A customer asks, “Is beta sitosterol toxic to mens testosterone. Is it estrogenic. Is it bad for men’s sexual health?”
Beta-sitosterol, more often written as β-sitosterol, is a phytosterol, which essentially means plant steroid, similar in structure to cholesterol. You can notice the word -sterol in both of these, and can see the structural similarity between these and various other hormones..
More specifically, it does appear to be a phyto-estrogen, which is why this person posed this question. Research shows it is “weakly estrogenic”.
This question is right in alignment with what I recently wrote on Are Phytoestrogens Dangerous or Healthy?
Herbs and Foods that contain Beta-Sitosterol
Some herbs that contain beta-sitosterol, including several available here at Lost Empire:
- Pine Pollen
- Dong Quai
- Saw Palmetto
- Goji Berries
- Nettle Root
There likely are many, many more, but it was hard to come across a complete list anywhere.
According to some research Pine Pollen contains beta-sitosterol. So this fairly clearly drives the point home. Should men avoid Pine Pollen because it contains this phyto-estrogen? Clearly not. Clearly the phyto-androgens are stronger in their actions.
And it’s not just herbs. You’re actually likely to get far more of this compound from foods containing beta-sitosterol. Here are some of the top foods rich in this compound:
- Vegetable oils (corn, canola, soy and flax)
The top of the list was corn oil with 621mg per 100g serving.
The Benefits of Beta-Sitosterol
Just a quick look through Pubmed revealed a review, titled An update on β-sitosterol: A potential herbal nutraceutical for diabetic management, had this wide-ranging statement to me on the compound:
“It has been evidenced in many in-vitro and in-vivo studies that [beta-sitosterol] possesses various biological actions such as anxiolytic & sedative effects, analgesic, immunomodulatory, antimicrobial, anticancer, anti – inflammatory, lipid lowering effect, hepatoprotective, protective effect against NAFLD and respiratory diseases, wound healing effect, antioxidant and anti-diabetic activities.”
That makes it sound pretty miraculous indeed!
Mostly, the area of BPH and prostate cancer stated have been studied. One study found, “Beta-sitosterol is a sterol able to improve urinary symptoms and flow measures, but not to reduce the size of the prostate gland.”
This is a compound that is rich in Saw Palmetto, one herb that has widely been used for these functions. The research (such as this study) points to, as well as many anecdotal stories, that it works.
Yet this picture is complicated by the fact that this study found beta-sitosterol content ranged from 0.1 to 32.55 mg/g across different saw palmetto supplements. And this is just one compound of many found in such herbs.
When something is weakly estrogenic that means it has weak binding-affinity to estrogen receptors in the body. In some cases this can displace human estrogens, as well as the more harmful xeno-estrogens. In other words, weakly estrogenic can sometimes be helpful to the function of your endocrine system. Some of it’s beneficial effects on prostate healthy likely come from this action.
The Drawbacks of Beta-Sitosterol
Studies have looked at endocrine disrupting effects of beta-sitosterol in fish.
“In this study, the effects of beta-sitosterol, a phytoestrogen present in high concentration in bleached kraft pulp mill effluent (BKME), on reproductive fitness of goldfish were investigated.”
So this is dealing with essentially industrial waste, which happens to have this compound!
“Plasma reproductive hormone levels were measured in male and female goldfish on Day 4 following two intraperitoneal injections of beta-sitosterol or an oxidized sitosterol preparation.”
And then they inject the compound into the fish because that’s the natural route of administration of course! Ah science, the crazy things you do in the pursuit of knowledge.
The male fish saw lower testosterone levels. The female fish saw lower testosterone and estradiol levels.
But another fish study saw less change but in a different fish species.
What does this mean for you? Not much. In my estimation, injections of fish really doesn’t pertain to you much at all.
Turning to another possibility, as discussed in this article on the prostate, some people do have negative effects such as ED when taking saw palmetto. With a leap and a jump, some may blame the beta-sitosterol for that function. It could certainly play a role, but is hardly conclusive evidence.
Conclusions on Beta-Sitosterol
So you see that this compound, despite being a phyto-estrogen, can be found in many herbs that are well known for supporting male sexual and reproductive health.
It is even more widely available in foods, because it is a natural compound widely used by nature in plants.
This does not mean you should go and guzzle corn or canola oil though!
All things in moderation. Beta-sitosterol, being a common plant sterol found throughout nature, can have many beneficial effects because it impacts many systems, such as cholesterol does in the human body.
But if you’re concentrating it, as found in some supplements, there is opportunity for things to go wrong.
Plus remember this is a reductive lens to look at things. These herbs are not a single compound. That is not how they work. While reductive science tries to find the molecules responsible for cause and effect, the complexity of biology doesn’t actually work quite like that.
No amount of injecting effluent into fish will give us all the answers.
The verdict: Beta-sitosterol is a beneficial and common compound. Like most things there may be cases or amounts where there is too much.
The wider verdict that all phyto-estrogens must be avoided is demonstrably false.