The corresponding article on the Benefits of Tribulus has given us a lot of interesting information. While the preponderance of evidence showed that Tribulus was safe, there were some outlying cases and studies that I felt I needed to bring to my readers’ attention.
In addition to side effects, there are also other factors to keep in mind, such as other prescriptions you’re taking. Be sure to read every section if you’re considering taking Tribulus. And now without further ado, here’s all the scientific community has to say about the adverse effects of Tribulus Terrestris.
What You Need to Know
Symptoms
The following are almost completely from case study literature. This means that the data weren’t reported during clinical trials, but from patients coming to a hospital or doctor with symptoms, symptoms the attending physicians later determined to be the result of Tribulus use.
Kidney & Liver
We do have one, albeit older, case of a young man taking Tribulus Terrestris and it resulting in toxicity of the Kidney and Liver. The effects were bad enough to cause a kidney stone, but we don’t know how much he had taken or for how long. Another case from much more recently showed the build up of several foreign substances in a young man's kidneys. Again, however, we don’t know any details about his Tribulus use. This doesn’t tell us a lot, but it’s something to keep in mind.
GI Irritation/Cramps/Diarrhea
In one of the few clinical trials reporting side effects, we actually have quite a few listed, but all having to do with digestion. It should be noted that the dose in this experiment was quite low (7.5 mg), while other trials with much higher doses had no side effects.
Lung (fruit)
I’ve read that there is a risk from eating the spiny fruit of the Tribulus itself, and I finally tracked down the reason for the warning: an isolated instance from 20 years ago, where in an adolescent had eaten one of the thorns from the plant, which then lodged in his bronchial tube; I would recommend processing this part of the plant, or simply avoiding it.
Priapism
While often joked about, it’s really no laughing matter. In fact, one man had to receive medical attention due to his prolonged erection, and it required an invasive procedure.
Gynecomastia
This again comes to us from one isolated instance, but we report what we find, here at the Great Green Wall. In this case, it appears a young man had breast tissue growth as a result of taking Tribulus, though we don’t know how much he took–or if he was taking something else as well.
IMPORTANT – Blood Sugar (Pre-Op)
In the article corresponding to this one, I noted that several clinical trials have shown Tribulus can lower blood sugar. While generally a good thing, you need to let medical staff know if you’re receiving surgery. Not doing so could be fatal.
Breastfeeding
We don’t have a lot of data on humans, but what information we do have is a tad alarming. For instance, one case study of an ovine population showed brain disorders in the young of ewes who consumed Tribulus.
Interactions with Medications
In addition to the effects of simply using too much Tribulus, there are also medication considerations. Please read this section carefully, as some of the consequence can be serious.
Diuretics
Several hospitals warn that Tribulus can increase the effect of diuretics, which may lower your blood pressure to a dangerous level. If you’re taking diuretics, don’t start taking Tribulus before speaking to your doctor; and if you’re taking Tribulus, tell your physician if they want to put you on diuretics.
Blood Pressure Meds/Thinners
Because Tribulus can lower blood pressure on its own, you need to let your doctor know if you’re taking both, or may take both at any point in the future.
Antidiabetics
Similar to the above two medication types, you don’t want to take an herbal remedy for something which your prescription addresses as well. Given the blood-sugar effects of Tribulus, you definitely want to consult your doctor about a possible interaction with diabetic medications.
Lithium
Though not commonly prescribed anymore, Lithium is still used in tightly controlled situations. Indications are that Tribulus could prevent your body from passing Lithium out of your system, resulting in dangerous toxicity.
Final Thoughts
Many of the safety issues related to Tribulus center around young men taking it for steroidal effects. For the rest of us, especially those not currently on medication, the recommended doses of 750-1500 mg at 90 Day intervals seem to be well-tolerated. If you feel you may be having an adverse reaction, though, be on the safe side and consult medical help.