The Soylent Side Effect Experiments Thread


As requested by @soylentnoight in the Let’s be honest: Soylent 1.0 has problems for many people thread, I am creating this thread to compile my own experiments and reports in one place, and invite others to share their findings here as well.

So, there are a number of side effects that have been reported by customers of Soylent 1.0 so far. Most notably:

  • Gas
  • Headaches
  • Aftertaste
  • Fatigue

Gas is by far the most common, but headaches have been reported by quite a few people as well, including myself. Personally, the gas and bloating was enough for me to sell off the remainder of my month’s supply of Soylent, since I do much better on my own DIY.

For me the aftertaste is comparable to that of eating any sugary or starchy food, triggering the growth of yeast on my tongue which leaves a whitish coating and a sour taste. Apparently yeast love maltodextrin, the primary ingredient in Soylent.

Because I’ve experienced no side effects with most of (but not all) my DIY, I decided to individually test each ingredient used in Soylent which I do not use in my own stuff, to see if I can pinpoint a single culprit.

These four ingredients are…

  • Gum Arabic (aka Acacia Gum), 4.5g in 2000 calories of Soylent
  • Vanillin, 1.8g in 2000 calories of Soylent
  • Sucralose, 0.06g in 2000 calories of Soylent
  • Soy Lecithin, 6g in 2000 calories of Soylent

Measurements come from this official blog post on Soylent additives.

I will follow up with a log of my own experiences.

The Paleo(ish) soylent - axcho reviews Ample
Soylent 1.0 Experience - OmegaJeff
Cricket Soylent – high carb athletic mid-30s female ($$$)

I have already done a couple week’s worth of trials so far. Here are the results I’ve experienced:

June 27th:

July 3rd:

July 4th:

July 7th:

July 8th:

July 10th:

July 11th:

July 12th:

July 14th:

July 16th:

July 17th:

I am still experiencing gas and bloating today.

It seems that evidence points strongly toward Gum Arabic as the culprit for gas, and Vanillin as the culprit for headaches (at least in my case).

I look forward to hearing the reports of any others who are conducting similar trials.


Pioneer you are…


Just to make your effort more noticed and hopefully have this things considered for 1.1 @rob… did you test yourself or can you try approve these findings?


I’m thinking that the gum arabic may be causing the volume of gas, but it could be the high-sulfur rice protein that gives it the smell.


Yes, I completely agree. When consuming gum arabic but not rice protein, the gas is copious but not deadly. :stuck_out_tongue:


Thanks for volunteering yourself as a guinea pig… Interesting results so far!


Great post. And here’s some interesting information about gum arabic:

Sure enough, it can cause gas and bloating. It can also interfere with absorption of the antibiotic amoxycillin… just FYI for anyone who happens to be taking that!


Fascinating, thanks for the info!


Where can I get more details on the different formulas you offer, I would like to see if I can get rid of the headache, and digestive issues and would be willing to try something else. I’m not a fan of animal based products though so that’s a factor.


Hi @NoFlames, all my recipes are available here on the DIY Soylent site, with full details. Some are vegan (and tagged accordingly), and almost all have links to where you can order them from me on my site.


The posts that I would ask all Soylenteers to consider liking are:

  • [Dear Rosa Labs: Let’s talk about updates][1] by @dialogos
  • [A great ‘Example Update’ (in response to “Soylent Update 7/18”)][2] by @Karunamon
  • [The Soylent Side Effect Experiments Thread][3] by @axcho

For those Soylenteers that are unaware, the discourse forum that we are currently using supports badges.  Among the badges is one for “Great Post”.  To qualify as a great post, a post must receive 50 or more likes.  [The Great Post badge is the only real badge that has yet to be granted!][4] (One of two if you count “Elder”; which has only be granted to the system.)  I’ve seen three posts recently that I believe are deserving of a “Great Post” badge.  So, I’m encouraging everyone to read these posts and - if you concur that they are valuable messages for Rosa Labs - click the grey :yellow_heart:  icon below the post (you can confirm that you’ve liked a post by finding the statement, “You and x other people liked this.” near the heart icon and reply button.)  It would rock if the Rosa Labs team came in Monday morning to three great posts, one that explains why the most recent update was so unfulfilling and two examples of what would be fulfilling information!

Cross-posting to each of the posts to bump their threads.



I was feeling tired after drinking Soylent and @axcho sent me some vanillin (and sucralose) to test whether I was having a reaction to it. About 15 minutes ago, I drank about a gram of vanillin mixed in water. Soylent has 1.8 grams per packet. So that’s a little over a serving and a half’s worth. And, I definitely feel fatigued. I think there’s a good chance the vanillin in Soylent is what is making me feel tired after drinking it. It’s at least a factor.

How the heck do you use vanillin?

Interesting… that’s twice now that vanillin has been implicated in odd side effects.


I’m wondering if the vanillin thing isn’t due to its alcohol base. Different brands of vanillin use alcohols of differing type and quality. It’s not usually an issue because the vast majority of the time, it’s being used in a small dose combined with a lot of absorbent ingredients, and more often than not, it’s baked (or otherwise heat-treated), and alcohols evaporate very easily. I’m not sure exactly how that works out in a soylent context, but as regards direct sampling, I’d assume that’s a bigger factor than the vanillin itself.


I also wonder if, since vanillin is the most noticeable flavor note in Soylent, if people try vanillin after they’ve had some kind of reaction to Soylent, they could be getting a conditioned response. We need people to try vanillin before they’ve experienced Soylent.


Vanillin in powdered form mixed with water tastes like a harsh chemical concoction. Not at all like the taste of Soylent. So I doubt it.


Hmmm. Okay.


tldr: Badges? we don’t need no stinking badges.

Gamification is ruining the internet. I was very disappointed when discourse jumped on the bandwagon. If someobe is so insecure you need other people “likes” to produce quality posts, or tell them what to read, they should probable seek professional help, rather than spend all day trying to get badges.

rant over.


Starting my 8th day of 75-100% of my meals on Soylent. I’ve had no headaches and no abnormal gas. The gas I have had, isn’t worthy of calling a weapon of mass destruction like mustard gas. :frowning: I was kinda disappointed there. I have noticed I haven’t had a single “eat and hit the bathroom” caused by mild IBS/lactose intolerance. I even ate morning/lunch Soylent and got talked into going to eat a Patty melt at a bar for lunch and no adverse effects outside of feeling very full. :stuck_out_tongue: