EDIT: scroll down towards the bottom towards the bottom for my answer. Its thoracic outlet syndrome. If I do certain stretches it goes away. Its an issue related to my bad posture and nerves getting pinched (from sitting in front of a computer the whole day)


I have mild Raynauds, which means the tips of my fingers are usually the same temperature as the atmosphere of the room/outside. (unrelated: I don't have any autoimmune disease, but I think this is from typing my whole life)

Anyways, I started to notice that when I chew this gum called "NeuroGum" found on Amazon, my fingers warm up. I'm very curious, what ingredient(s) could be causing my hands (finger tips) to warm up. Here is the list of core ingredients, (copy+pasted from amazon)

Ingredients Sorbitol, gum base, L-theanine, Natural Flavors (Vanilla and Mint), Natural caffeine, Calcium Stearate, Steviol Glycosides, Acesulfame K, Vitamin B6 (as Pyridoxine), Vitamin B12 (as Cyanocobalamin) note:its "Vitamin B12 (as Methylcobalamin)" on my gum

The only other thing that has similar effects is alcohol. I've tried buying the (same form of) b12 and b6 and l-theanin supplements and trying those separately/individually. This has not shown any success, (although I'll keep trying)

EDIT: one more ingredient that i've noticed ALWAYS makes my hands warm is melatonin, (sleeping aid). Specifically this brand of mouth dis-solvable ones. "NATROL® MELATONIN ADVANCED SLEEP MAXIMUM STRENGTH 10 MG." I've also tried chewing caffeinated gum without any success

  • This will take some time to answer. You could speed up this process by partially self-answering your question, which is similar to this one. The only trouble is that there are multiple ways to get someone warm and it isn't as easy to answer as the linked post
    – Narusan
    Commented Jul 11, 2018 at 12:23
  • You will very likely know if caffeine (coffee, tea, cola..) has any effect...?
    – Jan
    Commented Jul 12, 2018 at 11:33
  • Caffeine has no affect, I tried drinking cold coffee as a baseline. No luck
    – Hercslure
    Commented Jul 18, 2018 at 3:03
  • 1
    Thoracic outlet syndrome is a diagnosis a doctor made? Have you ever got a diagnosis of Raynaud's?
    – Jan
    Commented Oct 6, 2018 at 8:39

3 Answers 3


The ingredients one by one

  • Sorbitol:
    An alcohol sugar, and a sugar substitute. However, xylitol has become more widely used because a few type of bacteria (Streptococcus mutans) can process sorbitol and as such it is more anticariogenic.

    In addition, sorbitol has one-third fewer calories and 60 % the sweetening activity of sucrose and is used as a sugar replacement in diabetes.
    Source: PubChem

  • L-theanine:
    The use of theanine is widely debated:

    The German Federal Institute for Risk Assessment, an agency of their Federal Ministry of Food and Agriculture, objects to the addition of L-theanine to beverages. The European Food Safety Authority EFSA advised negatively on health claims related to L-theanine and cognitive function, alleviation of psychological stress, maintenance of normal sleep, and reduction of menstrual discomfort. Therefore, health claims for L-theanine are prohibited in the European Union.
    Source: Pubchem

    Its mechanism of action is pretty complicated, it appears to be mostly are neuro-agent (although literature is contradictive there as well), but I'll research more.

  • Caffeine:
    Caffeine is a vasoconstrictor. As such, it constricts the arteries and - in this case more importantly - the arterioles. The skin turns paler because less blood reaches it surface. This way, heat radiation from the skin is limited in the extremities. This also happens when you feel cold, and it explains why feet and hands start to get cold first. This is however the opposite of what you describe (but similar to the way Raynauds affects your body temperature)

  • Calcium Stearate:
    Nothing more than a flow agent and surface conditioner, also used in other candies such as Smarties

  • Steviol Glycoside:
    Artificial sweetener, more commonly known as Stevia.

  • Acesulfame K (potassium):
    Another artificial sweetener

  • Vitamins and Flavour Agents
    They won't have anything to do with it.


  1. It is the caffeine. This is kind of contradicting what I wrote above, but some studies associate the caffeine with hot flashes in the female menopause. The underlying mechanism is not yet understood (and in fact, other studies claim that caffeine decreases the risk), but that might be.

  2. It's a placebo effect. Maybe you once felt warmer due to other reasons after consuming it, and now it's just a placebo.

  • I really appreciate you taking the time to look into this. 1. I've tried drinking cold coffee and it doesn't seem to make a difference either way. 2. I've thought about that. There's no way its the placebo, there is a color change in my fingers. I sit at my desk all day and type (software developer), I don't have variation in my schedule. It can't be the placebo. Chewing normal gum, for example, has no effect. I drink ice water to lower my core temperature during experiments
    – Hercslure
    Commented Jul 18, 2018 at 3:05
  • The way the last bullet is phrased I have to disagree. Niacin flush was pretty popular to get in the nineties with "herbals" / and in this case B6 can be dosed in "who knows how high" (although that is thenprobably longterm damage…). || Just having just "read" the "science" tab on the manufacturer site I would strongly opt for I want to please effect. Commented Oct 6, 2018 at 17:20

Your experience that alcohol warms your fingers and the fact that the drug nifedipine is used in Raynaud's symptoms relief suggest that the mechanism involved in warming fingers is vasodilation.

From the list of ingredients in your product, L-theanine can cause arterial vasodilation and could therefore be theoretically responsible for symptoms relief.

Caffeine can have a vasoconstricting effect, but, according to UpToDate, "its xanthine-related properties may result in systemic vasodilation," which may result in fingers warming.

I have not found any credible medical source that would suggest either L-theanine or caffeine for treatment of Raynaud's, though.

Melatonin can also have a vasodilating effect (PubMed):

When ingested as a supplement in humans, melatonin enhances the cutaneous vasodilating response during heating and blunts the cutaneous vasoconstrictor response during cooling.

  • I really appreciate you taking the time to look into this. 1. I've tried drinking cold coffee and it doesn't seem to make a difference either way. Are there different kinds of caffeine? This one is extracted from tea and "cold" fused... or something like that
    – Hercslure
    Commented Jul 18, 2018 at 3:11
  • 1
    Caffeine is always the same and it is also the same as "theine" in tea. But there are other ingredients that are or are not present in various types of coffee, and I don't know what their effects on blood vessels are. Anyway, most related websites advise against consuming caffeine, because it may have more vasoconstricting than vasodilating effect.
    – Jan
    Commented Jul 18, 2018 at 9:39
  • Thank you. Its a very bizarre condition, there are several variables and possibilities. It could be anything, I've read all sorts of things, and I thought I'd reach out here and try my luck. I reached out to the CEO of that gum company and he didn't know answer. At this point, I'm considering getting surgery. Again I really appreciate the help
    – Hercslure
    Commented Jul 20, 2018 at 4:49
  • Have you seen any difference at times when you have a longer break from typing? Would you think anxiety is a trigger?
    – Jan
    Commented Jul 20, 2018 at 8:39
  • I think anxiety is definitely a trigger... but then again I've been in stressful situations (in cold places) where I've seen the exact opposite effect. I really have no idea what's going on. I have also never been away from the computer for long enough to see any noticeable difference
    – Hercslure
    Commented Jul 22, 2018 at 0:16

EDIT: Its thoracic outlet syndrome. If I do certain stretches it goes away


So I looked into it, and I found those ingredients are actually good for "carpel tunnel" which has been found to be related to raynauds in some cases... this is essentially a pinched nerve due to bad posture (common in computer scientists). I don't think I have this in my hands, but probably in my shoulders or back (from hunching over a computer all day over years). So I started looking into youtube videos relating to this and got some suggestions for things to try. Luckily I have found that when I straighten my neck back (and decompress the right bone/nerve), I can feel the problem going away immediately. Its weird, I can't really explain it but I also notice an almost immediate difference in the way my hands feel.

Anyways, I'm going to a good chiropractor to investigate and hopefully correct this problem, I will update this thread later with any updates. We will see.

Also important to note I've never had it in my toes or anything.

  • 1
    Carpal tunnel syndrome includes pain in the wrist (not necessary) and tingling or numbness in the thumb, index and middle finger and related part of the palm. Wrist use is a trigger and wrist rest is a reliever. A pinched nerve in the cervical spine (due to a herniated disc or arthritis) can cause pain in the neck and shoulder (not necessary) and tingling/numbness on the thumb side of the hand. In general: nerves = pain/tingling/numbness; arteries = cold sensation, color changes.
    – Jan
    Commented Sep 21, 2018 at 8:42

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