Question: "What do you think of alternative testing like hair mineral analysis or SpectraCell?"   I'm against SpectraCell on the basis of, it's not validated. I gave more details in a podcast episode "What Makes a Good Marker of Nutritional Status?" and you can find that at chrismasterjohnphd.com/marker.   Hair mineral analysis; I like hair mineral analysis when there is nothing better and more validated. For a lot of the trace minerals where we don't have good, validated markers of nutritional status, so I think hair mineral analysis is good. I also think hair mineral analysis is good if you don't have the money to do something comprehensive with all the best markers, and you want something that can clue you in when something might be off. So, the nice thing about it is, with less money, you cover all the minerals. The less nice thing about it is, it's not very well validated quantitatively.    Even where there's data, like for example — it is validated that your iron in your hair tends to be higher when your iron in your body is higher, and vice versa. But it's not validated to say, when hair is X amount, this is when you need more iron, and when hair is Y amount, this is when you need less. The way that the blood markers are — like transferrin saturation, ferritin, hemoglobin, all these more validated markers. We have tons of quantitative data saying — the normal range is this — the optimal range is this.   You lose the precision when you go back to the hair mineral analysis. I wouldn't use it — the thing is, if you spend $200 on a hair mineral analysis, that's $200 that you can't put towards your Genova ION Panel, or you could have gotten four iron panels with that, right?  So, you have to be careful that if your financial resources are constrained, you might want to do the hair mineral analysis on that basis, but it might be a better financial decision long-term to hold onto that money and do free stuff.   In Testing Nutrition Status: The Ultimate Cheat Sheet, what I say is, if you don't have the money for the comprehensive testing, you focus on the things that are free.    You do the dietary and lifestyle analysis.    You do the symptom analysis.    Then you go to the things that that indicates is most probable, and then you do the best validated test. Maybe this diet and symptom analysis all points you to iron, and you spend $60 on the iron panel, and that gives you more payoff than $200 on a hair mineral analysis.    So, it's not an obvious choice about when to get the suboptimal test. It's something you have to think about carefully.   This Q&A can also be found as part of a much longer episode, here:https://chrismasterjohnphd.com/podcast/2019/02/09/ask-anything-nutrition-feb-1-2019/    If you would like to be part of the next live Ask Me Anything About Nutrition, sign up for the CMJ Masterpass, which includes access to these live Zoom sessions, premium features on all my content, and hundreds of dollars of exclusive discounts. You can sign up with a 10% lifetime discount here: https://chrismasterjohnphd.com/q&a