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Endocrine System (Diseases & Physical Ailments, Kindle eBooks): Amazon KDP category data
Amazon Kindle eBooks Best Sellers data for Endocrine System (Diseases & Physical Ailments, Kindle eBooks), updated Nov 2, 2026: median price $8.74, median 32 reviews, average rating 4.5 and a KDPTop opportunity score of 30/100 (highly competitive).
| Price range (middle 50%) | $3.99 – $9.99 |
|---|---|
| Average rating | 4.5 |
| New releases (90 days) | 16% |
| Books on the list | 100 |
| Store | Kindle eBooks |
What stands out
- Its median reviews are 4% of the parent category Diseases & Physical Ailments (714), one of the easier corners under it.
- 16% of its best sellers came out in the last 90 days, more than in 78% of Kindle eBooks categories: readers here keep buying new titles.
- Prices spread wide: the middle half runs from $3.99 to $9.99, so budget editions and premium or boxed sets sell side by side.
Top 10 Endocrine System best sellers
-
Cortisol Aging: 8 Signs Your Body Is Aging Faster: The 30-Day Protocol to Lower Stress, Lose Stubborn Belly Fat & Feel Like Yourself Again (The S.W.A.W. Reset Series)
by Max Tassy
- List rank#1
- Price$2.99
- Rating5.0
- Reviews17
-
The Modern PCOS Diet Cookbook for Beginners: Take Full Control of Your Hormonal Balance for Weight Loss and Fertility (with 12-Week Meal Plan & Shopping Lists)
by Cassandra McKinney
- List rank#2
- Price$2.99
- Rating4.5
- Reviews104
-
Cortisol Fix: Why you're exhausted, wired, and can't lose weight-and exactly what to do about it (Gut and Hormone Health Series)
by Heidi Moretti
- List rank#3
- Price$5.99
- Rating4.5
- Reviews45
-
Medical Medium Thyroid Healing: The Truth behind Hashimoto's, Graves', Insomnia, Hypothyroidism, Thyroid Nodules& Epstein-Barr (Medical Medium Series Book 3)
- List rank#4
- Price$10.99
- Rating4.6
- Reviews11,021
-
The Menopause Moment: Mindset, Hormones and Science for Optimal Longevity
by Kelly Casperson M.D.
- List rank#5
- Price$12.99
- Rating4.8
- Reviews321
-
The Power of Your Thyroid and Adrenals: How They Shape Your Health Throughout Life and How to Heal Them
by Elizabeth Bright
- List rank#6
- Price$15.99
- Rating4.6
- Reviews143
-
Hashimoto’s Food Pharmacology: Nutrition Protocols and Healing Recipes to Take Charge of Your Thyroid Health
- List rank#7
- Price$21.99
- Rating4.6
- Reviews1,357
-
Hashimoto's Protocol: A Groundbreaking Prescription to Reverse Symptoms, Heal Autoimmune Damage, and Reclaim Your Life with Personalized Detox Plans, Nourishing Recipes, and Proven Treatment
- List rank#8
- Price$20.99
- Rating4.6
- Reviews4,494
-
Prediabetes After 60 for Beginners: The Easy 30-Day Plan to Reverse and Manage Blood Sugar Naturally with Simple Meals and Senior-Friendly Routines
by Franklin Hayes
- List rank#9
- Price$8.99
- Rating4.7
- Reviews9
-
The Thyroid Connection: Why You Feel Tired, Brain-Fogged, and Overweight -- and How to Get Your Life Back
by Amy Myers MD
- List rank#10
- Price$1.99
- Rating4.5
- Reviews1,321
Same niche in Books: Endocrine System
FAQ
Is Endocrine System a good niche for Amazon KDP?
Its KDPTop opportunity score is 30/100, which makes it highly competitive. The median best seller has 32 reviews and sells for $8.74.
How many reviews do you need to rank in Endocrine System?
The median best seller has 32 reviews, and 63% of them have fewer than 100.
What do Endocrine System best sellers cost?
The median price is $8.74; half of the best sellers are priced between $3.99 and $9.99.
Can new books break into Endocrine System?
16% of the current best sellers were released in the last 90 days.
About this data
Data comes from KDPTop's daily crawl of Amazon's public Best Sellers pages; medians use the latest list. The opportunity score (0–100, higher is easier to enter) combines the review barrier, the share of low-review books, list turnover, new-release share and price.