r/MCAS↗
A science-focused sub for Mast Cell Activation Disorders. Please note: The content on this subreddit is not intended as, and is not a substitute for, medical advice or diagnosis. It must not be interpreted as such. You are strongly advised to consult your own qualified healthcare professionals for any medical questions or concerns.
60k subscribers1,181 posts / mo in Sep 2026849 authors / mosince 2013
r/MCAS has 60k members (+59% over the last 12 months). It gets about 1,181 posts a month from 849 people. Top topics: Picky Eaters, Scalp Issues and Fragrance Discussions.
When to post on r/MCAS
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How r/MCAS has grown
Subscriber growth
Subscribers over time
Monthly activity
Posts, comments and authors per month
Topics and brands on r/MCAS
Top topics
Share of the subreddit's posts
- Picky Eaters<0.1%
- Scalp Issues<0.1%
- Fragrance Discussions<0.1%
- Sushi Making & Ingredients<0.1%
- Cat Allergies & Hypoallergenic Breeds<0.1%
Brands people mention
Most-mentioned brands and sites, last 12 months
- Mastzellaktivierung
- Mast Cell 360
- ScienceDirect
- Substack
- Drugs
Everything else about r/MCAS
Posting rules and account requirements, how often posts get removed, who writes here (age, gender, countries), what people ask for, how they talk, and related subreddits — all in the full report.
Posts and activity for Sep 2026. Members from Reddit's subscriber counts. Read from the same data the app runs on. Our research