Bulletproof Coffee – Why Is This Still a Trend?

Jennifer Lovejoy, Arivale Chief Science Officer, PhD
Jennifer Lovejoy
Arivale Chief Science Officer, PhD

Bulletproof Coffee – a blend of coffee, butter, and medium-chain triglyceride (MCT) oil – has been around for several years. This purportedly magical beverage is the brainchild of Silicon Valley entrepreneur Dave Asprey, who claims – based on his personal experience – that drinking Bulletproof Coffee (and only Bulletproof Coffee) for breakfast will cause weight loss, boost energy, and improve brain functioning.

Asprey’s managed to build quite a successful business on these claims, selling specialty coffee and supplements as well as a variety of Bulletproof diet products. In fact, his company, Bulletproof 360, announced in July it had raised an additional $40 million in funding, and Bulletproof Coffee opened a shop near Arivale’s Seattle headquarters late last year.

So, about those Bulletproof benefits…

Unfortunately, there’s no basis for any of Asprey’s claims. The flaws in the claims for Bulletproof Coffee were clearly elaborated shortly after the drink started gaining popularity (here, for example). And, an up-to-date review of the scientific literature doesn’t provide any reason to amend the arguments of those who’ve already debunked the Bulletproof Coffee myth.

There are a few things that are specifically worth calling out, however.

First, there have never been any clinical studies on Bulletproof Coffee per se, so its benefits as recommended are not based in any scientific evidence. There have been clinical studies on MCT oil that suggest its use may possibly cause small weight losses. In particular, a 2003 study1 is often cited. This was a study of 31 people comparing a 16-week weight-loss diet high in MCT versus one high in olive oil. At the end of the study, there was a difference of just over 3 pounds between the diet groups, which was statistically significant but likely not clinically significant. More recently, a 2015 meta-analysis of all the literature on MCT oil and weight loss2concluded that “further research was required” using better-designed studies since the current literature was not strong enough to draw any conclusions. This fact hasn’t changed in the last three years, and in Arivale’s clinical review of MCT oil as a supplement it gets a “two-star” confidence rating (out of possible five stars) due to lack of data on efficacy.

There is even less evidence for an effect of MCT oil on the brain. A couple studies have been done in individuals with Alzheimer’s disease that showed minimal effect3,4and one very small pilot study in six adults with Mild Cognitive Impairment5 that showed improved ketone bodies, which could relate to brain health. Notably, we didn’t find any studies that related MCT oil to cognitive function in healthy individuals or studies that looked at MCT oil as a preventative measure for age-related cognitive decline.

A key ingredient in Bulletproof coffee may be a problem.

There are also potential adverse effects of consuming MCT oil, especially at the high doses one might get in Bulletproof Coffee. In some people, MCT oil can cause significant increases in LDL-cholesterol and LDL particle number6,7. This is likely because of the high saturated fat content, especially in people who are genetically susceptible to adverse effects from saturated fat.

Not uncommonly, MCT oil also causes stomach upset and diarrhea.

Last but not least, several tablespoons of MCT oil as used in preparing Bulletproof Coffee provides over 200 calories – a significant amount if someone is working on weight loss. This is especially relevant since liquid meals are less filling than solid meals and may lead to further overeating at meals later in the day8,9.

Just because it tastes good doesn’t mean it’s good for you.

So, why is Bulletproof Coffee still a trend? It might be because there’s a lot of good marketing hype behind it driving a nice profit for Bulletproof 360. Or, perhaps it’s for the same reason deep-fried Twinkies continue to sell: Our brains have a bias toward the taste and texture of fat, so it may just be that Bulletproof Coffee tastes good.

But, as with many foods, don’t confuse tasting good with being good for you. Apart from the lack of evidence of benefits and possible negative effects described above, consider what you could be having for breakfast instead of Bulletproof Coffee: a satisfying and nutrient-rich meal based on whole foods that will fuel your body and brain until lunch. (We just happen to have a few suggestions.) That’s a more sane and sustainable way to get your day off to an optimal start!

Further reading:



  1. St-Onge MP, Jones PJH. “Greater rise in fat oxidation with medium-chain triglyceride consumption relative to long-chain triglyceride is associated with lower initial body weight and greater loss of subcutaneous adipose tissue.” Int J Obesity 27.12 (2003): 1565-1571.
  2. Mumme K, Stonehouse W. “Effects of medium-chain triglycerides on weight loss and body composition: a meta-analysis of randomized controlled trials.” J Acad Nutrition and Dietetics 115.2 (2015): 249-263.
  3. Sharma A, Bemis M, Desilets AR. “Role of medium chain triglycerides (Axona®) in the treatment of mild to moderate Alzheimer’s disease.” Amer J Alzheimer’s Dis Other Dementias 29.5 (2014): 409-414.
  4. Ohnuma T, et al. “Benefits of use, and tolerance of, medium-chain triglyceride medical food in the management of Japanese patients with Alzheimer’s disease: a prospective, open-label pilot study.” Clin Interventions Aging 11 (2016): 29.
  5. Rebello CJ, Keller JN, Liu AG, Johnson WD, Greenway FL. “Pilot feasibility and safety study examining the effect of medium chain triglyceride supplementation in subjects with mild cognitive impairment: A randomized controlled trial.”  BBA Clin. 2015 Jan 16;3:123-5.
  6. Cater NB, Heller HJ, Denke MA. (1997). “Comparison of the effects of medium-chain triacylglycerols, palm oil, and high oleic acid sunflower oil on plasma triacylglycerol fatty acids and lipid and lipoprotein concentrations in humans.” Am J Clin Nutr. 1997 Jan;65(1):41-5.
  7. “Bulletproof Coffee May Hike Lipids.” MedPage Today/American Association of Clinical Endocrinologists. May 16, 2014. https://www.medpagetoday.com/meetingcoverage/aace/45810
  8. Tieken SM, Leidy HJ, Stull AJ, Mattes RD, et al. “Effects of solid versus liquid meal-replacement products of similar energy content on hunger, satiety, and appetite-regulating hormones in older adults.” Horm Metab Res. 2007 May;39(5):389-94.
  9. Martens MJ, Lemmens SG, Born JM, Westerterp-Plantenga MS. “A solid high-protein meal evokes stronger hunger suppression than a liquefied high-protein meal.” Obesity 2011 Mar;19(3):522-7.