rhythms, but it’s “not a good sleep­ing pill.”

“It’s not go­ing to make you sleep more, it’s not go­ing to make you sleep deeper, but it might change the time when you have that sleep.”

Me­la­tonin can also in­ter­act with a num­ber of pre­scrip­tion med­i­ca­tions — in­clud­ing an­tide­pres­sants, blood pres­sure reg­u­la­tors and blood thin­ners — and should not be taken with­out first check­ing with a health-care provider. Sax­ena said me­la­tonin, which oc­curs nat­u­rally in some plants, is an un­sta­ble mol­e­cule and in sup­ple­ment form may be af­fected by en­vi­ron­men­tal con­di­tions.

“For ex­am­ple, man­u­fac­tur­ers make them and then they are trans­ported in trucks — we don’t know what the tem­per­a­ture was there and the stor­age con­di­tions.”

Dif­fer­ences among batches or im­proper mix­ing might also cause vari­abil­ity in me­la­tonin con­tent, al­though it’s pos­si­ble that ex­tra me­la­tonin was added dur­ing man­u­fac­tur­ing to en­sure a longer shelf life, he spec­u­lated.

“We wanted to help bring the point for­ward and not point fin­gers be­cause we don’t re­ally be­lieve that it is in­ten­tional,” he said.

“I think it’s more like this is a find­ing that can help con­sumers and help man­u­fac­tur­ers im­prove pro­duc­tion qual­ity.”

He­len Long, pres­i­dent of the Cana­dian Health Food As­so­ci­a­tion (CHFA), said mem­bers strive to en­sure con­sumers have ac­cess to nat­u­ral health prod­ucts that are safe, ef­fec­tive and of high qual­ity.

“The pub­lished re­sults do not ad­e­quately ex­plain the cause of the re­ported vari­abil­ity,” Long said in a state­ment, “and we would wel­come fur­ther re­search to un­der­stand the ex­ter­nal fac­tors that could lead to vari­abil­ity or in­sta­bil­ity of me­la­tonin.”


Prof. Praveen Sax­ena of the Univer­sity of Guelph found that amounts of me­la­tonin in the sup­ple­ments tested some­times var­ied from lot to lot within the same prod­uct line.

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