Comparison Overview
Both are top contenders in the speed training category. Try both to find your preference.
How the Saucony Endorphin Speed 5 and Adidas Adizero Boston 12 differ
The Saucony Endorphin Speed 5 and the Adidas Adizero Boston 12 sit in the same speed training bucket, so the question isn't what you'd use them for — it's which one matches your stride, your weekly mileage, and your budget.
Where they actually differ: the Saucony Endorphin Speed 5 comes in roughly 0.2 oz lighter (8.3 oz vs 8.5 oz), which becomes noticeable on faster turnover and longer efforts; the Adidas Adizero Boston 12 rides on the taller stack (32mm/24mm vs 38mm/30mm), giving it more under-foot cushioning at the cost of a slightly less stable platform; and the Adidas Adizero Boston 12 is $15 cheaper at MSRP ($175 vs $160).
Head-to-Head Comparison
| Feature | Saucony Endorphin Speed 5 | Adidas Adizero Boston 12 |
|---|---|---|
| Brand | Saucony | Adidas |
| Model | Endorphin Speed 5 | Adizero Boston 12 |
| Category | speed training | speed training |
| Weight | 8.3 oz | 8.5 oz |
| Drop | 8mm | 8mm |
| Price | $175 | $160 |
Frequently Asked Questions
- Which is lighter, the Saucony Endorphin Speed 5 or the Adidas Adizero Boston 12?
- The Saucony Endorphin Speed 5 is the lighter shoe at 8.3 oz versus 8.5 oz.
- Which costs less?
- The Adidas Adizero Boston 12 is the more affordable option at $160 compared to $175.
- Can I rotate both shoes in the same training block?
- Yes — many runners pair complementary shoes like these to spread load across different muscles and tendons. Use our rotation planner to build a mileage split that fits your schedule.
Read the full reviews
- Saucony Endorphin Speed 5 — full specs, AI insights, and verdict.
- Adidas Adizero Boston 12 — full specs, AI insights, and verdict.
- Browse the full running shoe database
- See more shoe comparisons
Not sure which is right for you?
Use our AI-powered shoe finder for personalized recommendations, or build a smart shoe rotation with the rotation planner.