At 53 years of age, Joe Rogan is in better physical shape than many 30 year olds. And it’s not just his physique that’s impressive, he’s also managing to stay mentally sharp too.
Whether he’s injecting testosterone, devouring elk meat or hulking down vegetable smoothies, Joe is always on the look out for performance enhancing substances.
In this post we’ll look at both the products Joe takes regularly, and products he takes occasionally or is experimenting with.
Joe Rogan’s Daily Vitamin & Minerals:
- Multivitamin – Pure Encapsulations Athlete Pure Pack
- Omega-3 Fish Oil – Carlson Omega-3 Fish Oil
- Vitamin D – Thorne Research – D3 5,000iu
- Quercetin – added recently
- Glucosamine and Chondroitin – 365’s Glucosamine Chondroitin & MSM
Products Joe takes frequently, occasionally or is experimenting with:
- Resveratrol & NMN (Nicotinamide Mononucleotide) – see below
- Nootropics – Neuro1, TruBrain, AlphaBrain & Neuro Gum
- Pre-workout – Shroom Tech Sport
- Hemp/CBD Oil – Charlotte’s Web
- Kratom – see below
- Nut Butters – see below
- Coffee – see below
Hormone Replacement Therapy
- Testosterone Replacement Therapy (TRT)
Table of Contents
- 1 Joe’s Daily Vitamins & Minerals
- 2 Products Joe Takes Occasionally/Is Experimenting With
- 3 Testosterone Replacement Therapy (TRT)
- 4 Closing Words
- 5 Change Log
Joe’s Daily Vitamins & Minerals
Multivitamin – Pure Encapsulations Athletic Pure Pack
You can see from this old video clip that Joe has always taken a lot of supplements. However, as far as we can tell from his podcasts, he keeps things a bit simpler these days.
Joe says he uses a multivitamin called Athletic Pure Pack – which comes in “on the go” sachets.
Each sachet contains a number of pills, specifically:
- Vitamins & Minerals – 3x capsules
- EPA/DHA Omega-3s – 1x capsule
- Creatine (Kre-Alkalyn) – 2x capsules
- Vitamin C (Ascorbic Acid) – 1x capsule
- Coenzyme Q10 – 1x capsule
- L-Glutamine – 1x capsule
The clip below has Joe mentioning Athletic Pure Pack – from his #802 podcast with Tom Papa (full video on Spotify). They start talking about supplements from 1hr 8mins, and the specific mention of Athletic Pure Pack is at 1:14:37.
For those who want a multivitamin, but don’t necessarily need the extras, Pure Encapsulations also make a multi called O.N.E. It is used by Joe’s regular guest Dr Rhonda Patrick. For more discussion on O.N.E see this post on Dr Rhonda Patrick’s supplements.
Omega-3 Fish Oil – Carlson’s Super Omega-3
Joe places a high value on omega-3 fish oils, and ensures he’s taking them regularly. In the same Tom Papa podcast above, you can skip to 1:02:40 where they talk about the importance of fish oils, and how it’s more effective than getting your omega-3s from flax-seed or hemp oil.
Based on Joe’s Instagram post, the old video tour of his vitamin cupboard, and a recent Dr Rhonda Patrick podcast, Joe currently takes Carlson’s Super Omega-3 fish oil in liquid form. He currently takes 3 tablespoons daily (he specifically mentions this dosage in a recent podcast with Rhonda Patrick).
If you find capsules more convenient (as I do), Carlson also do an encapsulated version; Elite Omega-3 Gems. A 2 capsule serving contains 1,600mg omega-3s, including 800mg EPA & 600mg DHA.
Vitamin D3 – Thorne D-5,000
Joe recently had Dr Rhonda Patrick on the show (#1474), and they did a deep dive into research around vitamin D and its benefits. Particularly in regard to reducing the risk of respiratory tract infections. Rhonda pointed to a possible link between low vitamin D levels, and increased severity of Covid-19 disease.
Both Rhonda and Joe shared that they’re taking 5,000iu of D3 daily. Specifically, Rhonda aims to maintain a blood concentration of 40 – 60ng/ml, using occasional blood tests to calibrate the correct amount of D3 she needs. She points out that not only is too little D3 bad for us, too much is also not good. See her video on Vitamin D3 for more details.
Rhonda currently takes her vitamin D3 in the form of Thorne’s D-5,000, and I’d imagine Joe takes the same or similar now.
Dr Gordon suggested Quercetin can:
- Reduce inflammatory cytokines (which you don’t want elevated unnecessarily)
- Increase mitochondria (which helps with energy production)
Dr Gordon would get patients to take 500mg 2x per day, along with Zinc 15mg 2x per day. They found this dropped the number of colds people were getting, and their allergies were improving. He didn’t fully understand why this was happening, until this year with Covid, where he learnt how much of an effect zinc can have on the immune system.
He explains that in the context of viruses and Covid, zinc can inhibit the viral replication within cells. Quercetin’s role in the process is to get the zinc across the cell membrane and into the cell. Without an ionophore like Quercetin, Zinc has a harder time getting into cells.
In terms of supplement doses, Marks says when treating someone who has Covid, they would increase the dose of Quercetin to 1,000mg 2x per day, and Zinc to 30mg 2x per day.
Glucosamine & Chondroitin – 365
Since Joe was young, he trained as a Taekwondo fighter, competing nationally. Even after he finished fighting competitively, he still trains hard. This leads to a lot of wear and tear on the joints, and thus Joe uses glucosamine & chondroitin.
He first mentioned it in a 2009 post on MMA underground:
Products Joe Takes Occasionally/Is Experimenting With
Resveratrol & NMN (Nicotinamide Mononucleotide)
- Resveratrol – 1g/daily (morning with yogurt)
- Nicotinamide Mononucleotide (NMN) – 1g/daily (in capsules, swallowed with water)
During the podcast Joe creates a list of these supplements to go shopping for later. Then on episode #1269 Joe confirms he has started taking resveratrol every morning, along with NMN which he says gives him a lot of energy and makes him feel great.
What do Resveratrol & NMN do in relation to living longer?
David describes resveratrol and NMN as critical for the function of the sirtuin genes, genes which help us live longer. He describes resveratrol as the “accelerator pedal” for the sirtuin genes (increasing their activation), and NMN as the fuel. The reason that resveratrol won’t work effectively without NMN (the “fuel”), is that sirtuin activation requires youthful NAD levels, but NAD levels decline with age, and by 50 years old, we have about half the level of NAD we had in our 20s (NAD being a molecule that is essential to energy production in our cells).
So in effect, you take resveratrol to increase activation of the sirtuin genes, and NMN to ensure the sirtuins have enough energy to work properly. It’s worth noting that restoring NAD levels has other helpful benefits too.
The complexity with these 2 supplements is that David Sinclair (who recommended them), uses product he had leftover from lab experiments – and Joe hasn’t shared explicitly which brand he uses (and no doubt brand matters, given that supplement manufacturers are unregulated). I dug into the subject in detail in the David Sinclair post, so refer to that for more details, but below is shorter version.
Research published by David’s old company Sirtris (sold to GSK for $720m) found that micronized resveratrol had greater bioavailability than its regular, non-micronized counterpart, specifically up to 3.6x greater when measured in the blood. Searching micronized resveratrol on Amazon narrows down the results down to a few; including MegaResveratrol.
However, I noticed something on the page for the Rich Roll interview with David Sinclair. He lists a micronized resveratrol by RevGenetics. This was interesting because during the interview Rich asks David where to get the supplements he takes, and David told him they’d talk about it after the podcast. Maybe RevGenetics was a brand that David mentioned post interview (possible), or perhaps it was just a brand Rich “plucked” from a Google search. Impossible to know without further info.
That said, I looked into RevGenetics a little more, and they certainly seem legitimate. They focus on longevity molecules and have been selling Resveratrol since 2006. They offer a micronized resveratrol that comes in powder form, and thus could be taken in the morning with yogurt, as David does. It’s named M98 Super Micronized Resveratrol.
If like me, you’re curious about the daily cost… at 1g/day it works out at $3/day ($75 per 25g tub). If you buy 2 or 3 tubs you get a discount, and it comes down to $67.50 per tub, so $2.70/day.
NMN (Nicotinamide Mononucleotide)
In the interview David refers to two molecules that can act as “gas” for the sirtuin activator (resveratrol) to work; NMN and NR (nicotinamide riboside). It’s not clear yet how NR compares to NMN in terms of effectiveness – those studies are still to be done. However, David speculates based on the animal studies done so far that NMN may turn out to be the superior molecule in terms of raising NAD levels in cells.
However when it comes to NMN, there isn’t a clear brand leader.
Searching online there are a large number of possible options. Without doing ones own 3rd party lab testing, it’s hard to evaluate the quality of products. What I’ve done below is put some of the more highly reviewed options into a table, calculated the approximate price per gram, and added links to any 3rd party analysis certificates the companies display.
|Product||Approx. price per gram||3rd Party Analysis Certificate?|
|Double Wood (30g powder)||$3.83/gram ($115 / 30g) - using $15 off coupon code||Yes (link) - via Colmaric Analyticals|
|ProHealth (15g powder)||$4.60/gram ($69 / 15g)||Yes (link) - via Micro Quality Labs|
|Genex (15g powder)||$4.60/gram ($69 / 15g)||Yes (link) - via Micro Quality Labs|
|RevGenetics Advanced NMN (25g powder)||$15.8/gram ($395 / 25g)||Yes (link) - via Intertek|
|Double Wood (125mg capsules)||$5.86/gram ($44 / 7.5g) - using $5 off coupon code||Yes (link) - via Colmaric Analyticals|
|ProHealth (150mg capsules)||$5.44/gram ($49 / 9g)||Yes (link) - via Micro Quality Labs|
|Genex (125mg capsules)||$6.66 ($50 / 7.5g)||Yes (link) - via Micro Quality Labs|
For further information on the topic of Resveratrol and NMN, see this longer post I did on David Sinclair’s Supplements – What He Takes & Where to Buy – including additional information we’ve learnt since David was on JRE.
In a January 2019 podcast episode (JRE #1234 ), Joe discussed the 3 nootopic supplements he likes & takes; Neuro1, TruBrain & AlphaBrain.
“There’s a bunch of different nootropics I use. I use 3 different companies, 1 that’s one of mine (AlphaBrain), and then 2 that are other companies; Neuro1 and another one called TruBrain”
Joe has mentioned Neuro1 numerous times over the years (for example see Joe’s below tweet from 2013). It’s a nootropic created by former NFL linebacker Bill Romanowski, who after 16 years, and many hits in the NFL, was suffering from memory problems. In 2007 he brought together doctors, scientists and nutritionists to create a solution to fix his cognitive decline. This resulted in the product Neuro1.
Note: Whilst Neuro1 lists ingredients, it doesn’t list quantities (not good). Their website says “one serving of Neuro1 is equivalent to about 1 cup of strong coffee”, so around 100mg to 120mg of caffeine per serving.
Joe interviewed the neuroscientist behind TruBrain, Dr Andrew Hill, on JRE #629. Similar to Neuro1 above, it shares active ingredients caffeine and piracetam, but then adds oxiracetam to the stack. They come in these “on the go” pouches, that work out to be a couple of dollars per dose.
AlphaBrain is made by Onnit, a company that Joe has openly said he owns a stake in. He also notes that all the supplement’s ingredients could be bought separately for less, it would just require more time and effort. There are two versions; pill form (Alpha brain) and sachet form (AlphaBrain Instant). In case it’s of use, for 10% off AlphaBrain (and anything else at onnit.com) you can use this coupon code.
Unlike Neuro1 and TrueBrain, AlphaBrain doesn’t include caffeine. It’s active ingredients include:
- Alpha GPC
- Huperzine A
Alpha GPC, a type of choline, is also favoured by Dr Rhonda Patrick, a regular guest on Joe’s podcast. She takes around 800mg (substantially more than 2 capsules of Alpha Brain contains) before intense writing or public speaking events. See more on Rhonda’s use of it here.
Interestingly, Onnit did sponsor a 63 person study (source) showing that Alpha Brain improved “delayed memory recall” vs a placebo. Specifically that’s where participants are told/shown something, then a break occurs, then they’re later asked questions that requires them to recall the information they were earlier provided. Now, given that Onnit sponsored the study, we should use appropriate scepticism in interpreting their positive results; but thought it interesting to mention nonetheless.
Joe talked about his Onnit “essentials” including Alpha Brain and Shroom Tech Sport on Instagram – August 2019.
Each piece contains caffeine (40mg), L-Theanine (60mg), B6 and B12 vitamins. L-Theanine is found naturally in tea, and many find it “smooths out” the stimulant feeling from caffeine.
It’s available in two flavors; mint (blue packaging) and cinnamon (orange packaging). Worth noting that they make 2 different products; mints and gum.
Shroom Tech Sport
Joe takes Shroom Tech Sport as a pre-workout, about an hour before exercising. He says it allows him to push harder in the gym, without giving him the jittery feeling that strong caffeine based pre-workout supplements do.
It contains a number of interesting ingredients:
- Vitamin B12 – important for energy production, but the effects are typically only noticeable if you’re low in B12
- Chromium – thought to play a role in insulin regulation1 – which in turn is important for the bodies energy management
- Cordyceps mushroom – supposed to improve athletic performance – data currently inconclusive
- Ashwagandha – an “adaptogen” that appears particularly adept in helping manage stress/anxiety2
- Green tea extract – this likely means the supplement contains small amounts of caffeine and l-theanine, which come from tea leaves
- Rhodiola – popular “adaptogen” – supposed to boost energy
- Astragalus – has been researched as a drug to improve healthspan – unclear how it helps with sports performance
Onnit also published a clinical trial that found Shroom Tech Sport increased volume for strength training and high-intensity cardio. The full study is here, and their blog post about it here. Naturally, given it was self-funded, it should be approached with healthy skepticism.
In case it’s of use, for 10% off Shroom Tech Sport (and anything else at onnit.com) you can use this coupon code.
Joe explains he uses hemp oil in 2 different forms:
- As an oil taken orally – he says it “puts me in a great place”. Specifically mentioning how it has “saved family vacations” by reducing his anxiety.
- As a cream used topically – Joe exercises a lot, and says “it’s probably the best thing I’ve found for alleviating soreness and stiffness”
It's worth taking a moment just to clarify around the legal difference between hemp oil and CBD oil. The hemp plant is defined in US Federal law via the 2018 Farm Bill as a cannabis plant with less than 0.3% THC content on a dry weight basis (see Farm Bill section 10113 specifically). Oil extracted from the hemp plant is referred to as "hemp oil" - and can be sold legally across the USA - including on Amazon.com.
A large amount of the time when people say "CBD oil" they are referring to what's legally regarded as "hemp oil". The CBD part of the name refers to cannabidiol, one of the 113 cannabinoids in the cannabis plant. However, in states where cannabis is available for medicinal or recreational purposes, it is possible to get oil made from cannabis plants over the 0.3% THC threshold - at which point this would no longer be referred to as hemp oil, and would be considered a scheduled substance. The rest of this post only refers to the federally legal hemp oil.
Whilst Joe has experimented with different brands of hemp oil, the brand Charlotte’s Web has specifically been talked about a few times on the podcast, after Joe was first introduced to it by Pete Holmes in 2017 (see clip from JRE #912).
Whilst CBD containing hemp oil has become big business, and lots of new sellers have flooded the market, Charlotte’s Web has been there since the early days, and appear to pride themselves on quality. Each product bought from them can be checked on their website for a certificate of analysis, detailing the levels of cannabinoids as well as heavy metals, pesticides, solvents, and THC found in the batch.
I’ve reached out to Charlotte’s Web, and they’ve kindly provided a 15% discount code for readers of this blog. To redeem it, use the coupon code FLH on the Cart page. It works for all products except “bulk” and “bundles”.
Joe is also a fan of Kill Cliff CBD infused drinks. Each can contains:
- 25mg of CBD, with 0% THC
- 0% sugar – using mostly erythritol and to a lesser extent, stevia as sweeteners
- 25mg caffeine – 5mg from green tea extract, 20mg added (source)
- Taurine, ginseng, green tea extract, ginger root
- B vitamins (B2, B3, B5, B12)
- Potassium (electrolyte)
Joe’s posted about them multiple times on Instagram (here, here and here), for example saying “I found my new favourite beverage”, and “it’s amazing how much good you can get out of a 24 kilogram kettlebell and a can of mango @killcliff”. Granted he’s on their ambassadors page – so he may not be unbiased.
Price-wise, they don’t work out cheap. Their 12-pack single flavors (such as mango, orange, grape or strawberry) are approximately $6.16 per can, and their 12-pack of mixed flavors are $6.58 per can (including $5 shipping).
Then in 2018, episode #1136 he shares with Hamilton Morris that he’s on Kratom while they speak – to help curb the pain of a recent knee injury (see clip). Then later on #1296 he discusses the effect of different doses, with smaller doses being a stimulant, and higher doses being a relaxant (see clip).
Kratom is the powdered leaves of a plant from SE Asia called Mitragyna speciosa (you can see why the simpler name “kratom” caught on). It has 2 main properties:
- At lower doses, it acts as a mild stimulant
- At higher doses, it acts as a pain-killer
It’s most commonly used for 2 issues:
- Beating opioid addiction – whether that’s from “street drugs” like heroin, or from prescription drugs like OxyContin.
- Chronic pain management – as an alternative to prescription drugs.
Other, less common, uses include:
- Social anxiety – helping users to feel more confident and relaxed in social situations
- Bodybuilding – to help train longer and harder in the gym
Similar to the way all types of tea we drink (black, green, white etc) are derived from the same species of plant; camellia sinensis, all types of kratom are derived from a single species of plant also – called mitragyna speciosa.
Often kratom gets segmented into 3 colors: red, green and white. The colors refer to the veins within the leaves. However, during processing the veins and stems are cut out, so that what you receive all looks similar; a green ground-up powder.
Then within each color the products are often further segmented, in order indicate subtle differences between the plants. For example, popular red kratoms are Bali, Borneo and Maenga Da. For more information on kratom strains, see this post on reddit.
Is Kratom Addictive?
Even though kratom is a “natural” product, it can still be addictive, particularly if taken daily. For people who are dealing with chronic pain, then this is less of an issue, given they may need to take addictive pain killers daily anyway. However, when used recreationally, addiction is something to watch out for. There’s a good video on the Psyched Substance YouTube channel here, about the risks of kratom addiction. There is also a thread on Reddit around how to quit (suggesting it’s not easy once addicted).
Is Kratom Legal?
Kratom’s legal status varies from country to country, and you should be aware of the status where you are. In the USA kratom is federally legal, but some individual states and cities have made it illegal. For example it’s legal within California except for in the city of San Diego. There has been discussion (link) to make kratom federally illegal, but this has not happened so far.
Where to Buy?
Assuming kratom is legal in your location (see above) then kratom can be purchased both in head shops and via online stores. I’ve listed a couple of options below:
|Type||Price per Gram||Total Price||Seller|
|White Maeng Da (60 Capsules)||$0.50/gram (or down to $0.30/gram with larger quantities)||$16.00||Super Speciosa|
|Red Bali Kratom (60 capsules)||$0.50/gram (or down to $0.30/gram with larger quantities)||$16.00||Super Speciosa|
Joe’s company Onnit produce a range of nut butters they call “fat butter” – due to their high fat content. These are particularly interesting for people on low carbohydrate diets, who want to add more tasty fats to their diet. They come in 4 varieties:
- Salted Almond – almonds, macademia nuts, chia seeds, coconut oil, pink himalayan salt
- Creamy Peanut Butter – peanuts, macademia nuts, chia seeds, coconut oil, pink himalayan salt
- Chocolate Hazelnut – Hazelnut, cashew, cocoa butter, cocoa powder + more
- Snickerdoodle – Cashew, macademia nuts, cocoa butter, hemp seed + more
In case it’s of use, for 10% off the nut butters (and anything else at onnit.com) you can use this coupon code.
Ok, so, coffee – what’s the big deal? It’s one of the most common drinks in the Western world, and probably not worthy of a special spot in this list. True.
But at the same time, coffee is one of the strongest (unregulated) cognitive enhancers available to man – and Joe’s a big fan.
Whilst it may be difficult to find reliable evidence on the effectiveness of some of Alpha Brain’s ingredients, there are hundreds of studies on caffeine and its effects.
UFC star Chael Sonnen has talked in the past about how he’s able to supplement caffeine before a fight, and it gives him a boost.
Coffee Joe has mentioned drinking:
- Caveman Coffee Nitro Cold Brew – A single estate coffee, “infused’ with nitrogen, containing 250mg caffeine per can (source IG)
- Black Rifle Coffee – a coffee range by Joe’s bow hunting friend John Dudley (source IG)
- Four Sigmatic Mushroom Coffee – a sponsor of the podcast, but also something Joe likes, particularly their Lion’s Mane & Chaga mix
Joe has also recently got into using a coffee creamer by his friend’s business – the surfer Laird Hamilton. It’s a coconut based creamer (dairy-free, vegan and keto friendly) that contains turmeric. He mentions enjoying it on the Dan Crenshaw podcast, and also displays it on an Instagram post.
- Laird Superfood Coffee Creamer – Turmeric version
Testosterone Replacement Therapy (TRT)
Whilst some people start slowing down in their 50s, Joe hasn’t. Whether he’s hosting his podcast, practicing stand-up comedy or commentating at UFC events, the man doesn’t stop.
Part of this can be put down to “success”, a healthy lifestyle and good genetics. But it would be a mistake to ignore the elephant in the room; Testosterone Replacement Therapy (TRT).
Joe says he started testosterone replacement therapy at age 37/38, originally using creams, which weren’t very effective. Then at 39 (now 51) progressing to weekly injections, under the close supervision of his doctor. Raising his testosterone to the levels he would have had in his late 20s. Joe on TRT:
“Testosterone replacement therapy, there’s a real science to it.
The idea is you don’t take too much, you take what you would have in your body if you were a younger man.
People are like well you’re not a younger many anymore well, duh, like, people just want you to wither away and die.”
In the next clip, Joe goes on to say:
“All that matters is that you have testosterone in your system. If you don’t have it in your system, you’re not going to feel as good.
It’s real simple, if you’re fine, with not feeling as good – good! If you’re not fine with it, this is 2018, hormone replacement exists for a reason – and that reason is that it makes you feel way better, it makes your body work way better.
You can avoid a host of ailments and conditions related to your body breaking down due to age with hormone replacement therapy. The key to doing it though is to do it correctly. You’re supposed to go to a doctor who is going to test your blood levels, test your nutrient levels, and adjust your diet first.
The first thing that happens, they want to find out:
- How much you’re sleeping
- How stressed out you are
- How much water you’re drinking
- Are you getting the proper amount of protein – are you eating correctly?
Then they want to get you off the:
Before you do anything.
This is a many month process that I went through. They get you off of all these different things first.
Then they start adding testosterone. It takes a bit of time to figure out what works best. And then you get to a point where you have the hormone levels of a healthy young man. You don’t want to elevate, you don’t want to be higher than that. That’s where you get problems.
There’s ways of elevating your hormones naturally, they just don’t work as well. Whether it’s deadlifts, or running hills, doing sprints, they work a little bit better than nothing. But there’s going to be a difference.”
So as you can see – Joe’s a big fan of hormone replacement therapy. It seems to be fairly undisputed in the medical community that testosterone decreases with age. One study3 suggests “free testosterone”4 (the metabolically active testosterone not bound up with SHBG or albumin) decreases by 2% per year from the age of 40. The study notes that poor health may accelerate the age-related decline in hormone levels. So the healthier we can keep our bodies, the slower the decline may be.
Traditionally, testosterone replacement therapy has been thought of as something only a small percentage of the population need, if they have chronically low levels of testosterone. Rather than seeing the age-related decline as something to be fixed. Now, gradually, it’s become more mainstream, as a method for those who can afford it to improve their quality of life as they age.
It’s not something to be taken lightly however, and you certainly don’t want to take testosterone if you don’t need it. As Joe has done, the therapy needs to be taken under the guidance and supervision of a doctor who specializes in hormone replacement therapy – with regular blood tests and check ups. They will be best positioned to discuss the complexities of the treatment, and whether or not it’s something that would be safe and beneficial to take.
Hopefully this post has given you a window into the products Joe takes to keep himself healthy and in shape.
Let me know in the comments if you’ve any questions.
I’ve added a post change log here, starting May 17, 2020.
See Post Sources Below:
- A scientific review: the role of chromium in insulin resistance – PubMed 2004
- A Prospective, Randomized Double-Blind, Placebo-Controlled Study of Safety and Efficacy of a High-Concentration Full-Spectrum Extract of Ashwagandha Root in Reducing Stress and Anxiety in Adults – K. Chandrasekhar et al – 2012
- Age Trends in the Level of Serum Testosterone and Other Hormones in Middle-Aged Men: Longitudinal Results from the Massachusetts Male Aging Study – Feldman et al (2002)
- Free testosterone: clinical utility and important analytical aspects of measurement – Shea et al. (2014)