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User supplement reviews: a valuable research tool

reference, research, reviews

For years I’ve used the customer reviews at online health food stores to learn about experiences other people were having with various supplements and health issues.

These reviews are some of the most useful references I’ve found about vitamins, minerals, herbs, glandulars, etc. We’ve been taught to mistrust personal observations of the Average Joanna about her medical issues, but I have found thoughtful and perceptive comments there.

I stick to two online retailers for this type of research — the majority of the time and Amazon only occasionally. I don’t actually order from Amazon due to all the reports about counterfeiting. Vitamin Shoppe’s customer reviews are almost non-existent. GNC seems to be at least trying with its review section, but has very few brands to choose from.

The review sections on iHerb and Amazon have their own search bar, which speeds things up when you’re trying to find a link between manganese and hirsutism, or the long-rumored connection between vitamin C and demon possession.

What you can learn from the decent reviews

You’ll never find all the data points listed below in any one review, but you can accumulate a lot of info if you trawl through the sprawl.

Ideally, in a perfect world, customers would include the following info in their supplement review:

  • What health complaint or condition led them to try it.
  • What gave them the idea to try it.
  • What dosage and frequency they used.
  • How long they’d been taking it.
  • How long before they noticed an effect.
  • Whether it resolved any aspect of the condition.
  • What side effects they experienced.

Other information I find helpful:

  • If the supplement stopped working after a while.
  • Other approaches, nutritional therapy or otherwise, they tried.
  • Ideas about the cause of the condition.
  • If using the supplement became a financial burden. 
  • If they suspect that the formula has been changed, or notice a change in appearance of the capsules.
  • How it compares to similar products by other brands.

How to actually find iHerb’s customer reviews search bar

You could go nuts looking for it, so be warned.  Don’t get it mixed up with the search bar in the Questions & Answers section.

  • Scroll to the bottom of the product page, to the last review.
  • Click on the link below the last review that says, “See all 2,543 reviews.”
  • On the resulting page, on mobile devices, the search bar will be below Customer Images, and before you get to the reviews. On desktops, the search bar will be on the left sidebar, below the Write a Review button. 

Searching the reviews using iHerb’s main search bar 

If you use iHerb’s main website search bar, under the Search Results you’ll see an option to search Customer Reviews for your term. It’s more obvious on mobile than on desktop. This is handy if you want to, say, see every supplement review that mentions asthma, and get an overview of what people are using. It’s easier on desktop, on a big monitor, to see patterns — the search term is highlighted and you can see a lot more at once. On a phone, it’s a death scroll. 

This isn’t the way to search for reviews of a particular supplement, however  —  it looks for terms in the reviews themselves, and people don’t usually repeat the name of the product in their review. If you want to know what people are saying about asthma who’ve purchased the product “Zanzibar Nights Maximum Manliness Powdered Reishi Mushroom Cap,” you’d go to that product page, and then to the review section.

Tricks to searching the reviews

  • I’ve found that five supplement brands seem to generate the most articulate and intelligent reviews — Thorne, Life Extension, Jarrow, Source Naturals, and Doctor’s Best — but I don’t necessarily favor them when it comes to making a purchase.
  • If there are too many reviews to deal with, turn off the auto-translated reviews. On iHerb at least they have a greater percentage of crappy reward or affiliate reviews (more about that below).
  • Narrow them down further if necessary by selecting just the 4-star reviews. Does anyone really trust 5-star reviews?
  • Search one word, or one very common phrase, at a time. These are regular people writing, not SEO experts. If you’re looking for accounts of how milk thistle helps stigmata, try “palm,” “hands,” “bleeding,” etc.

Avoid the vacuous and suspect reviews

On, don’t bother reading an unusually long review until you confirm that the last sentence doesn’t ask you to click through to the writer’s “individual program page.” These reviews, by members of the store’s affiliate or reward programs, typically consist of a litany of textbook facts about how the supplement’s ingredients work in the body, with no references or sources. Nor does the copy mention any personal experience with the product.

Other suspect content I’ve noticed:

  • Multiple people marking these vacuous entries as “helpful.”
  • The same review repeated one after the other, up to three at a time.
  • Multiple reviews saying essentially the same thing in the same number of sentences, but worded slightly differently, and by different user names.

I’ve got nothing against the parties involved in these manipulations. The 2022 top earner of iHerb’s rewards program made more than $600,000! Good on them. But I wish someone would trim some of the most blatant padding.


This content was first published on June 10, 2023 and updated on September 15, 2023.

Marjorie smiling, wearing an orange shirt.

Marjorie R.

Marjorie is the creator of, a record of her and her guest authors’ experiences with non-prescription health solutions. She is a third-generation nutritional-therapy self-experimenter.

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