|We still need human studies to confirm the results of the studies to call maca and garcinia cola "proven T-boosters"!|
With that being said, there's a second thing I must say right away: both studies I will discuss in today's article are rodent studies (rats to be specific) and need confirmation in humans - follow up studies that confirm the >100% increase in testosterone with really high doses of MACA extracts and >300% increase in response to high dose garcinia cola supplementation.
Whut? No, those are no typos. The treatments did in fact more than double the total testosterone concentrations of the rodents in the studies from the Graduate School of Life and Environmental Sciences of the Osaka Prefecture University (Ohta. 2016) and Walter Sisulu University in South Africa (Sewani-Rusike. 2016).
- MACA - Lepidium meyenii (maca) is a plant growing in Peru’s central Andes, of which you've certainly heard that it has traditionally been used for enhancing fertility and reproductive performance in domestic animals and human beings.
In their latest study, scientists from the Graduate School of Life and Environmental Sciences of the Osaka Prefecture University (Ohta. 2016) examined whether feeding a hydroalcoholic extract powder of maca for 6 weeks would affect the weight of the reproductive organs, serum concentrations of testosterone and luteinising hormone (LH), number and cytoplasmic area of immunohistochemically stained Leydig cells, and steroidogenesis of cultured Leydig cells in 8-week-old male rats.
Figure 1: Effects of feeding maca extract on serum testosterone and LH concentrations in male rats (Ohta. 2016).
The best news is that this happened in the absence of increases of prostate gland weight, and without increases in serum LH concentration that would suggest that the leading cells, the number of which didn't increase either, wouldn't produce T as effectively, any longer. This also implies that the provision of what would be ~12g of MACA per day (2% of the diet were a proprietary MACA extract called MACAXS™ | no sponsorship or support declared) increased the testosterone production by Leydig cells significantly - a result and mechanism the scientists were able to confirm in vitro.
But isn't there human data, already, which refutes these results? To my knowledge the answer to this question is "NO". Not because there were no studies on the effects of maca, for example, on libido and testosterone, but rather because these studies used, just like a study by Gonzales, et al. from 2002 doses that were not just >5x lower than the human equivalent in the study at hand, but also based on regular gelatinized maca powder, instead of an extract, as it was used by Ohta, et al. Against that background it is, by the way, even more surprising that Gonzales et al. still observed a beneficial effect on the libido of their 21–56 year-old male subjects.
- Garcinia cola - Commonly known as bitter kola due to its bitter taste,
the garcinia cola nut is traditionally served as refreshment. Medicinally, however, it has been used for centuries to treat abdominal pain, cough, laryngitis, liver disease infections and erectile problems (Irvine, 1961; Odebunmi et al., 2009). In previous studies, these effects have been ascribed to phytochemicals like biflavonoids, xanthones, triterpenes, cycloartenols and benzophenones (Terashima. 2002; Adaramoye. 2005 & 2006), agents of which scientists have found only recently that they can increase testosterone and male reproductive function, as well (Farombi. 2013). Sewani-Rusike et al. were inspired by the results Farombi et al. published in the Journal of Ethnopharmacol and investigated the effects of different doses of a crude extract of G. kola on
male sexual function after subchronic and chronic treatment periods at different sublethal doses (the lethal dose is 5000mg/kg in rats and 30g/kg in humans).
Figure 2: Testosterone, LH and FSH levels (left) as well as markers of sexual function, i.e. mount latency (ML), intromission latency (IL), the number of mounts and intro-missions (Sewani-Rusike. 2016).
Since the gross testicular histology was not affected by the 70% ethanolic extract of garcinia cola the scientists used in this study, the only thing that's missing to call garcinia cola a "proven T-booster" is the lack of human studies investigating its effects and safety at human equivalent doses of 16, 32, and 64 mg/kg body weight.
- Adaramoye, O. A., et al. "Comparative study on the antioxidant properties of flavonoids of Garcinia kola seeds." Pakistan Journal of Medical Sciences 21.3 (2005): 331.
- Adaramoye, O. A., and E. O. Adeyemi. "Hypoglycaemic and hypolipidaemic effects of fractions from kolaviron, a biflavonoid complex from Garcinia Kola in streptozotocin‐induced diabetes mellitus rats." Journal of pharmacy and pharmacology 58.1 (2006): 121-128.
- Farombi, Ebenezer O., et al. "Hepatic, testicular and spermatozoa antioxidant status in rats chronically treated with Garcinia kolaseed." Journal of ethnopharmacology 146.2 (2013): 536-542.
- Gonzales, G. F., et al. "Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men." andrologia 34.6 (2002): 367-372.
- Ohta, Y., et al. "Feeding hydroalcoholic extract powder of Lepidium meyenii (maca) increases serum testosterone concentration and enhances steroidogenic ability of Leydig cells in male rats." Andrologia (2015).
- Sewani‐Rusike, C. R., N. Ralebona, and B. N. Nkeh‐Chungag. "Dose‐and time‐dependent effects of Garcinia kola seed extract on sexual behaviour and reproductive parameters in male Wistar rats." Andrologia (2015).