St John's Wort

Studies show it helps relieve mild depression, but can you be confident the brand you buy will work?
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  • Updated:13 May 2005


Generally speaking, the stronger the claims that are made, the more rigorous the evidence has to be.

Labels on the SJW products we looked at don't mention the word depression, because making claims about treating or managing depression would be considered very strong and required to be backed up with the highest level of evidence.

This involves considerable trouble and expense, and perhaps from a company's point of view may not even seem necessary – after all, SJW's potential benefits for mild depression are widely known, so why not avoid the direct claim and with it all the bother?

Some products do list symptoms linked to depression for which the product may be a useful remedy, such as "low mood and despondency" and "feelings of sadness and/or tearfulness". By and large, though, you'll find the label claims typically relate to the relief of stress and anxiety. One of SJW's known effects is to reduce anxiety, which can be a symptom or precursor of depression as well as being a condition in its own right.

Any substantial claims should ideally be backed up with good-quality scientific evidence based on clinical trials showing the product's effectiveness. If the product in question hasn't itself been tested, the Therapeutic Goods Administration (TGA) says it's acceptable for the 'sponsor' (the product's manufacturer or distributor) to provide evidence based on trials of other products identical to, or not substantially different from, its product – as long as the sponsor can show this to be the case.

Where's the evidence?

A therapeutic product that's 'listed' by the TGA is allowed to be sold in Australia on the basis that it meets certain safety and quality criteria. As of April 1, 2004, the TGA has required sponsors of listed medicines, including herbal medicines, to hold evidence for claims and indications they make about their products. However, up to now they haven't had to actually produce it until or unless asked. So we figured all we had to do was ask sponsors to show us their evidence, and given that they'd be bound to have it readily to hand (in case the TGA comes knocking on the door), they'd simply have to pop something off to us in the mail.

We invited the sponsors of 27 SJW products to do this: we received evidence for 14; five companies refused to take part, claiming commercial confidentiality as a reason (and one was concerned CHOICE would give it a negative report regardless of what evidence it gave us!); and we didn't hear from the last eight at all, despite contacting them numerous times. See The evidence – who provided what, below, for the brands and sponsors we looked at.

Evaluating the evidence

We asked three people with expertise in the fields of herbal medicines, pharmacology and/or psychiatry to evaluate the quality of the evidence provided to determine whether it backed up the claims made.

As mentioned earlier, sponsors can provide evidence based on products similar to their own, as long as they can prove their similarity. But it can be difficult to prove that one manufacturer's Product A is essentially the same as another manufacturer's Product B that was used in published clinical trials. If they use the same extract (that is, the same SJW source material) at the same dose, equivalence can be shown. Otherwise, there's little option but to test Product A itself to ensure scientific rigour.

Comprehensive evidence was provided for CHEMISTS' OWN, FLORDIS Remotiv, GUARDIAN PHARMACIES, HERRON, HILTON HEALTHSTREAM and MEDIHERB products. Their sponsors provided evidence based on the final product or on the extract used in their product (see The evidence – who provided what, below).

The evidence provided by the rest of the companies that sent us any may adequately meet the TGA evidence requirements (there appears to be some latitude for interpretation). However, they didn't provide us with evidence that contained a clear link between their product and one shown to work in a clinical setting. This doesn't necessarily mean their products don't work just as well as those that gave us comprehensive evidence – just that the evidence given to us wasn't as strong.

As for the companies that didn't take part, they may well have evidence to back up their claims – they just didn't give it to us.

The evidence - who provided what

Comprehensive evidence was provided to back up claims for the following products:

  • Flordis Remotiv, where evidence was based on published papers of clinical trials of the product, which was shown to be effective for mild depression. There's enough information provided on the packaging for a consumer to do their own search for evidence in the medical literature.
  • Chemists' Own, Guardian PHARMACIES, Herron, Hilton Healthstream and Mediherb, where clinical trial evidence was based on products using the same dose of the particular SJW extract used in these products (although the extracts are confidential). Evidence also showed that the product was effective for mild depression.
  • The sponsor of THE HERBALIST (NATURAL HEALTH CONCEPTS) makes claims based on evidence of traditional use, and therefore isn't required to provide scientific evidence, though the evidence provided meets the TGA requirements for traditional use. It also provided details of the extract used, and it's one for which good scientific evidence exists.
  • Evidence for the following brands was considered 'incomplete': the evidence provided consisted of the name of the extract, but not evidence to back up claims made; or evidence that SJW works, but no clear link between that evidence and the particular product. In some cases this was for reasons of 'commercial confidentiality':
    AMCAL, CENOVIS, HERB VALLEY (sponsored by Essential Nutrients), Golden Glow, Nature's Own, NATURE'S WAY (Pharm-a-care), SYAZAK (Swisse Vitamins).
  • The following companies refused to take part in our evaluation of evidence, citing commercial-in-confidence or other reasons:
    Australian NaturalCare Products, Blackmores, Green Valley Nutrition (GNC), Herbs of Gold, Hilde Hemmes.
  • The following companies didn't respond to our request for evidence:
    Bioforce Australia (HYPERIFORCE), Blooms Health Products, Direct Nutritional Supplies (VIGA-VITA), Health World Limited, Healtheries of Australia, Nutrition Care Pharmaceuticals, TP Health (GREENRIDGE), Weleda Australia.

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