What does Rhodiola rosea actually do, anyway?

Rhodiola rosea (henceforth, “rhodiola”) is a flowering herb whose roots have adaptogenic properties.

In the cold, mountainous regions of Europe and Asia where it grows, it has been used in herbal medicine for centuries to alleviate anxiety, fatigue, and depression.

What does the science say?

Well, let’s just say the science is more advanced than the traditional use:

❝In addition to its multiplex stress-protective activity, Rhodiola rosea extracts have recently demonstrated its anti-aging, anti-inflammation, immunostimulating, DNA repair and anti-cancer effects in different model systems❞

~ Li et al. (2017)

Nor is how it works a mystery, as the same paper explains:

❝Molecular mechanisms of Rhodiola rosea extracts’s action have been studied mainly along with one of its bioactive compounds, salidroside. Both Rhodiola rosea extracts and salidroside have contrasting molecular mechanisms on cancer and normal physiological functions.

For cancer, Rhodiola rosea extracts and salidroside inhibit the mTOR pathway and reduce angiogenesis through down-regulation of the expression of HIF-1α/HIF-2α.

For normal physiological functions, Rhodiola rosea extracts and salidroside activate the mTOR pathway, stimulate paracrine function and promote neovascularization by inhibiting PHD3 and stabilizing HIF-1α proteins in skeletal muscles❞

~ Ibid.

And, as for the question of “do the supplements work?”,

❝In contrast to many natural compounds, salidroside is water-soluble and highly bioavailable via oral administration❞

~ Ibid.

And as to how good it is:

❝Rhodiola rosea extracts and salidroside can impose cellular and systemic benefits similar to the effect of positive lifestyle interventions to normal physiological functions and for anti-cancer❞

~ Ibid.

Source: Rhodiola rosea: anti-stress, anti-aging, and immunostimulating properties for cancer chemoprevention

But that’s not all…

We can’t claim this as a research review if we only cite one paper (even if that paper has 144 citations of its own), and besides, it didn’t cover all the benefits yet!

Let’s first look at the science for the “traditional use” trio of benefits:

• Soothes anxiety
• Reduces fatigue
• Combats depression

When you read those, what are your first thoughts?

Please don’t just take our word for things! Reading even just the abstracts (summaries) at the top of papers is a very good habit to get into, if you don’t have time (or easy access) to read the full text.

Reading the abstracts is also a very good way to know whether to take the time to read the whole paper, or whether it’s better to skip onto a different one.

• Perhaps you noticed that the paper we cited for anxiety was quite a small study.
  • The fact is, while we found mountains of evidence for rhodiola’s anxiolytic (antianxiety) effects, they were all small and/or animal studies. So we picked a human study and went with it as illustrative.
• Perhaps you noticed that the paper we cited for fatigue pertained mostly to stress-related fatigue.
  • This, we think, is a feature not a bug. After all, most of us experience fatigue because of the general everything of life, not because we just ran a literal marathon.
• Perhaps you noticed that the paper we cited for depression said it didn’t work as well as sertraline (a very common pharmaceutical SSRI antidepressant).
  • But, it worked almost as well and it had far fewer adverse effects reported. Bear in mind, the side effects of antidepressants are the reason many people avoid them, or desist in taking them. So rhodiola working almost as well as sertraline for far fewer adverse effects, is quite a big deal!

Bonus features

Rhodiola also putatively offers protection against Alzheimer’s disease, Parkinson’s disease, and cerebrovascular disease in general:

Rosenroot (Rhodiola): Potential Applications in Aging-related Diseases

It may also be useful in the management of diabetes (types 1 and 2), but studies so far have only been animal studies, and/or in vitro studies. Here are two examples:

1. Antihyperglycemic action of rhodiola-aqeous extract in type 1 diabetic rats
2. Evaluation of Rhodiola crenulata and Rhodiola rosea for management of type 2 diabetes and hypertension

How much to take?

Dosages have varied a lot in studies. However, 120mg/day seems to cover most bases. It also depends on which of rhodiola’s 140 active compounds a particular benefit depends on, though salidroside and rosavin are the top performers.

Where to get it?

As ever, we don’t sell it (or anything else) but here’s an example product on Amazon.

Enjoy!

As “trending” health products go, castor oil is enjoying a lot of popularity presently, lauded as a life-changing miracle-worker, and social media is abuzz with advice to put it everywhere from your eyes to your vagina.

But:

• what things does science actually say it’s good for,
• what things lack evidence, and
• what things go into the category of “wow definitely do not do that”?

We don’t have the space to go into all of its proposed uses (there are simply far too many), but we’ll examine some common ones:

To heal/improve the skin barrier

Like most oils, it’s functional as a moisturizer. In particular, its high (90%!) ricinoleic fatty acid content does indeed make it good at that, and furthermore, has properties that can help reduce skin inflammation and promote wound healing:

Bioactive polymeric formulations for wound healing ← there isn’t a conveniently quotable summary we can just grab here, but you can see the data and results, from which we can conclude:

• formulations with ricinoleic acid (such as with castor oil) performed very well for topical anti-inflammatory purposes
• they avoided the unwanted side effects associated with some other contenders
• they consistently beat other preparations in the category of wound-healing

To support hair growth and scalp health

There is no evidence that it helps. We’d love to provide a citation for this, but it’s simply not there. There’s also no evidence that it doesn’t help. For whatever reason, despite its popularity, peer-reviewed science has simply not been done for this, or if it has, it wasn’t anywhere publicly accessible.

It’s possible that if a person is suffering hair loss specifically as a result of prostaglandin D2 levels, that ricinoleic acid will inhibit the PGD2, reversing the hair loss, but even this is hypothetical so far, as the science is currently only at the step before that:

In silico prediction of prostaglandin D2 synthase inhibitors from herbal constituents for the treatment of hair loss

However, due to some interesting chemistry, the combination of castor oil and warm water can result in acute (and irreversible) hair felting, in other words, the strands of hair suddenly glue together to become one mass which then has to be cut off:

“Castor Oil” – The Culprit of Acute Hair Felting

👆 this is a case study, which is generally considered a low standard of evidence (compared to high-quality Randomized Controlled Trials as the highest standard of evidence), but let’s just say, this writer (hi, it’s me) isn’t risking her butt-length hair on the off-chance, and doesn’t advise you to, either. There are other hair-oils out there; argan oil is great, coconut oil is totally fine too.

As a laxative

This time, there’s a lot of evidence, and it’s even approved for this purpose by the FDA, but it can be a bit too good, insofar as taking too much can result in diarrhea and uncomfortable cramping (the cramps are a feature not a bug; the mechanism of action is stimulatory, i.e. it gets the intestines squeezing, but again, it can result in doing that too much for comfort):

Castor Oil: FDA-Approved Indications

To soothe dry eyes

While putting oil in your eyes may seem dubious, this is another one where it actually works:

❝Castor oil is deemed safe and tolerable, with strong anti-microbial, anti-inflammatory, anti-nociceptive, analgesic, antioxidant, wound healing and vasoconstrictive properties.

These can supplement deficient physiological tear film lipids, enabling enhanced lipid spreading characteristics and reducing aqueous tear evaporation.

Studies reveal that castor oil applied topically to the ocular surface has a prolonged residence time, facilitating increased tear film lipid layer thickness, stability, improved ocular surface staining and symptoms.❞

Source: Therapeutic potential of castor oil in managing blepharitis, meibomian gland dysfunction and dry eye

Against candidiasis (thrush)

We couldn’t find science for (or against) castor oil’s use against vaginal candidiasis, but here’s a study that investigated its use against oral candidiasis:

Rosemary, Castor Oils, and Propolis Extract: Activity Against Candida Albicans and Alterations on Properties of Dental Acrylic Resins

…in which castor oil was the only preparation that didn’t work against the yeast.

Summary

We left a lot unsaid today (so many proposed uses, it feels like a shame to skip them), but in few words: it’s good for skin (including wound healing) and eyes; but we’d give it a miss for hair, candidiasis, and digestive disorders.

Want to try some?

We don’t sell it, but here for your convenience is an example product on Amazon 😎

Take care!