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Micro-dosing berberine: good idea? bad idea?

Berberine Supplement

I’ve been “micro-dosing” berberine, usually around 150-200mg a day for a few days. The smaller dose (most supplements come in 500mg pills) came after I experienced side effects from higher doses. My main focus is on gut repair, but I’ve stumbled across some research, and pieced together a few themes that had been rattling around in my mind, that point towards berberine supplementation as an anti-cancer strategy, which it may be, but as we’ll see it’s dependent on dose.

See also: a systematic review of the anticancer properties of berberine

And we’re going to get to berberine in just a minute, I promise.

But first some contextual housekeeping to set the stage.

The dangers of glucose?

I’m now more of a plant based guy, but on my long and winding health journey, I started on the ketosis / paleo side, mainly because there are some very compelling authors /commentators on that side of the fence.

For example, Tim Ferriss has had a number of guests on his podcast who I think highly of, such as Dr. Peter Attia and Dr. Dom D’Agostino being two examples. To oversimplify, I think it’s fair to say that both these gentlemen, and Tim himself, seem to be in the “glucose is bad” camp. They try to limit eating high glycemic foods.

Why is glucose thought to be problematic?

Glucose, Insulin, IGF-1, then mTOR

Glucose, and of course sucrose as well, causes inflammatory spikes in insulin and also acts to feed cancer cells. Both normal cells, and cancer cells feed at the same trough, or so the thinking goes. The Mayo Clinic has publicly debunked this theory as a “cancer myth,” but it seems to be at the heart of the ketogenic philosophy. (R) From where I am sitting, the jury seems to still be out.

Enter Metformin, a popular diabetes drug that lowers blood sugar and blood cholesterol, and that has also shown promise in reducing the risk for certain types of cancers. (R)

To quote an article in the Annals of Translational Medicine, discussing Metformin’s use in Cancer Therapy:

It is believed that systemic effect of metformin manifested by the reduction of circulating level of insulin and insulin-like growth factor 1 (IGF-1) might be associated with anticancer action (13). Insulin/IGF-1 is involved not only in regulation of glucose uptake but also in carcinogenesis through upregulation of insulin/IGF receptor signaling pathway (14). The excessive food consumption (insulin) leads to increased liver production of IGF-1 that binds to IGF-1 receptor and insulin receptor. Then, through insulin receptor substrate (IRS) the signal is transmitted to phosphoinositide 3-kinase (PI3K), and Akt/protein kinase B (PKB) that indirectly activates (not phosphorylates) mTORC1.

Prophylactic use of metformin

According to Ferriss, Silicon Valley executives have been taking metformin, as a prophylactic measure for cancer prevention and as a longevity strategy.


Metformin has been shown to inhibit the mTOR pathway, which “plays a pivotal role in metabolism, growth and proliferation of cancer cell.” (R) Metformin use has been associated with decreased risk for several types of cancers. (R) I refer you back to the quote above from the Annals of Tranlational Medicine, and ask whether metformin’s reduction in cancer risk is evidence that glucose levels do indeed play a role in cancer growth? Idea being that limiting large spikes of insulin limits IGF-1 and then mTOR.

Enter Berberine

Berberine is a natural alkaloid compound long used in traditional Chinese and Aryuvedic medicine. When taken orally, berberine has a hypoglycemic effect in that it lowers blood sugar. (R) In fact, studies show that berberine is just as effective at treating type 2 diabetes as metformin and that it also inhibits the mTOR pathway. (R) (R)

Why then wouldn’t berberine act as a buffer against the spiking insulin levels that increase circulating levels of IGF-1 and eventually mTOR? Why isn’t everyone taking a little berberine everyday, especially with high glycemic meals?

There are four answers:

  1. As far as cancer is concerned, berberine behaves very differently depending on the dose administered
  2. Most people haven’t heard of berberine
  3. Berberine carries with it some unpleasant side effects
  4. Berberine use must be cycled or it taxes the liver

With berberine, the devil is in the dose

I will get to the liver and side effects in a moment, but the behavior of berberine at different doses is of interest here because we’re discussing micro-dosing and I decided to take smaller than recommended doses in the first place to get around those side effects.

When truly micro dosed, at very small levels, this peer reviewed study found that berberine actually encouraged the growth of cancer cells and interfered with cancer drug therapies:

Our results demonstrated that berberine at low dose range (1.25 ~ 5 μM) promoted cell proliferation to 112% ~170% of the untreated control in various cancer cells, while berberine at high dose rage (10 ~ 80 μM) inhibited cell proliferation. Further, we observed that co-treatment with low dose berberine could significantly attenuate the anticancer activity of chemotherapeutic agents, including fluorouracil (5-FU), camptothecin (CPT), and paclitaxel (TAX).

These findings are known as hormesis, the situation where a low dose can cause adaptation, where a higher dose is destructive. I believe this is the same concept associated with antibiotics, and why people are encouraged to finish all of a prescription. The bugs not killed by the lower dose will now become resistant to the therapy.

Question becomes, what does a dose that has anti-cancer effect look like in milligrams? 1.25 – 5μM is between 0.42 – 1.68mg of berberine, which is a very very low dose. My “micro-dosed” regimen at 200mg was far higher than the amount shown to encourage cancer growth and diminish activity of cancer medications.

Score one for taking berberine every so often.

However, there are side effects.

Side effects and cycling use

Since I had been having side effects from higher dose berberine at 500 -1,000mg a day, I assumed I could scale back and get the same or similar benefit.  I reasoned that the dose recommendations from manufacturers were aimed at getting customers to use more of a product, rather than being tied to efficacy. For some people, lower doses may be the way to go, although the studies on diabetes dosed at 500mg a few times a day.

Berberine is a plant compound, and alkaloid. What is the definition of an alkaloid?

According to Google an alkaloid is:

any of a class of nitrogenous organic compounds of plant origin that have pronounced physiological actions on humans. They include many drugs (morphine, quinine) and poisons (atropine, strychnine).

Pronounced physiological actions.

Berberine is a plant, but acts like a drug. It will lower blood sugar and can cause dizziness. Some commentators online have said that berberine will only lower blood sugar if elevated, making it a normoglycemic, but I haven’t seen evidence for this in my research – please share in the comments if you have a good source.

Another common berberine complaint with higher doses of berberine is upset stomach, which is part of the reason I was taking smaller doses.

Berberine should not be taken indefinitely

Berberine is not a supplement you should buy on subscription as long term use could harm the liver. (R) It’s better used in cycles of 6-8 weeks, with nice long break periods in between.


Although the anticancer efficacy is obviously unclear, it appears that occasional 6-8 week courses of berberine between 100-1,000mg a day are safe.  In addition to preventing spikes in blood sugar, using berberine in this way could also prove beneficial to heart health and digestive health.

I plan to use berberine for maintaining gut health and occasionally as a hedge against very high glycemic meals.

See also: Is curcumin proven by human studies?

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  1. Kathart says:

    I was taking Berberine glucose mgmt HCI 400mg 1x daily and had subsequent intestinal distress so bad I couldn’t leave my house. It did reduce my blood glucose levels quite well. But I had to stop. I still need to take it to help with elevated glucose but need to take as you describe. I also could not take metformin for same reason, only more intense and longer lasting.

    So are you saying you would take only intermittent when you had a “cheat” meal or only for a couple of weeks at a time? What does that do to your blood glucose overall when start and stop is used? Also I’ve been unable to find it at lower than 400mg dose

    • Well, I see berberine as a supplement to “cycle” every so often, not for everyday use for months, years. Yes, I will go on a berberine cycle for a few weeks and empty 1/3 – 1/2 of a 500mg pill and take that, usually when I eat a higher glycemic meal (oatmeal with banana for example). My concern is that my blood sugar is normal and I don’t want to crash it. I haven’t measured my blood glucose levels while taking berberine. Anytime I have played around with a blood glucose monitor, it’s been such a pain in the ass I inevitably stop.

      As far as dosing is concerned, I feel most supplement dosing is arbitrary at best, we all have to figure out what works best for each of us. Based on my research, even a dose of 200mg would put you well above the hormesis levels described in the study I cite, but it’s obviously something to discuss with your doctor. Thanks for reading and thanks for the comment.

  2. ILene says:

    I’m taking Berberine 500mg twice a day for 2 months to lower my cholesterol….my total number dropped 60 points and my LDL went from 147 to 98!!! I initially had some stomach upset, but now it seems much better. Question: Do I need to stop taking Berberine for 2-3 weeks??? or longer???…and if so would it be as if I’m starting up again (ie. stomach upset)?
    My friend has been taking Berberine for 4 years without stopping and her Integrative Doc says it’s ok. Very Confused on dosing….have any answers? Thank you so much…..

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