Just started taking Alcar in the morning, when having previously only ever done it in the afternoon/early evening!!

Sometimes it is. Sometimes it is about pulling those fat-soluble compounds out of the insoluble plant materials they are in. Sometimes it is about bile salt excretion. Sometimes it is about slowing down gastric motility. Sometimes it is about adjusting stomach pH. Sometimes it is about enveloping and protecting compounds till they reach the small intestine. Sometimes it is about reducing the osmotic effect in the lining of the stomach/intestine. What it is NOT is a universal rule that if something is fat soluble it needs to be taken with fat to absorb properly. That's wrong, and a lazy way to explain away the intricacies of oral bioavailability. Even people's understanding of water/lipid solubility is wrong. Things can be both water and fat soluble. Look at pramiracetam. That has water-soluble and fat-soluble functional groups. Even how we measure solubility varies. It is much much more complex than people ever discuss.

Most people refer to the partition coefficient (logP), which is the logarithm of 1-octanol/water partition coefficient, when discussing a compound's hydrophobicity/lipophilicity. The two most common methods for measuring that are AlogP and ClogP, but there are more. AlogP, or atomic logP, assumes that each atom in a compound has a contribution to the solubility, and that the final value is additive in nature. It is a good simple system for small molecule organics, but not good for things with complex aromaticity or electrical situations that have unpredictable contributions to a compound's logP. There is also enhanced atomic logP, or XlogP, that attempts to address these shortcomings. However, that is not as common. That uses the values of each atom type, as well as a contribution from its neighboring atoms, along with correction factors to give a better picture of lipophilicity. Both are additive in nature, and are looking at individual atoms in a compound to get an idea of its solubility.

ClogP, or compound/fragment logP, is a method that uses a dataset from whole compounds/fragments which are experimentally determined. Then they are modeled using QSPR or other regression techniques in small fragments, rather than simple calculations per atom. Those contributions from fragments are then added up, with correction factors being applied, to get a value. The thought here is that sometimes a simple calculation of each atom's addition to a compound's lipophilicity doesn't adequately capture the nuances of electronic or intramolecular interactions, and that fragments are better suited to model a compound's solubility. ClogP is better for larger molecules, or ones with complex aromaticity. There are a bunch of other methodologies for measuring a compound's solubility as well, but I won't get into those. One that you might look up is Moriguchi’s method, or MlogP. That was developed by Ikuo Moriguchi fairly recently. Also, logP is only one part of the greater "Lipinki’s Rule of 5” system for determining something's bioavailability.

So you can see even just calculating a compound's solubility is not a simple thing like everyone assumes. Solubility is not just A/B. It's not a simple: "This one is fat soluble, this one is water soluble..." If even knowing the solubility of a compound is that complex, imagine adding in the complexities of a biological system into the equation. It becomes something probably 100 times more complex than most people assume. Even just thinking about where certain things absorb in the GI tract is something most people don't look at. Ethanol absorbs in the stomach. Calcium, magnesium, iron, copper, vitamin A, etc. all absorb in the duodenum. Zinc, chromium, vitamin C, amino acids, small peptides, etc. absorb in the jejunum. Bile salts and vitamin B12 absorb in the ilium. Sodium, chloride, potassium, vitamin K, biotin, and short-chain fatty acids absorb in the large intestine. We are extremely complex systems, and chemistry is extremely complex on its own. I first went down this path when I started trying to experimentally verify all the solubility claims I was seeing online. Everyone was so sure in their statements for not only various compound's solubility, but how best to take them. When I started trying to verify these things in the lab, pretty much everything I read was wrong. A majority of the claims I saw online could not be replicated in a lab environment. So I started to ask why. Is it just everyone is parroting around false claims they hear? Sure, that is part of it. However, the more I dug the more I realized it is not a simple thing to answer. People were parroting around false information, but getting the correct information was not as simple as I assumed. Getting to the "right" answer was difficult, and the answers changed depending on how you attempted to measure them. To be honest, the more you look into anything you were taught or heard over the years, the more you realize that everything is bullshit, and nobody really knows what they are talking about. At least once you reach that point, you can put things into perspective. However, you are still left with that disbelief. "All these doctors can't be completely wrong, right? I have to be missing something. Everyone can't be in completely over their heads, can they? All the people you thought knew what they were talking about can't just be parroting around false and misleading things!" Eventually that disbelief fades, and you are just left with the cynicism. LOL

So no, you do NOT always need to take fat with fat soluble compounds for them to absorb. Those words don't even begin to describe the situation to begin with.