HSO’s Part 3 – I Do Not Recommend Prescript Assist

HSO's Part 3 - I Do Not Recommend Prescript Assist

Want to learn all about the HSOs in Prescript Assist? Get a copy of Fix Your Gut.

Everyone in the natural health community loves Prescript Assist; I guess I am a lone wolf. From Sisson, 1 to Asprey, 2 to Kresser, 3 everyone believes that Prescript Assist or HSO’s are the best things since sliced gluten free bread.

The sad thing is most of the time I agree with Kresser, but this time I cannot stand firmly behind one of my mentors.

However, why is that?

Well, in theory, Prescript Assist appears to be a perfect HSO supplement. The “probiotics” found in the supplement are heat and shelf stable. Most of these HSO’s either are encapsulated in endospores or produce biofilm so hopefully they will be able to survive your stomach acid and propagate freely in the large intestine for your benefit.

Endospores are dormant, tough encapsulations that protect the bacteria from your immune system, antibiotics, antibacterials, and even probiotics. Bacteria can also lay dormant in endospores until their environment becomes favorable for faster reproduction and survival. Bacterial endospores may also become opportunistic in a host, share in a “probiotic” communal with other true probiotics for a time, or slowly replicate more bacteria. Bacterial endospores can survive without nutrients for a long time and are resistant to UV radiation, desiccation, high temperatures, extreme freezing, and most chemical disinfectants. 4

Kresser goes as far as to say that the HSO’s found in Prescript Assist are: 5

“Finally, Prescript-Assist microflora are recognized Class 1 Etiological Agents, non-toxic, non-pathogenic, from independently maintained lines — this is well documented in both of the Clinical Therapeutics Articles. More than a decade of use as a supplement has revealed no adverse effects and/or side-effects [including reportedly patients with impaired immune systems], as well as the initial demonstrations with repeated consumptions of doses amounting to 500X that recommended for ordinarily daily use with no ill effect.”

Well, I will be damned, Prescript Assist is the safest HSO supplement known to mankind!

Too bad for Prescript Assist and Kresser insurmountable scientific data proves otherwise.

The Issues with Prescript Assist

It is unknown if most of the HSO’s in Prescript Assist are part of normal human flora. Many of the HSO’s also have non-existent human studies and no research done on human safety. More information about the interaction between these HSO’s and their human hosts might be known once the human microbiome project 6 is completed, but for now it is truly unknown if any of these bacteria are natural flora in your gut microbiome.

You might be asking yourself what is the big controversy.

The main issue is that using any bacteria or yeast with unknown pathogenic capabilities in even healthy and especially sick people is just asking for trouble. Without research, we simply do not know what these organisms are capable of doing to the human body. Are they harmless and help with us with our digestion? Alternatively, are they capable of severe, hard to treat opportunistic infections?

HSO’s That Are Not Considered Normal Human Flora or Have Non-Existent Human Interaction Research in Prescript Assist 7

  • Azospirillum brasiliense
  • Azospirillum lipoferum
  • Bacillus brevis
  • Bacillus marcerans
  • Bacillus pumilus
  • Bacillus polymyxa
  • Bacteroides lipolyticum
  • Bacteroides succinogenes
  • Kurthia zopfii
  • Myrothecium verrucaria
  • Pseudomonas calcis
  • Pseudomonas denitrificans
  • Pseudomonas glathei
  • Streptomyces fradiae
  • Streptomyces cellulosae
  • Streptomyces griseoflavus

Documented Opportunistic HSO’s in Prescript Assist

Remember when Kresser mentioned that the HSO’s in Prescript Assist were non-pathogenic, and no side effects or illnesses have ever been reported from the HSO’s found within the product. Yeah, well I guess he did not do enough research before he made that statement.

  • Acinetobacter calcoaceticus 8 9 10 11
  • Bacillus subtilis 12
  • Phanerochaete chrysosporium 13
  • Bacillus pumilus 14
  • Pseudomonas fluorescens 15 16

All of these listed HSO’s are known to cause opportunistic infections in humans. Pseudomonas fluorescens has even been implicated as the cause of Crohn’s disease (I believe that it is a coinfection instead of being the direct cause.)

These bacteria can produce hardy endospores and / or biofilm, which make it harder to eliminate them if they become opportunistic. It is a lot easier to eliminate opportunistic Lactobacillus acidophilus then Pseudomonas fluorescens.

I hope you now understand why I cannot recommend any of my clients supplement Prescript Assist, and I hope you take my research and do some investigating of these HSO strains on your own.

  1. I’ve had great results with Prescript Assist. I’m hyper sensitive to probiotics as well as prebiotics, and if something doesn’t agree with me I find out right away. Prescript Assist has improved my digestive processes and bowel function dramatically, and the results have lasted. FYI I also pay attention to diet, and work with a functional medicine doctor to fine-tune everything. I have found that the combination of diet and Prescript Assist, along with a prebiotic called Biotagen from Klaire Labs, has worked well for me.

    I’m not here to argue, because I know from personal experience that what works for some people doesn’t work for everybody. Gut issues are highly personal, just as each person’s microbiome is unique to them. There’s no such thing as a one-size-fits-all when it comes to probiotics or diet in general. It is too bad that we don’t have the ability to sample a probiotic for a short period without shelling out $$, and that’s a drawback. But, at least in my case, Prescript Assist has been worth it. It may or may not be worth it for others, but there’s only one way to find out.

  2. Appreciate your perspective.

  3. John — 90% of the studies you post against any probiotic or HSO are never ones based on INGESTING the product. The studies on this page where an individual HSO caused problems were due to hospital equipment being infected with the organism, where people developed problems due to INTUBATION or other medical procedures.

    Next time you go off on a rant about Prescript-Assist or MegaSpore or whatever — try finding human studies where the SBO or HSO or probiotic was ingested, instead of inhaled or as a result of being intubated, etc.

    I just read your comment on Dave Asprey’s forums where you said the first probiotic was named in 1989. That ignorance says everything…unless of course you meant 1889.

  4. So if you don’t reccomend Prescript assist, is there another reseasonably priced probiotic you recommend. I have tried many brands with no luck. I have R/A alot of stomach issues, constipation, and I can’t keep weight on. Im down to 101 lbs and my family is getting worried. i eat a Gluten free diet and have mostly removed all foods that seem to cause RA flares. Thanks for the help

  5. My 33 months son is on intravenous antebiotics in hospital for the last 4 days (pneumonia). Can I give him prescript assist? What’ s the safe dosage? Thank you in advance!

    • Run everything by your doctor but since your son is in a compromised immune state I would heavily advice against the use of Prescript Assist.

    • I do not recommend that he takes PA, he is immunocompromised.

      • Thank you very much for your advice. What about boulardii? Is it not safe too? If that’s the case, GOS is the one you recommend in our case, too?

  6. Hi John – Since you are the only one out there who seems to think Prescript-Assist is not a good idea, I felt you might be the only person to help us out with a very bad problem. I was taking PA and S. bouillardi and they were both helping me a lot. My 22 years old son has a three year history of reflux, stomach ulcers and untreatable anxiety/panic and we have spent three years working to solve any or all of these issues. So I gave him PA and S. bouillardi, just one a day for several days. He definitely had die off since he had a headache and flu-like symptoms, irritability for 2-3 days,but his anxiety was MUCH better, so we thought it was doing what it should – he had been on many different probiotics over the years that never seemed to do anything prior to this. After five days on the PA, his anxiety began to spike up quite badly and got very bad, so we discontinued both the PA and S. bouillardi. His anxiety has moved into full blown panic attacks about irrational, nonsensical subjects but nonetheless, are quite troubling in his current situation of being a college student with a lot of stress anyway. Food allergy tests just showed he is yeast sensitive to brewers yeast, bakers yeast, wheat gluten, dairy and corn. He had already been gluten free for a month or so, but was eating more corn because of this. So now we are completely stumped and his anxiety is out of control and affecting everything in his life. His anxiety actually spikes up after each meal, and I can’t help but wonder what the probiotics have to do with this…All because I thought it was a good idea to share my probiotics with him. We are ordering a stool analysis next week to see what might be the problem but those results are 3 weeks away. I am begging you, if you have any idea where we should start (other than just to read your book, which I probably will…) to reduce his anxiety and panic attacks, we both would be so grateful. No medicines or natural remedies for anxiety are helping any more (GABA, theanine, valerian, etc). Are there other probiotics that can counteract the activity of the PA or S. Bouillardi? I know the latter organism is a yeast, but thought it was a beneficial yeast that would kill off any Candida. I am working with a practitioner but she has had only good results from using PA and S. bouillardi. Any suggestions or direction of where to go with this terrible problem would be greatly appreciated!Thank you in advance…

    • Hi I’m from Norway so pardon my spelling errors.

      My sister struggled with anxiety and racing heart rate as well. Doctors didn’t believe her, never suspected diet to be the issue, accused her of being hypochondriac, which didn’t help her.. She’s now been avoiding all sources of gluten / wheat in her diet for about 2 years. This has made things dramatically better for her and she is now finally back to “normality”.

      I my self (29) struggled with IBS and acid reflux from around when I was 14 years until recently. I remember how I would always know where the nearest toilet facility was. And if I ate a slice of bread before turning in, I’d typically wake up in the middle of the night chocking on stomache acid.

      Thankfully both the IBS and the Acid Reflux cured it self by avoiding first milk(19) which helped tremendously for the IBS then gluten(26) which stopped my Acid Reflux issues completely and after 3 years now I can eat healthy amounts of dairy again. Cheese and yoghurt is fine and i can eat an ice-cream every now and then as long as I avoid gluten. Gluten was the disease, IBS was the symptom and severe milk intolerance was a result.

      Fun fact, the standard lunch at school from when you are 6-18 is bread and milk.

      Although both of us noticed a positive effect very soon after removing gluten from our diets, it did take a long time for the gut to heal and for the symptoms to cease entirely. One thing you must also be aware of is that gluten is often found in products where you least expect it, like soy-sauce, so always read the label first!

      Hang in there, stay away from gluten and wheat and hopefully your gut isn’t damaged beyond repair and things will get better.

      • Holy words, I do believe that gluten, lectins and acellular carbs are the main culprits.
        How is the awareness in your beautiful country? Do people accept that the staple food is a nasty villain? I’m from Italy and people are too brainwashed…

    • I have a sensitivity to corn and rye and barley and eggs, which affect me mentally. Whenever I have any cornflour or cornstarch or any eggs or malted sweetener (made with barley), I get ‘off’. The problem is mentioned by Hulda Clark in her books, but she was not the first to notice it. I think the problem is supposed to be a mold which grows on some crops, which produces an unusual toxin. Apparently it caused an entire town to go insane in the 1700’s in France, due to a contaminated rye crop.

    • Try l-glutamine. Got rid of my panic attacks

  7. I have methane bacteria and have been on two antibiotic my Doctor says no more Iam nausia all the time For three years now will probotic get rid of the bacteria

  8. I’m trying to learn a bit more about prebiotics and probiotics and was advised prescript assist you should only start with 1/4 of a capsule first for 3 days and check for side-effects? If there was a reaction straight away, then you would even start with less for your body to adapt or could it be an indication of unhealthy digestion. Then work your way up to 1/2 capsule, 1 capsule and so forth. What is your view? I understand that this supplement is a native microbe as opposed to the transient microbes, still trying to figure all of this out, and with something like prescript-assist you do not necessarily have to take it long term. I understand your article and where you are coming from; a long time has to pass before any study can be deemed credible but my question as it wasn’t so clear was about how much to start with, not just with this product but any probiotic supplement. Thanks!

    • I would titrate the dosage of any probiotic the same way, it is no different with PA. Start with less amounts of the recommended dosage and increase as your body adapts. Like with Gutpro powder I suggest people start with 1/64 of a tsp daily and increase based off of how you feel.

  9. John,
    I’ve been advised I have leaky gut which is the probable cause of my tendency to food allergies (nuts seeds,vegetables,yeast). I’ve taken Klair Labs Complete for 5 years with no effect on the allergies. What else can be recommended to heal leaky gut and/or indirectly food allergies? Prescript Assist was the new ultimate thing!

    Thanks, Lenore

    • Most of the time taking care of overgrowth and increasing diversity in the gut can help. Ingesting diverse seasonal food, avoiding gluten, limiting casein, ingesting clean protein, if you can tolerate ingesting bone broth or collagen, and ingest EPA / DHA (seafood.) Maybe supplement with GOS or acaia fiber. Working on sleep and circadian rhythm can also help. Finally, getting vitamin D from the sun and maintain safe levels can make a difference.

  10. OH my goodness! I follow the paleo diet for a while now and was doing so well. Over the holidays I ate a few servings of waffles and also had some sugary treats and alcohol…I was a bad girl. My bowels didn’t like it and i started having symptoms of gut dysbiosis. I ordered prescript assist and it started helping me immediately. It has been over a month of taking is and I am having horrible bloating, abdominal pain and constipation. So I guess I am going to stop taking it and hope for the best. I will probably wind up reading your book if my symptoms do not go away. I originally started taking this because The Paleo mom always had such good things to say about it. I wish I had done more research!

  11. I would not be so dogmatic about Prescript Assist. I recently worked with a client who ended up in the hospital, and as a result of the hospital stay, she ended up with C.diff., one of the most serious and life-threatening gut infections. I tried reinoculating her with high dose Sacc. B and multiple strains of Klaire Therbiotic Complete, a probiotic that most of my clients do very well with. In this case, it did not help at all. However, when I suggested she try the Researched Nutritionals Prescript-Assist Pro (SBO), within 3-4 days the gas and bloating stopped and within a week, her stools had normalized. Very dramatic turn-around with this Soil-based organism product. Goes to show that you cannot make gross generalizations about most things and that protocols need to be customized for each person depending on their unique situation and biochemistry. I have come to believe that there is a time and place for the soil based organisms, although they may not be appropriate for everyone (like everything). Judy Loring, CN, Novato, CA

    • I caution the use of soil based probiotics more than even standard probiotics. Granted either one could go sour at anytime. It is always best to try to culture the flora back using targeted prebiotics and food. You final statement is better than most and I applaud you for that. If you want to recommend them to your clients then by all means do so. I will not for mine. The only reason why I wrote the HSO series in the first place was that most people in the blogosphere and the probiotic companies themselves treated them as completely harmless and that they could not cause any problems whatsoever.

  12. I have been able to eat eggs again lately and this coincided with me trying prescript assist. Maybe it cured my intolerance?

  13. Hi John!

    I’ve discovered your page recently and am really enjoying your information – thanks! I am actually in one of your mentor’s practitioner training right now (I’m already a practitioner, just adding to my tools) and am leading a group of people through a Paleo and Microbiome Reset this April. So I’ve been doing extra internet browsing. The SIBO protocol we are learning is not jiving with my own chronic high methane SIBO, so I stopped it. In the past I get worse with any lacto probiotic. I do like bifidus only ones though, and I couldn’t tell a difference either way when I’ve used PA or Probiotic 3. I’m sorting out my thoughts on SIBO and on probiotics right now, so thanks for your dissident viewpoint! Refreshing!

    Laura Paris

  14. Thank you for this article. While I merely understood roughly half of what you said, I now feel reassured that I am NOT crazy sitting here with side effects from this damn pill! It causes me intense gas pain that lasts for days… but only when I take it and eat egg. Very strange. I got it off Amazon and was worried that may have caused a quality control problem, so I call the number and left a message but never got a call back. If this is just “die” that my body needs, I’ll endure. But I have always had a smart body that rejects bad things so I try not to doubt it. I certainly hope I am not putting myself at risk taking these.

  15. i was searching for problems with prescript assist. I also feel sick after taking them. I stop, then try again. This weekend I felt nausea, diarhea and pain in my gut. They are going in the bin. Is there longterm effects of taking it even a bit. i am worried.

  16. Hi John,
    Of the 3 probiotics you mentioned, which one is the best to treat sibo? Jarrow Formulas Ideal Bowel Support or the Life Extension Bifido Gi Balance? Thank you.


  17. Many people seem to have good effect from Prescript assist and I hoped it could help me, I have extreme bacterial overgrowth and really bad bowel flora. Have tried three times. First time my tongue turned yellow and I felt sick. I stopped. Then I tried again, but this time I got extreme gout pain (have never had before), felt sick etc. I tried a third time too, stopped yesterday. I feel sick (or yeah, I was sick before too…but worse) and my tongue is black! I tried to tell myself that PA is really potent and that all these symptoms are some kind of herxheimer reaction, but now I am doubting..

    • I doubt it would help you at this time like most probiotic supplements because of your extreme overgrowth and motility issues.

  18. Discomfort after taking a probiotic, especially a strong one is inevitable. When the bacteria starts to take hold, it kills off the bad stuff. It’s that bad bacteria decaying that causes the discomfort. It can feel nasty due to the variety of symptoms it unleashes but it means the good bacteria is taking hold. It’s a die-off reaction. When you understand it, you don’t fear it.

    Of course with an imbalance of bacteria, that creates food intolerances and they damage the intestines and they need time to heal up so that all the goodness in food is properly absorbed again.

    It’s cheaper to make your own probiotics with fermentation but big drug companies don’t prosper from advocating that.:)

    • It seems to be true! Fermented foods can have way way way higher cfu counts than pills. Like 10 to 1000 times higher than a pill with one serving. That’s the claim I keep reading. Is that so?

  19. Hi, John~
    You seem to be the only one out there down on Prescript-Assist. I wish I would have read you before I took it! I had to take an antibiotic for a UTI and wanted to be heavily proactive in restoring my gut, so decided on PA. I took it for a week, experienced terrible bloating, gas and constipation. Have been off it for a week and am still terribly bloated. I thought it would just go away, but the info you have here on opportunistic HSO’s has me very concerned. Is fixing what I’ve apparently done to myself covered in your book? If so, I will happily purchase it.Thank you for your help. I’m so sorry for the loss of your child.

    • Dear Kimberly,

      Yes, follow the SIBO protocol in my book Fix Your Gut.


    • Kimberly,

      I’m having the exact same issue as you described in this comment. Could you please tell me how you are doing now and what actions you took.

      Thank you,


  20. I took some P. A. a while back, for like 2-3 weeks maybe … I started to develop quite some arthritic pain in my thumb. I NEVER felt that before. P.A. had been my only supplement, nothing changed about my diet or daily habits. SO I strongly suspect P.A. did that to me. I have stopped for 2 months now and the pain is gone. Pfffff …

  21. I’m wondering if taking primal defense caused me my recent relapse with SIBO that I’ve been trying to manage with your protocols for a week. I felt like I was just beginning to tolerate some fermented foods and RS in small quantities. I was taking 1-2 pills of the HSO every other day or so.

    • Dear Dave,

      Any probiotic can become opportunistic and cause SIBO if the conditions are right. The problem with HSO’s is the biofilms that they produce are problematic. Fix Your Gut has some great recommendations in removing the opportunistic bacteria and re-balancing your gut flora!

  22. The information for this can be found in Fix Your Gut.

  23. So what probiotics do you recommend for IBD, Crohn’s, SIBO, antibiotic use and other related things ?

    • I have made a post about probiotics that I recommend here: http://fixyourgut.com/three-recommended-probiotics/. There is also more great information in my book Fix Your Gut.

      • I have been using FloraStor/S. Boulardii after getting C. Diff induced colitis from a dental prescription and subsequent vancomycin use. Prescript-assist seems to be helping greatly but as you said it may be the initial phase. I took a quarter capsule initially with not much relief but took 1 whole pill since 4 days and it seems to help a lot. A relief after a long long time. But now a downer after I read your reports on HSO’s. Will your recommended probiotics above work in my case as well?

        • Since you are taking it and its is helping currently continue to take it for a week or two further and then ask your doctor about discontinuation.

  24. I use affiliate links but its for products I do believe in and recommend in the protocols in my book and on my blog. I have also coached people to use these supplements and I have used some of them myself.

    Have you thought about the use of a FODMAP diet for two months to shift his microbiome?

  25. John,

    I’m glad you’re writing about this. My son has autism (high functioning) and have been debating using HSO’s over and over. I want to help him – not put him at further risk.

    There seems to be an echo chamber in the paleo blogosphere and often times it’s for products and services that the bloggers are compensated for. I’ve seen it with HSO’s and then with RealDose fish oil etc. etc.

    Each of these have very generous affiliate programs – and there’s nothing wrong with affiliate links – I do pay per click and affiliate marketing too. These guys need to make a living –

    I just get a feeling in my gut (no pun intended) that some of these recommendations wouldn’t be there if compensation wasn’t involved.

    • I use affiliate links, but they are products that I have used and recommend to other people. I also list products that cannot be found on Amazon because I believe that they are the best. It is a necessary evil but I do not make recommendations based on compensation.

      • Good Article but I would need to see you debate someone much smarter than I or anyone else on this thread to believe your claims and get past the fact you are trying to sell a book that advocates against probiotics. Have you had such a debate with someone who knows the science and is pro Prescript Assist or any other probiotics? If so link on your site so we know the facts back you up and your argument holds up against people of equal intelligence on the subject. If you are proven right I will stand corrected and follow your protocol. I don’t mean to come of as rude but I am off the opinion you have to prove it among people who have the ability to call you out if there is incorrect info in your argument. The history on probiotics and millions of scientist so far say you are wrong. What makes you smarter or more of a qualified opinion than people who know more on the subject than you and do the psychical lab work rather than link sharing and opinion ranting?

        • Because not everyone agrees that HSO’s are safe ad some companies make them out to be, in fact in the studies that I listed many microbiologists have had such fears that I have shared in my writing to their use to improve digestive and overall health. Take that what you will but I have backed up a lot of my work in the multiple blog posts I have made about them on my website. Also, Hooper and I discussed at length about HSO probiotics on our live stream.

        • Hello Robert, right now the microbiome summit is going on and barely any of the speakers are talking up probiotics, it’s an unregulated industry, so John is right on, good for you John.
          I’ve taken some P.A., heard it was great for travelers diarrhea, found some reviews where airline employees were raving about it. I’ll probably finish up the bottle that I have but I will only take these things like once a week, if that.

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