This page should be read in conjunction with The HDC experience.
Dosing with HDC
Once they have been ingested by a host, HDC will generally only survive for around 2 weeks, after which time they pass unnoticed out of the intestines. Doses therefore need to be taken approximately every fortnight, although some people may only need to re-dose every 3 or 4 weeks or, more rarely, every week.
One of the most common mistakes in determining an appropriate dosage for HDC is to think of it as a drug, making the assumption that one size fits every individual, and that age is the only possible variable.
Helminths in general are much more like physical exercise than a drug, and can be viewed as being literally “exercise” for the immune system. Just as with physical exercise, dosage needs to be optimised for each individual, and this needs to be done before one can begin to consider whether or not helminths might be working. Even once they are delivering benefits, optimisation continues to be an ongoing process.
Two forms of HDC are available: fresh and commercially prepared.
Fresh HDC have slightly greater efficacy than commercially prepared HDC, but this is fully compensated for by taking slightly more of the latter - a fact reflected in the dosing recommendations for each type set out below.
Fresh HDC, however, have a much shorter shelf life than commercially prepared HDC, and will not survive for more than 48 hours after being harvested. So fresh HDC should be used within 24 hours of harvesting, not 24 hours after receipt by the user. For more detail about this, see Storage and survival of HDC, below.
Dosing with fresh HDC
Fresh HDC are those that have been self-grown or obtained from a local source immediately following extraction from the intermediate host (usually a beetle). They have not been cleaned in any way nor placed in a nutrient solution for longer term storage and shipping.
Typical dosage with fresh HDC
|Typical initial dose||Typical “optimised dosage”||High “optimised dosage”|
|Adults||5-30 HDC every 3 weeks||20-30 HDC every 3 weeks||100 HDC every week|
|Children||1-10 HDC every 3 weeks||5-10 HDC every 3 weeks||10-20 HDC every week|
Optimising the dosage with fresh HDC
This decision tree for determining the optimal size and frequency of dosing with fresh HDC is taken from this paper.
Someone who is hypersensitive would be advised to start with even less than 5 HDC.
Dosing with commercially prepared HDC
Commercially produced HDC are cleaned using antibiotics and placed in a nutrient solution for longer term storage and shipping - for example those sold by Biome Restoration. Due to their processing, commercially prepared HDC may have approximately 30-50% less therapeutic activity than fresh HDC, which is the reason for the 50-100% increase in the doses recommended for the commercially prepared product in comparison with the fresh product.
Typical dosage with commercial HDC
The following table shows numbers that are roughly 50% - 100% greater than those required when using fresh HDC.
|Typical initial dose||Typical “optimised dosage”||High “optimised dosage”|
|Adults||5-15 HDC every 2 weeks||30-60 HDC every 2 weeks||200 HDC every week|
|Children||2-10 HDC every 3 weeks||10-20 HDC every 3 weeks||15-30 HDC every week|
Optimising the dosage with commercial HDC
1. Start with a low dose.
It can be counterproductive to start with larger doses In the hope of getting results more quickly.I started with 60 HDC every two weeks 13 weeks ago. I felt awful for weeks and months -- brain fog, fatigue, bad mood -- since week 4. Just this week I went down to 30 and feel so much better. It is very clear to me that I was suffering for no good reason, trying to be brave and get the benefits sooner. Silly.  Length of time is as key as dose, so really using a very tolerable dose for longer is a much better idea than speed and higher doses. 
See The HDC experience for further examples of possible side effects.
There is no harm in starting with even lower doses than those shown in the table above, and doing this will further reduce the chance of encountering side effects in the first few weeks.
Some adults who tend to be very sensitive to supplements and medicines have found that 10 commercial HDC was a manageable starting dose, but some have found that even 10 was too much for them, and one individual even reacted badly to an initial dose of 5.I had a really really bad reaction. But I'm not sure why… I would always start with the lowest dose possible, just in case.
2. Increase the dose gradually until either mild and temporary diarrhea is observed, or until full relief of symptoms is obtained.
The size of subsequent doses is typically increased gradually over two months to 30-60 HDC taken every 2 or 3 weeks, which is the dosage with which most users report the best results. However, some people may be unable to proceed at this speed, and one HDC user believes that she does best on just 5 HDC every 2 weeks.After trying 5, 10, 20, and 30 I finally have to admit I did best with 5. I was determined to keep going up, but benefits seem to have diminished with every increase.
This user’s very detailed report of her first 3 months with HDC is presented here.
A child who had a positive response to an initial dose of 5 HDC, but who was then given 10 HDC three weeks later, reacted to this doubling of the second dose by becoming angry and aggressive for a week, and also vomiting. 
One person with CFS/ME who started with 5 commercial HDC every 2 weeks needed 6 months to gradually build up to 30 every 2 weeks.
3. Vary the interval between doses according to individual needs.
Instead of taking 30 HDC every 3 weeks, it may be better to take 20 every 2 weeks, or 10 every week. Dosing more frequently with commensurately fewer HDC produces the same therapeutic effect as taking a larger dose less often. It also helps to smooth out any fluctuations in benefit, and helps to reduce the chance of an adverse reaction in the early stages of the therapy.
In some people, the beneficial effects of a dose of HDC may only last for 2 weeks.I just recently switched my hdc subscription scheduling from 3 weeks to 2. I definitely could feel the fatigue start to return after 2 weeks. 
Some self-treaters may even need to take a dose as often as every week.... after about a week and a half I really need that next dose. I've fussed with dosage a lot and come up with weekly doses of 30. I seem to go off a cliff after 10 days and this gives me some reserve if a shipment is late. Every time I dose again (taking 30 HDC every 2 weeks) there's a cycle. For a few days I feel fantastic (that's the right word!), energetic, perfect digestion and mental clarity. And then there's a few days of the opposite. I can't think straight, no matter what I eat (allergen free) I have digestive troubles. I've been experimenting with this for the last 9 months. I have tried as high as 40 HDC, but am currently doing 10 HDC every week. In my case, 10 seems to distract my immune system, but 40 seems to kick it into high gear. 
4. If mild diarrhea is experienced before full symptom relief is obtained, then the dosage is lowered and the frequency of administration is increased.
5. After a honeymoon period of between 6 months and a year, further dosage increases may be needed to maintain full symptom relief.
6. The dosage must be re-optimised periodically in the long-term.
7. While a few people may need to continue to use smaller doses in the long-term, this approach is inadequate for many people, and, when one provider offered their customers the chance to experiment with higher doses of HDC at no extra cost, 91% of those who took up the offer decided to maintain the higher dose thereafter, as a result of them having experienced increased efficacy.
HDC are taken in a drink, along with a little fat. This stimulates the release of bile into the gut, and the bile activates the HDC. Only a small amount of fat is required, and it doesn’t matter what food this comes from. Even a single fish oil capsule will be sufficient. Apart from taking some form of fat with each HDC dose, there is no other requirement, and there is no reason to take an antacid before HDC.
Anyone who needs to take the bile acid sequestrant drug, cholestyramine (CSM) - also known as colestyramine, and sold as Questran, Questran Light, Cholybar and Olestyr - should avoid taking a dose of the drug before they take HDC. If the morning dose of CSM is omitted, and the HDC are taken before breakfast, the fat contained in this meal will trigger bile release in the small intestine, where the HDC will hatch after they leave the stomach, usually within 2 hours of being taken. This is the only time at which CSM needs to be avoided, so only a single dose will be missed every few weeks.
For a list of supplements and medications that may adversely affect HDC, see this page. (Scroll down the page to locate the section.)
Side effects and adverse reactions to HDC
Side effects are commonly experienced during the first few days. For more detail, see the following page section.
The following comment about adverse reactions is from researchers working in the William Parker lab.
When mild side effects, such as an increase in hyperactivity in children, occur in the early stages of the therapy, these can be treated with an antihistamine or ibuprofen, but not paracetamol (acetaminophen) . Alternatively, the size of the dose can be reduced until the side effects pass, which they invariably do eventually.
Diarrhoea can be treated with loperamide (Immodium, Lopex, etc.).
Many of the side effects that can follow helminth inoculation manifest in a similar way whichever species is being hosted and can mostly be treated using the same strategies, many of which are detailed on the following page for self-treaters hosting NA.
If termination were to become necessary, for example due to colonisation in a child (see Risk of HD maturation and persistence), the appropriate treatment is described on the following webpage.
- Centers for Disease Control and Prevention: Hymenolepiasis (Click on the “Treatment Information” tab.)
Response to HDC
Some people expect HDC to perform in the same way as a drug and start to deliver benefits within days but, while a significant proportion of people using HDC do indeed begin to notice positive changes after only days or weeks, these might not become consistent until after 3 months, which is how long helminths in general take to begin to provide consistent benefits.
In some individuals, HDC may take much longer than 3 months before producing results, so users should continue to take them for a minimum of 6 months before deciding whether or not they are likely to help. In a few cases, helminthic therapy self-treaters, including those taking HDC, may not see any obvious benefit from the therapy for up to 2 years.
A naturopathic doctor has reported that, although a lot of her IBD clients are symptom free after only 4 doses of HDC, it usually takes around 24 weeks before her clients' food intolerances and energy show significant improvement.  It is also possible for helminthic therapy self-treaters to experience periodic exacerbations of their diseases up to 18 months after taking the first dose, even after benefits have begun to appear.
"Fresh" HDC are available from the HDC providers listed on the Helminth providers page (use the search function on your device [Control+F on a PC, or Command+F on a Mac] to search the page for "HDC") and from a number of naturopathic doctors in the US. "Commercially prepared" HDC are supplied by Biome Restoration.
For details of the differences between the two types of HDC, and to avoid falling victim to the hype that is advanced by some suppliers of the "fresh" variety, see Storage and survival of HDC above, and Doctors as providers.
Storage and survival of HDC
HDC experience a gradual and continuous decline from the moment they are extracted from their intermediate (beetle) host and, even if they are placed in a saline solution, only 60% will survive for 24 hours, and none for more than 48 hours. Therefore, doses of fresh HDC should be taken as soon as possible, ideally immediately after extraction, but definitely within 24 hours of being harvested - not 24 hours after receipt by a customer.
The commercially prepared HDC supplied by Biome Restoration will survive for 2 to 3 weeks as a result of being stored in a nutrient solution developed specially for this species by this company. HDC from this source are usually received within 11 days of being shipped, and must then be used immediately or refrigerated for up to 2 weeks at 4ºC (39-40ºF). There is anecdotal evidence that a shorter storage period is likely to result in a better immune response to the HDC.
HDC are unlikely to be harmed by extremes of temperature encountered during shipping. Hymenolepis diminuta thrives in cold conditions, and while they can be killed by temperatures that are sufficiently low to cause the liquid containing them to freeze, the shipping solution used by Biome Restoration has a very low freezing point, so would need to be exposed to temperatures as low as -18ºC (0ºF) for several hours before it would freeze. Therefore, in practice, even commercially prepared HDC that are shipped in the winter to countries such as Canada are unlikely to be damaged by the cold. In fact, the survival time for these HDC increases with lower temperatures.
HDC are also unlikely to be harmed by heat during shipping, even when shipped to very hot countries. Mature HD live in rodents with a body temperature of 37ºC (99ºF), so are accustomed to heat. Only temperatures approaching 50ºC (122ºF), or higher, will start to have a noticeable effect on the longevity of the HDC, and several days at these very high temperatures would be required before their lifespan would be affected.
Where do HDC live in humans?
After ingestion, HDC settle in the small intestine and attach to the intestine wall by means of suckers on their scolex,  but they do not form lesions at the site of attachment since they have no mechanism by which to breach the epithelium. They effectively “swim” in the fecal stream within the intestine. 
When found in its natural host (the rat) the adult HD occupies most of the larger animal's small intestine, maintaining this position by monitoring information from sensors in its head and tail.  No one knows for certain where HD might prefer to settle in the much larger intestine of a human host, but expert opinon has suggested that the lower third of the human small intestine - the ileum - would appear to be this worm's most likely preference.
There are no reports in the scientific literature of H. diminuta mis-migrating to other organs in humans.
For details about how long H. diminuta survive in humans, see Risk of HD maturation and persistence.
Caring for HDC
While Hymenolepis diminuta is a robust organism, there are a few substances that can reduce its beneficial effects, and those that are known to do this, or may have a potential to do this, are listed below. Items marked with a ✅ are things about which HDC users have expressed concern, but which are actually unlikely to have any adverse effect on this organism.
Anything not listed below is likely to be harmless to HDC.
The medication most commonly used to terminate a Hymenolepis colony is Praziquantel (Biltricide etc.). Also used for this purpose are Niclosamide (Niclocide, Fenasal, Phenasal, etc.) and Nitazoxanide (Alinia, Nizonide, etc.).
Other drugs with anthelmintic properties that may also have an adverse effect on HD include the following.
Abamectin, Albendazole, Aminoacetonitrile derivatives, Arecoline, Artemisinin (Artemisinine, qinghaosu), Bephenium hydroxynaphthoate (Alcopara, Alcopar, Befenium, Debefenium, Francin and Nemex), Diethylcarbamazine (DEC, Hetrazan, Carbilazine, Caricide, Cypip, Ethodryl, Notézine, Spatonin, Filaribits, Banocide Forte and Eofil), Fenbendazole, Flubendazole (Flutelmium), Ivermectin (Stromectol, Soolantra, Sklice, etc.), Levamisole (Ergamisol), Mebendazole (MBZ, Vermox), Metronidazole (Flagyl), Monepantel (aminoacetonitrile class), Octadepsipeptides (e.g. Emodepside), Oxamniquine (e.g., Vansil), Oxyclozanide, paraherquamides, Piperazine and its many derivatives, Pyrantel pamoate (Pin-X, Combantrin, etc.), Salicylanilide, Spiroindoles (e.g. derquantel), Tiabendazole (thiabendazole, TBZ, Mintezol, Tresaderm, Arbotect, etc.) Triclabendazole (Fasinex, Egaten, etc.).
- Azithromycin Someone who took a 5 day course of azithromycin found that this diminished all the benefits he had gained from HDC (e.g., his brain fog and mood “went back to bad”) and this loss of benefits continued for 6-8 weeks, even though he took a dose of 30 HDC 2 days after the course of antibiotic was completed, and continued to take HDC fortnightly thereafter. 
- Dapsone (also known as diamino-diphenyl sulfone or DDS) is an antibacterial used primarily in the treatment of leprosy. One HDC user reported that they take 50mg of Dapsone daily, but stopped taking this when they began HDC. When, a few days later, they resumed the Dapsone, their disease symptoms returned. Someone else, who was taking dapsone for vasculitis, but stopped taking it when he began using HDC, found that the “good times” ceased when he went back on the dapsone, so decided to alternate the drug and HDC.
- Cholestyramine (CSM) (also known as colestyramine, and sold as Questran, Questran Light, Cholybar and Olestyr). Since HDC require bile to trigger hatching, this bile acid sequestrant drug should be avoided immediately before a dose of HDC is taken. If the morning dose of CSM is omitted, and the HDC are taken before breakfast, the fat contained in this meal will trigger bile release in the small intestine, where the HDC will hatch after they leave the stomach, usually within 2 hours of being taken. This is the only time at which CSM needs to be avoided, so only a single dose will be missed every few weeks.
- Escitalopram (Cipralex and Lexapro.) After taking "the smallest possible dose" of this selective serotonin reuptake inhibitor (SSRI) in the form of Lexapro for 4 weeks, one user found that she lost all the benefits previously conferred by NA, and reported that even HDC benefits were dampened. .
- Acorus calamus (also known as sweet flag, sway or muskrat root, etc.) The bitter element in sweetflag, acorin, is claimed to have anthelmintic properties, and the standardised rhizome extract of A. calamus has been shown to have significant dose-dependent effects against Hymenolepis diminuta. 
- Croton joufra. The leaves of Croton joufra have been used traditionally in Assam (Northeast India) to treat intestinal helminthic infections, and its leaf extract possesses significant anthelmintic efficacy, as demonstrated in one study using Hymenolepis diminuta. 
- Oroxylum indicum (also known as broken bones plant, Indian calosanthes, Indian trumpet flower, kampong, midnight horror and tree of Damocles). The bark extract of O. indicum produces concentration-dependent effects against both larval and adult H. diminuta. 
- Senna. Extracts of Senna alexandrina and other Senna plant species have been found repeatedly to have anthelmintic effects against Hymenolepis diminuta      as well as other parasites. 
- Lactobacilli and bifidobacteria. Socio-medical researchers associated with the William Parker lab have reported that a supplier of HDC has expressed confidence that one or both of these milk-based probiotics can interfere with the beneficial systemic, but not the GI, effects of HDC. Two HDC users have reported losing the benefits from their HDC after taking Lactobacilllus reuteri, one of them describing the effect as follows:
- Lactobacili Reuteri killed my HDC. The effect was quick. And it took me 3 weeks to realize why I was getting worse. Several weeks to feel better too. 
However, other HDC hosts have not noticed any adverse effect on their colony as a result of using probiotics.
- Probiotics did not affect my HDC, when I was hosting. 
- ✅ Kefir. While this fermented milk drink contains lactobacillus species, one HDC user has said that she was not aware of any adverse effects on her worms while eating raw kefir purchased from a store.
- ✅ Saccharomyces boulardii can have an adverse effect on the dog roundworm, Toxocara canis,  but Duke researchers have established that neither this tropical yeast, nor ✅ soil-based probiotic organisms are a threat to HDC. And ✅ Dr. Ohhira's Probiotics Original Formula appears not to interfere with HDC's beneficial effects.
- Detoxification / chelation
- ✅ Fasting
At one time, it was thought that fasting would harm HDCs by depriving them of carbohydrate, but this appears to be unlikely because these organisms can live off glycoproteins secreted by the gut.
- ✅ Hot beverages
It is best not to take HDC with a very hot drink, but, once the HDC have been swallowed, they are unlikely to be affected by hot beverages because these will be closer to body temperature by the time they reach the stomach. 
It is relatively easy to culture HDC at home. For incubation instructions and details of the necessary equipment and supplies, see the following page.
- The HDC experience
- The safety of self-treatment with HDC
- HDC compared with the other therapeutic helminths
- Personal stories from users of HDC and other helminth species. Use the search function on your device (Control+F on a PC, or Command+F on a Mac) to search the page for "HDC".
- The Tapeworm Hymenolepis diminuta as an Important Model Organism in the Experimental Parasitology of the 21st Century -- Full text | PDF
- Production and Use of Hymenolepis diminuta Cysticercoids as Anti-Inflammatory Therapeutics