I just wanted to drop this out there for you folks. The reason I don’t take L-serine is that it promotes cancer. Glycine does the same thing without promoting cancer.
Serine, but Not Glycine, Supports One-Carbon Metabolism and Proliferation of Cancer Cells
https://www.cell.com/cell-reports/pdf/S2211-1247(14)00347-7.pdf
Please consider this information if you decide to continue taking L-serine.
Glycine also tastes way better than serine so much so that it can basically replace sugar for those with a sweet tooth. Same can’t be said for serine.
About L-serine (I don’t have an opinion on the matter, just FYI…):
That’s potentially bad news for me. I started taking it before bedtime recently for sleep and to my surprise my stress management scores really improved.
Did glycine have similar results?
I was already taking glycine at 1-3g before sleep which has been helpful.
Edit: I didn’t notice the stress management score change with glycine but perhaps I need to try a higher dose.
Due to the potential health hazard (cancer) I would stop taking L-serine and maybe up your glycine dosage. I think you will achieve the same results regarding sleep without potentially ruining your health.
There is absolutely no indication that l-serine causes any cancers any more than sugar causes cancer. Cancer cells use glucose as their primary fuel. Cancer cells also depend on arginine and glutamine. L-serene is not the primary fuel for cancer growth.
Interestingly: “Some cancer cells can’t use ketones as energy. Early studies show that changing your diet to be high in fat and low in carbohydrates can starve cancer cells.”
Here is a quick guide to diets and supplements that might help treat cancer.
Alternative cancer diets | Coping with cancer | Cancer Research UK.
Ketogenic diet in cancer management: Ingenta Connect
What do people take Serine for?
“What do people take Serine for?”
A sleep aid.
OUCH, just started taking it and I liked the effects. Will have to shelf it for now. Cancer is a scary bastard!
There is absolutely no correlation between getting cancer and l-serine supplementation. L-serine is less dangerous than your sugar consumption if you get cancer. Cancer depends on sugar, arginine, and glutamine. L-serene is not the primary fuel for cancer growth.
If you read the paper I posted at the beginning of this thread, you will find that the research showed that cancer cells use serine to grow, prosper and spread. Glycine was shown to inhibit cancer growth.
If you are going to choose an amino acid that is going to help in sleep, and serine and Glycine are equally effective, why on earth would you pick the one that cancer likes and not the one that inhibits it?
Another good paper on serine and cancer. For me, this is the key point for Rapa users:
Furthermore, the pathways of serine uptake and synthesis are usually upregulated in cancer, which reflects the dependence of tumor growth on serine. Similar to tumor cells, proliferating immune cells in vitro and in vivo are highly dependent on serine [4]. Some key regulators that mediate serine synthesis and metabolism also affect the growth, proliferation, and differentiation of immune cells [5-7]. Thus, both tumor cells and immune cells require an abundant supply of serine, suggesting that immune cells must compete with tumor cells for limited serine resources during the antitumor immune response.
What this tells me is that when cancer is present, cancer and your immune cells compete for serine. If the immune cells grab the serine, they prosper and wipe out the cancer.
With Rapa, we are suppressing the immune cells leaving most of the serine for cancer cells.
Remember that we have cancer in our bodies all the time. It’s just that our body’s immune system usually takes care of it. Taking Serine and Rapamycin appears to be a dangerous combination IMHO.
As I pointed out, serine is a more effective sleep aid for many people even though they both use the same pathway.
No, it is only bad after the fact. Cancer isn’t the only process that uses the 1C donors.
“One carbon (1C) metabolism is critical for early development as it provides 1C units for both biosynthesis of DNA, proteins, and lipids and epigenetic modification of the genome. Epigenetic marks established early in life can be maintained and exert lasting impacts on gene expression and functions later in life”
One Carbon Metabolism and Early Development: A Diet-Dependent Destiny - PMC.
Yes, it can be good for early-stage development of children. I think most of us here are past that stage… at least physically. 
In the end, each person makes the best decision based on their own knowledge and preferences. For me, cancer inhibition trumps a sleep aid every time. Especially when glycine works just (or almost) as well without the cancer implications.
I think we’ve flogged this dead horse enough for now…
@desertshores I enjoy discussing with you and truly appreciate your point of view. I wish you the fullest and longest life possible, my friend!
I just wanted to say that I appreciate this site and all the members who contribute. My quality of life has increased quite a bit this year after starting rapa and the other changes I’ve made from learning here. I’m just an ordinary woman in every way who is determined to make the best of the (hopefully long) time I have left here on this earth. Learning what helps others gives me ideas to consider a few of which have been extremely helpful. Knowing the potential pros and cons is valuable as well in making the best decisions possible based on our personal risk tolerance. Ultimately I’m responsible for myself and what I choose to do and take but I 100% appreciate everyone willing to share and discuss in such a mature manner. A special thank you to @DeStrider and @desertshores for the contributions in this thread (and all of your other postings through out the forum!).
Excuse any errors as I typed this up on my phone in a bit of a rush. Hopefully it’s legible. 